TITLE PRODUCTION AND CHARACTERIZATION OF PLASTIC FROM MARINE ALGAE
RAMANAN A/L NADARAJAN
Thesis submitted in fulfillment of partial requirements for the award of degree of Bachelor of Chemical Engineering
Faculty of Chemical and Natural Resources Engineering UNIVERSITI MALAYSIA PAHANG
JANUARY 2013
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SUPERVISOR’S DECLARATION
“I hereby declare that I have read this thesis and in my opinion this thesis has
fulfilled the qualities and requirements for the award of Degree of Bachelor of Chemical Engineering”
Signature
: __________ _____________________ ______________________ ____________ _
Name of Supervisor Supervisor
: DR. MOHAMMAD DALOUR DALOUR HOSSEN BEG
Position
: SENIOR LECTURER
Date
: 24 JANUARY 2013
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STUDENT’S DECLARATION
I declare that this thesis entitled “Production
and Characterization of plastic from
Marine Algae” is the result of my own research except as cited in references. The thesis has not been accepted for any degree and is not concurrently submitted in candidature of any other degree.”
Signature
: ___________ _______________________ __________________ ______
Name
: RAMANAN A/L NADARAJAN NADARAJAN
ID Number
: KA09072
Date
: 24 JANUARY 2013
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To my beloved family and friends
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ACKNOWLEDGEMENTS
I would like to express my humble gratitude to my supervisor, Dr. Mohammad Dalour Hossen Beg who have supervised and supported me throughout the entire process of this research with his patience and knowledge whilst allowing me to work on my own pace. Endless guidance was given by him to push myself to become a better researcher and also as a future engineer. One could not have had a friendlier supervisor. Next, I also would like to express my gratitude towards Mr. Reman for his guidance, suggestions, co-operations and supports in running the research. Special thanks to Faculty of Chemical & Natural Resources Engineering, University Malaysia Pahang (UMP), especially the lecturers, administrative staffs and laboratory assistants, for the help and advises, and to those who involves directly or indirectly in the completion of my project. Lastly, I would like to thank all my family and friends who deserve a token of appreciation for the support that enabled me to successfully finish this thesis.
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TABLE OF CONTENT Title
Page
No. Cover Page
i
Supervisors Declaration
ii
Students Declaration
iii
Acknowledgement
v
Table of Content
vi
List of Figures
viii
List of Tables
xi
List of abbreviations
xii
Abstract
xiii
Abstrak
xiv
1.0 Introduction
1
1.1 Background of Study
1
1.2 Problem Statement
6
1.3 Research Objective
6
1.4 Scope of Study
7
1.5 Significance of Study
7
1.6 Conclusion
8
2.0 Literature Review
9
2.1 Introduction
9
2.2 Marine Algae
10
2.3 Low Density Polyethylene
15
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2.4 Structural Modification
18
2.5 Polymer Blending
21
2.6 Polymer Characteristics
22
2.7 Conclusion
25
3.0 Methodology
27
3.1 Introduction
27
3.2 Processing Flow Chart
28
3.3 Materials
29
3.4 Equipments
29
3.5 Method of Research
33
4.0 Results and Discussions
35
4.1 Introduction
35
4.2 Extrusion Process
37
4.3 Hot Press: Parameter Optimization
38
4.4 Differential Screening Calorimeter (DSC) and Thermo gravimetric Analyser (TGA
41
4.5 Tensile Testing
45
4.6 Water Absorption Test
48
4.7 Conclusion
49
5.0 Conclusion and Recommendations
51
5.1 Conclusions
51
5.2 Recommendations
51
Reference
53
Appendix
54
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LIST OF FIGURES
FIGURE NO.
1.1
TITLE
Chemical structure of the repeating dimeric
PAGE
3
units of λ -carrageenan
1.2
Chemical structure of the repeating dimeric
4
units of fucoidal 2.1
Molecular structures of marine algae extract
11
2.2
Enzymatic modifications of amylase and
19
amylopectine with amylomaltase 2.3
FTIR analyses Peaks
23
2.4
DSC analysis peaks
24
2.5
TGA Analysis diagram
25
4.1
Plastic Blend 5%, 10%, 15%, and 20% for top left to bottom right
36
4.2
Graph of Tensile strength vs. Temperature
39
4.3
Graph of Tensile Strength vs. Time
39
4.4
Mould (top), Dog bone testing sample (bottom)
40
4.5
: DSC Profile for 5% of algae
41
4.6
Graph of Melting Point vs. Algae Composition
42
4.7
Graph of Glass Transition Temperature vs. Algae Composition
43
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4.8
TGA profile for 5% algae composition
44
4.9
TGA profile for 20% algae composition
45
4.10
Graph of Tensile Strength vs. algae composition
47
4.11
Graph of Elongation vs. Algae Composition
48
4.12
Graph of Water Absorbance vs. Composition
48
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LIST OF TABLES
TABLE NO.
TITLE
PAGE
2.1
Proteins in algae
14
3.1
blending composition of samples in % and grams
34
4.1
Hot Press Temperature optimization
38
4.2
Hot Press Time Optimization
39
4.3
Glass Transition Temperature and
42
Melting Temperature from DSC test 4.4
Tensile Strength and Elongation at Break profile
46
for varying algae composition 4.5
Water absorption profile with varying algae composition
x
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LIST OF ABBREVIATIONS
DSC
Differential Screening Calorimeter
EVA
Ethylene Vinyl Acetate
FE
Formaldehyde Emission
FTIR
Fourier Transform Infrared spectroscopic
HDPE
High Density Poly Ethylene
LDPE
Low Density Poly Ethylene
NP
Natural Pigment
OSB
Oriented Strand Board
PP
Polypropylene
RTV
Room Temperature Vulcanizing
SEM
Scanning Electron Microscopic
TGA
Thermo-gravimetric Analyser
UV/V
Ultra-violet Visible Spectrophotometer
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LIST OF SYMBOLS
C
Degree Celsius
%
Percentage
MPa
Mega Pascal
USD
United States Dollar
RM
Ringgit Malaysia
Tons
Tonnes
$
Dollar
pH
Power of Hydrogen
˚F
Degree Fahrenheit
g/cm3
Gram per centimeter cube
µm
Micro meter
mm
Millimeter
M
Molarity
V
Volume
mL
Milli-Liter
g
Gram
h
Hour
cP
Centipoises
wt.
Weight
s
Second
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PRODUCTION AND CHARACTERIZATION OF PLASTIC FROM MARINE ALGAE
ABSTRACT
The two main objective of this research is to test the viability of using marine algae as a profound bio-filler for the production of plastic where the plastic produce will have the tendency to reduce usage of non-renewable recourse which contributes to severe ecological problems. The second objective is to characterize the plastic blend produced using marine algae via physical, mechanical and thermal testing. In this study, Marine algae and Low density polyethylene is used as raw material and blended to produce plastic sample which later on was characterized using Differential Scanning Calorimeter (DSC), Thermogravimetry Analyzer (TGA), and tensile tester as well as water absorption tests. The results concluded that these red marine algae are not suitable for plastic production without any modification. This is due to the fact that it have weak mechanical properties and also very high water absorbance level which contributes mechanical failure under moist conditions.
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PENGHASILAN DAN PENCIRIAN PLASTIK DARIPADA PLASTIC ALGA MARIN
ABSTRAK
Dua objektif utama kajian ini adalah untuk menguji kebolehan menggunakan alga marin sebagai bio-pengisi yang berkemampuan tinggi untuk penghasilan plastik di mana plastic and dihasilkan akan mempunyai kecenderungan untuk mengurangkan penggunaan sumber tidak boleh diperbaharui seperti petroleum yang menyumbang kepada masalah ekologi yg membimbangkan. Satu lagi objektif adalah untuk mencirikan campuran plastik dihasilkan menggunakan alga marin melalui ujian fizikal, mekanikal dan degredasi haba. Dalam kajian ini, alga Marin dan polietilena berketumpatan rendah digunakan sebagai bahan mentah dan dicampur untuk menghasilkan sampel plastik yang kemudian dicirikan menggunakan kalorimetri pengimbas pembezaan (DSC), Analyzer termogravimetri (TGA), dan penguji tegangan serta ujian penyerapan air. Keputusan menyimpulkan bahawa alga marin merah tidak sesuai untuk pengeluaran plastik tanpa sebarang pengubahsuaian struktur molekulnya. Ini adalah disebabkan oleh ia mempunyai sifat-sifat mekanikal yang lemah dan juga tahap penyerapan air yang sangat tinggi yang menyumbang kepada kegagalan mekanikal di bawah situasi yang berkelembapan tinggi.
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CHAPTER 1
Introduction
1.1 Background of study
A brief history of plastics predates back to middle ages. During these times, plastics were mostly naturally occurring polymeric compounds which were used to derive product of daily use. One of the examples would be the usage of animal horns in building window frames and lantern heads. As time progressed, substitute polymeric materials were made from lye treated milk protein-solids (casein). It was a breakthrough when Charles Goodyear's discovery of vulcanization as a route to create sulphur chains in materials derived from natural rubber was commercialized. Thus from then till today the polymeric industry have underwent continuous revolution in search of alternative and more suitable materials for various purposes. In this research, the compounding of plastic blends with structurally modified marine algae culture is to be studied as a new and profound way to progress towards an environmental friendly production of plastics. Thus, we will discuss the
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two major elements which is the core of this research, first being the study of the algae and next the blending of plastics itself.
1.1.1
Marine Algae
Marine algae, more commonly known as seaweeds, come in various shapes and sizes. Algae are not plants, even though they sometimes look like them. Algae are relatively undifferentiated organisms which, unlike plants, have no true roots, leaves, flowers or seeds. Algae do not have water-conducting tissues, as they are, at some stage, surrounded by water, which is also important for reproduction by spores. The spores may be motile or non-motile. Most of the algae are photosynthetic organisms that have chlorophyll. Apart from chlorophyll, they contain additional pigments, which are the basis of classification. Most of the seaweeds are red (6000 species) and the rest known are brown (2000 species) or green (1200 species). Seaweeds are used in many maritime countries as a source of food, for industrial applications and as a fertilizer. Nori, a type of Japanese red seaweed has a high protein content (25-35% of dry weight), vitamins (e.g. vitamin C) and mineral salts, especially iodine. Industrial utilization is at present largely confined to extraction for phycocolloid, industrial gums classified as agars, carrageenan and alginates. Agars, extracted from red seaweeds such as
Gracilaria , are used in the
food industry and in laboratory media culture. Carrageenan, extracted from red seaweeds are used to provide particular gel qualities. Alginates are derivatives of alginic acid extracted from large brown algae, are commonly used as They are used 2
in printers' inks, paints, cosmetics, insecticides, and pharmaceutical preparations. Alginates are used as stabilizers in ice cream. In recent studies, there are an increasing number of researchers done which are looking to get plastics from the sea by using marine life forms as a raw material to make polymers. Algae are the most promising area of research right now. It is already widely used as a raw material for biofuels, but this is increasingly extending to plastics. The theory behind biopolymers is that they use sustainable resources, rather than petrochemicals. The usage of naturally occurring sulphated polysaccharide and phenolic polysaccharide which can be derived from these marine algae is largely used as blending material for bio plastics. According to Frederic Scheer, CEO, Cereplast one of the bio-plastic producing company, resin is to be extracted from this crop to produce bio-adhesives which can be used to make polymeric compounds. It is similar of how starch from corns and other commercialized crops were used in obtaining polymers which will acts various additives and matrix components in plastic production.
Figure 1.1: Chemical structure of the repeating dimeric units of λ -carrageenan
3
Figure 1.2:
1.1.2
Chemical structure of the repeating dimeric units of fucoidal
Plastic and Plastic Blending
Plastic materials are range of products which are blended from synthetic or semi synthetic organic solids that are moldable. Plastics have high average molecular weight compared to other types of polymers and also contain other substance. These plastics are most commonly synthesized from petrochemicals and are often are derived with various characteristics and functions. The vast majority of these polymers are based on chains of carbon atoms alone or with oxygen, sulphur, or nitrogen. Plastics consists of carbon repeating unit which is linked together to form a polymeric chain which is also known as the back bone. To customize the properties of a plastic, different molecular groups attached to the backbone, as the side chains influences the properties of the side chains. Compounding consists of preparing plastic formulations by mixing and blending polymers and additives in a molten state. There are different critical criteria to achieve a homogenous blend of the different raw material. There are multiple additives that is being used in plastic blending and formulation.
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Fillers are mainly particles which are added to plastic compounding in order to lower the consumption of more expensive binder material or to better some properties of the mixture material. Formerly, fillers were used predominantly to cheapen end products, in which case they are called extenders. Coupling agents or better a polymeric coupling agent is a polymer that attaches inorganic filler to the polymer matrix. Coupling agents have to be added in order to reduce the repellence of the polymers and fillers respectively. This is because fillers are largely added to polymer matrix in order to reduce the cost and so on. Plasticizers or dispersants are additives that increase the plasticity or fluidity of a material. The most commonly used plasticizer is phthalate ester. It is used to upgrade or improve the flexibility and durability of plastic materials. Flame retardant is chemicals used in thermoplastics, thermosets, textiles and coatings that inhibit or resist the spread of fire. There additives are often added to make the product more resistive towards thermal decomposition with different mechanisms. Colorant is another additive which is used to give the produced plastic material a suited colour. There are 2 methods of colour addition, first is the pigment addition. This mainly involves addition of metallic colour pigment to provide the colour and the next method is to use azonium dye.
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1.2 Problem Statement
As there is an increasing awareness on environmental issues, the producing of traditional petro-chemically derived plastics is not favorable. This is due to the fact that synthetic plastics have high resistance towards environmental degradation which takes up to thousands of years to decompose. The only way to dispose is through land fill. Due to this, bio plastics are becoming a new replacement for synthetic compounds as it is more prone to environmental attack and decomposition. Not only that, certain qualities can also be reinforcing i.e. mechanical strengths via using natural additives or adhesives. In this study, the usage of marine algae as a filler in polymer blending is tested to produce notable bio-plastic with elevated properties and water resistance.
1.3 Objectives
There are two main objectives in this research of producing plastic from marine algae. The first objective to investigate if marine algae are a viable source of bio filler to produce plastic that is environmentally friendly whereby the plastic produced will be biodegradable and slightly decomposed to smaller substances by living organisms from marine algae.
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The second objective is to characterize the algae plastic produced via TGA (thermal gravimetric analysis), DSC (differential scanning calorimeter), FTIR (Fourier Transformed Infrared Spectrometer), and water absorption testing.
1.4 Scope of study
The scope of this research includes the description and characterization of the marine algae that will help in the plastic production process. Besides that the blending of marine algae using different percentage of matrix and fillers (marine algae) is also to be studied. The blended plastic is characterized according to the objective of the research.
1.5 Significance of study
The result of this study will be a breakthrough in producing commercial grade of bio-plastic as a substitution for existing synthetic plastic. Furthermore, the enhanced properties and water resistive adaptation will be also promise a better material production proposes.
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1.6 Conclusion
As conclusion, the purpose of this study is to find out a new material which can be synthesized to obtain a notable plastic blend to cope with the environmental problem. This research will also benefit other researchers by providing information of characteristics of marine algae plastic for further findings and modifications.
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CHAPTER 2
Literature review
2. 1 Introduction
Formulating bio-based plastic blend is a relatively an unchartered scope of study as it has not been commercialized yet. Despite this, there were many researchers have been done where algae extract is used for multiple other factions. In this chapter, commercialized study which has been done with marine algae will be reviewed. Other than that, significant studies using Low Density Poly Ethylene (LDPE) as a blending matrix will also be reviewed. In this research, LDPE is chosen due to its usage in industry as a primary packaging material. It is the major source of plastic which cannot be biologically degraded. Thus making it bio-degradable will provide this research with a strong commercializing value. Also in this research, we will review the process of structural modification which will be done to the towards the algae extract. This step is under taken to modify the physical properties of the polymer blend which will be created. Generally, it is presumed that bio-plastics have
9
a much lower mechanical properties compared to synthetic plastic, thus to overcome this problem, this step is proposed.
2.2 Marine Algae
Seaweed can be classified into three bigger groups according to their pigmentation or in laymen term colour which are brown, green, and red. In this research we are using the red algae which have a vibrant colour due to the presence of phycoerythrin. In most algae, the primary pigment is chlorophyll which is present in most of the green plant. This algae also contains carotenoids, which are brown or yellow,and phycobilins which are either red or blue. This accounts for the colourful hues according to Khaled (1999). The red algae are multicellular which are characterized by a great deal of branching presence in its molecular structure and complex tissue where most of the algae belong to this group. The red algae are commonly found in warm water regions and tropical climates and can grow in great depts. compared to other species of algae. The red algae are a traditional part of oriental cuisine. The importance of marine algae as sources of functional ingredients has been well recognized due to their diverse usage in multiple fields of studies. It is mainly utilized in the pharmaceutical industry for is multi-vitamin possessing quality. According to Ratih Pangestutia, Se-Kwon Kima,b,* on their paper on Biological activities and health benefit effects from marine algae, the neutral pigment (NP) has 10
great deal of benefits. These NPs exhibit various beneficial biological activities such as antioxidant, anticancer, anti-inflammatory, anti-obesity, anti-antigenic and neuroprotective activities. This contribution focuses on biological activities of marine algae-derived NPs and emphasizing their potential applications in foods as well as pharmaceuticals areas. It was concluded that these NPs are an alternative source for synthetic ingredients that can contribute to consumer’s well-being, by
being a part of new functional foods and pharmaceuticals.
In another research done by Ali A. El Gamal on biological importance of marine algae, The microalgae phyla have been recognized to provide chemical and pharmacological novelty and diversity. Hence, microalgae are considered as the actual producers of some highly bioactive compounds found in marine resources. The principal use of seaweeds as a source of human food and as a source of gums (phycocollides). Phycocolloides like agar agar, alginic acid and carrageenan are primarily constituents of brown and red algal cell walls and are widely used in industry. Such property of algae exhibits an adhesive character due to the present of lignin which can be utilised as a polymeric additive.
Figure 2.1: A few molecular structure of
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marine algae extract
This proves significance to our research that since its considered a pharmaceutical product, it is vitally human friendly in addition to environmentally green material. Obtaining the saccharine which also acts as an adhesive for our polymer blend is justified as we can draw parallel and state that the material will undergo environmental degradation. Thus it is a valid source for bio-plastic production alternative.
Other than pharmaceutical usage, marine algae is also used to conduct chemical bio-sorption.This is a process where heavy metal ions such as cobalt and copper ions are bio-sorped onto the marine algae. According to K. Vijayaraghavan a, J. Jegan b, K. Palanivelu c, M. Velan a,* on their paper on Biosorption of copper, cobalt and nickel by marine green alga Ulva reticulata in a packed column, it is stated that marine algae offer advantages for biosorption because their macroscopic structures offer a convenient basis for the production of biosorbent particles suitable for sorption process applications. This is due to the fact that this saccharide contains sulphonic compound to their molecular chain. This compound acts as a good adsorption platform for various metal ions. It is also stated that the presence of phenol group in the chain aid the biosorption process as it aids localised attachment of outer substances conjuring metal ions. As for the result of the study, green algae exhibited very high copper, cobalt and nickel biosorption capacities in packed column compared to most of the biosorbents. This alga showed unique ability to remove all three heavy metal ions and retain its uptake capacity in three regeneration cycles. In context of this research, we can conclude that this quality can ease the structural modification as the bonding platform is already present in the algae regarding reagent which involves metallic catalysts and so on
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Algae are also widely considered an alternative source for bio-fuel generation. On a study done by Gholamhassan Najafi a, Barat Ghobadiana, Talal F. Yusaf b titled Algae as a sustainable energy source for biofuel production in Iran, they stated that Algae can be converted directly into energy, such as biodiesel, bioethanol and biomethanol and therefore can be a source of renewable energy. This is due to fact that like other commercialized crop, it is a plat with natural fibre or contains vast amount of polysaccharide which can be easily converted to the above stated products. Because of its higher yield non-edible oil production and its fast growth that does not compete for land with food production. Thus it is nothing but a naturally occurring biomass in the since that the cultivation time is bare minimum compared to commercialized crops. This is significant to our study as primary algae oil extracted can be used to create plastic blending. With this abundant amount of algae with no specific use, it can be commercialized via the waste to wealth concept where the algae itself does not cost much investment. . According to Frederic Scheer, CEO, Cereplast one of the bio-plastic producing company, resin is to be extracted from this crop to produce bio-adhesives which can be used to make polymeric compounds. It is similar of how starch from corns and other commercialized crops were used in obtaining polymers which will acts various additives and matrix components in plastic production.
The red algae are chosen as the research raw material due to the fact that it contains high amount of amino proteins primarily. This chains acts as the building block for the protein formation which is a natural polymer. Besides that algae also
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have good bond strength due to the presence of sulphite bonds in its microstructure which aids the plant to grow in turbulent deep waters. Rhodophyta (red algae) have this natural proteins and cellulose structure compared to other species according to Nirmal et et (2010). This makes it a suitable bio-filler which is to be used in plastic blending. There are many types of protein present in red algae. Researches are conducted utilizing these chains in order to achive dimensional stability of the plastic produced from red algae. The table below represents the types of amino acid concentration and nitrogen content in Eucheuma cottonii as reported by Patricia Matanjun (2007).
Table 2.1: Proteins in algae
Amino Acid
(mg g-1 dry Weight)
Aspartic Acid (Asp)
2.65 ± 0.15
Glutamic Acid (Glu)
5.15 ± 0.13
Serine (Ser)
2.27 ± 0.04
Glycine (Gly)
2.27 ± 0.32
Histidine (His)
0.25 ± 0.10
Arginine (Arg)
2.60 ± 0.14
Threonine (Thr)
2.09 ± 0.01
Alanine (Ala)
3.14 ± 0.11
Proline (Pro)
2.02 ± 0.09
Tyrosine (Tyr)
1.01 ± 0.12
Valine (Val)
2.61 ± 0.07
Methionine (Met) Isoluesine (Ile)
0.83 ± 0.17
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2.41 ± 0.04 Luesine (Lue)
3.37 ± 0.06
Phenylalanine (Phe)
19.07 ± 2.48
Lysine (Lys)
1.45 ± 0.48
Chemical Score (%) Most limiting amino acid
25.6 lysine
Total amount
52.86 ± 3.37
2.3 Low density poly-ethylene (LDPE)
The main reason LDPE is the primary choice in this research is because of its common usage in general industries and domestics. It is widely used as a packaging material such as high quality plastic wrappers and other plastic materials such as plastic disposable drinking bottles and other forms of thermoplastics. As per statistics, almost 75% of this material does not undergo biological degradation since its manufactured from synthetic polymer mainly from petroleum. Thus targeting this market gives an imperative value of marketing and a big step towards environmental preservation. Both usage of natural recourses and environmental problem can be reduced dramatically.
In a research done by Worawan Pechurai, Charoen Nakason _, Kannika Sahakaro on Thermoplastic natural rubber based on oil extended NR and LDPE Blends; LDPE was tested and used as a matrix for the blending. It was stated that blending of polymers has been widely investigated as a simple and practical means to 15
obtain new materials with novel properties. In this case NR and LDPE blends were considered as it produced interesting TPE materials. This type of blend is favourable because it which the excellent processing characteristics of LDPE which eases the production of thermoplastic elastomers with a upgraded quality compared to LDPE or PP. Another reason is due to its attribute of large melt viscosity and molecular weight of HDPE. This leads to inferior performance in mechanical properties. As a result, that Influence of PhHRJ-PE on rheological and tensile properties of a simple blend of 60/40 OENR/HDPE was first studied. It was found that at a given shear rate, the apparent shear stress and shear viscosity of the blend was higher compared to that of PP or LDPE. Also it was found that modulus and elongation at break of the blend with the PhHRJ-PE were higher in the experiment. This proves that mixing LDPE as the matrix is very much more favourable due to its processabilty and better mechanical property.
In another research on Nanoclay reinforced LDPE as a matrix for wood plastic composites by Omar Faruk, Laurent M. Matuana, LDPE was used as a preferred medium to enter nanoclay into the wood composite. LDPE was a preferred as to investigate the main goal of this study which was to examine whether or not the addition of nanoclay could also enhance the bending properties of LDPE matrix -based WPCs. Particular emphasis was placed on examining the effect of nanoclay types and as well as its addition sequence on the properties of the composites. Thus we can conclude that LDPE was used as matrix in this study to utilize its flexible characteristics and to test if it can induce a bending effect upon the produced composite. Enhancing the bending properties of WPCs using LDPE matrix could expand their acceptance in
16
load bearing structural applications. Again, mechanical properties of this matrix were another factor. As conclusion, the result indicated that the flexural properties of LDPE/wood-flour composites could be significantly improved with an appropriate combination of the coupling agent content and nanoclay type in the composites compared to study finding which was done using PVC as a matrix. The flexural strength of composites made with nanoclay reinforced LDPE matrix compared favourably with that of various species of solid wood.
On the paper A mechanical analysis on recycled PET/LDPE composites by Antonio F Ávila, Marcos V Duarte b. The large amount of disposable bottles presently produced makes imperative the search for alternative procedures for recycling or reuse of these materials, since they are not biodegradable. Thus the LDPE/ PET is chose due to its overwhelming usage in industry. The study suggests that the recycling of the plastic blends have potential for use not only in engineering applications but also in our daily life where their ultimate strength ranging from 22 to 28 MPa is a clear evidence of their capability. It was also emphasize that, the addition of LDPE particulates into a PET solution reduces the effective stiffness of the blend but LDPE phase gives a major contribution to milling operations, as it decreases the surface roughness by allowing a higher cohesive condition between PET and LDPE. Despite this feature, it was also clear that continuous recycling of the product will only yield in a lower graded plastic thus the final stage of incineration or landfill is inevitably unavoidable. Thus in this research, we will blend LDPE with the modified algae extract to produce a bio-plastic which will degrade with time.
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In a nut shell, other than the fact that LDPE is the major product used in packing material production, it is also largely used in researches for its optimal processing characteristics. It is also said to have better mechanical properties compared other various polymers when it comes to blending.
2.4 Structural Modification
Modification of structure of a particular polymer is carried out to enhance the positive attributes and eliminate the shortcomings of the native polymer. For example, in this part we will review how starches were modified structurally to confine them for different purposes in industry. Modification of structures an ever evolving industry with numerous possibilities to generate novel modified compounds which includes new functional and value added properties as a result of modification. This is connected to the main research as the algae extract which we have must be structurally modified as to analyse its mechanical properties in comparison with the one’s without. Moreover it is believed that modified compound have much preferred
properties in terms of industrial applications.
Referring to a journal on Progress in starch modification in the last decade of food biopolymer journal by Bhupinder Kaur, Fazilah Ariffin, Rajeev Bhat, Alias A. Karim, it was stated that starch modification includes three broad areas that are chemical, physical, and enzymatic modification. Chemical modification of starch involves the polymer molecules of the starch granule in its native form. Modification is generally achieved through derivatization such as etherification, esterification and 18
crosslinking, oxidation, cationization and grafting of starch. Physical modification can be safely used as a modification process in food products as it does not chemically alters or reforms the essential nutriendts in the product. Next is enzymatic modification which mainly used hydrolyzing enzymes in its modification. One of its products is syrup be it glucose syrup or high fructose corn syrup. These enzyme are generally derived from bacteria and fungi.One such example is high-amylose potato and pea starch with amylomaltase (AM) modified with the hyperthermophilic bacterium Thermus thermophilus.
Figure 2.2: enzymatic modification of amylase and
amylopectine with amylomaltase
According to A.L. Chaudhary a,*, M. Miler b, P.J. Torley a, P.A. Sopade a, P.J. Halley on their paper on Amylose content and chemical modification effects on the extrusion of thermoplastic starch from maize, the characterized how hydroxy proplylated maize starch thermo plastic ,mechanical processing is more efficient compared to unmodified maize starch thermoplastic. The design of experiments showed that starch type for both unmodified and modified maize had a statistically significant effect on parameters such as torque, die pressure and specific mechanical energy and that screw speed also significantly affected specific mechanical energy. With that it was concluded that modifying the hydroxyl-proply group possess a better process ability. The result of the experiment showed that hydroxypropyl modified
19
starch affects its gelatinisation behaviour by increasing interactions with water molecules which in turn can result in a lower viscosity. This was evident with a reduction in torque, die pressure when compared to the unmodified 80% amylose starch. This proves that such modification will actually rake in more profit as it reduces power consumption due to easier processability. In terms producing environmentally green plastic, blends done from maize starch is biodegradable as well as runs under a low power consumed operation due to the modified property.
In another research done on Thermoplastic starch modification during melt processing: Hydrolysis catalyzed by carboxylic acids by Antonio J.F. Carvalho a,*, Marcia D. Zambon b, A. Aprigio da Silva Curvelo b, Alessandro Gandini b, modification to the starch was done by forming ether links between chains in order to have a better mechanical characteristics to the polymer blend. This was achieved via processing glycerol-plasticized starch in the presence of non-volatile carboxylic acids which induces a acid catalytic hydrolysis and fabricated ether cross linking between the polysaccharide chains. As a result, the decrease of the molar mass of starch polysaccharides over a wide range of values by the use of small amounts of carboxylic acids, as additives during melt processing, results in a promising way of preparing biodegradable thermoplastic materials with controlled properties. One such property was a more resistance towards water absorption we it was proved the modified starch uptake less water compared to unmodified starch. As conclusion, the use of non-volatile and non-toxic acids as catalysts, provides the additional advantages of health safety and food compatibility in, e.g. packaging applications for these materials
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2.5 Polymer blending
The mixing of the matrix and the filler adhesive is one of the most crucial steps in the polymer production line. Ensuring proper blending is required to produce a uniform material in the sense of chemical composition. There are 2 main blending methods that is currently practised in the industry. First is reactive blending where chemically active reaction such as polymerization will occur during the blending process which would be done via extruder. The other methods are melting blending where there aren’t any chemical or structural modifications occurring in the
microscopic scale. In this process, the blend is created by producing a homogenous liquid of the plastic, fillers and other additives where complete mixing is ensured. In this research, melt blending is used where modified or unmodified marine algae is mixed with LDPE and extruded out.
According to Rachele Pucciariello*, Vincenzo Villani, Carlo Bonini, Maurizio D’Auria, Teresa Vetere of the journal Physical properties of straw lignin-based
polymer blends stated that melt blending is essentially a conventional polymer production method. In their study Lignin powder was used in preparation of blends with low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE) and atactic polystyrene (PS) to produce biothermoplastic. The composition of lignin and the matrix was varied. The blending was done via an extruder where both the ingredients in respective studied ratio were fed into the feed hopper, the blending commenced where both compounds were melted and blended together. The result of the study states that the modulus slightly
21
increases for most lignin-polymer blends, while the tensile stress and elongation reduce. Moreover, lignin acts as a stabilizer against the UV radiation for PS, LDPE and LLDPE.
Polymerization blending for compatible poly (ether sulfone)/ aramid blends based on polycondensation was done by Hideo Hayashi where Poly(oxy-1,4 phenylenesulfonyl-1,Cphenylene) and (PES) and poly (m-phenyleneisophthalamide) were blended readily via reactive blending. The polymerization process takes place during the blending process. The findings proved that the tensile modulus and tensile strength of the blend films were improved over the entire PESj/PMIA composition range by using the polymerization blending method. The polymerization-blended films had a high elongation at break over a relatively wide composition range compared to conventional solution blending method.
2.6 Polymer Characterization
FTIR spectroscopy has been previously acknowledged as one of the most widely used techniques in the polymer industry for its characterization of polymers. Recently, FTIR has also been applied to evaluate the radiative thermal properties of several types of foams. According to Glicksman, the changes of the infrared intensity through polyurethane foams can be measured with FTIR to even determine thermal properties of polymer compounds. The main function of FTIR is to analyse the composition of a substance. The working theory is simple where the tested compound is exposed to infrared rays and the chemical bonds between the molecular
22
structures of the compound will absorb different amount of ray and this is represented as the wavelength of absorbance. Using this wave length and the intensity of absorption, the functional group which is present in the compound can be determined. The analysis for protective polymer coating is as below. Transmittance represents the intensity of the compound and the wave number is the wavelength absorbed by the molecular b onds. (cited from the journal “Measurement of radiative and chemical composition of polymer flims using FTIR” by Huijun Wu, Jintu Fan,
2007)
Figure 2.3: FTIR analysis Peaks
Differential screening calorimeter (DSC) and Thermogravimetry Analysis (TGA) is another common polymer characterization method. DSC is used to reveal the effects of different blending ratios on their melting and crystallinity behaviour and thermogravimetry (TGA) to reveal the degradation characteristics of the blends in terms of their induction time. According to A.C. Wong and Lam on their journal titled “Study of selected thermal characteristics of polypropylene/polyethylene binary blends using DSC and TGA” the blend ing of different polymer will have
effects on the thermal properties of the mixture i.e. difference in melting point 23
temperature, crystalline temperature and thermal degradation properties. This can be analysed easily using DSC and TGA. A thermo-gram with peaks representing the melting point properties and crystalline properties will be generated by DSC analysis.
Figure 2.4: DSC
analysis peaks
From the figure, the Tm represents final melting temperature and the Tcp represents the crystalline temperature. Using this test we can compare how the melting point varies with different compositions of blending. The weight loss of a polymer as a function of time or temperature is commonly determined by the technique of TGA. Weight loss of a polymer due to thermal degradation is an irreversible process. This thermal degradation is largely related to oxidation whereby the molecular bonds of a polymer are attacked by oxygen molecules. The data will be represented as the figure below. The part a) in the figure represents percentage of weight loss of the compound at different temperatures and the peak represents the temperature where a specific compound is oxidised.
24
Figure 2.5: TGA Analysis diagram
Water absorption test is another common test conducted on polymers to observe their water absorption properties. As a rule of thumb, it is desired in plastic industry that plastic manufactured exhibits a low water absorption property. This is. According to Han-Seung Yang’s journal “Water absorption behaviour and mechanical properties of lignocellulosic filler–polyolefin bio-composites” having a bio-filler increases the
the tensile strength of the composite produced but under the presence of moisture, the tensile strength reduces significantly. The water absorption test is conducted by immersing the composite in water for 24 hours and by calculating the water intake and later tested for tensile testing.
2.7 Conclusion
As a conclusion, multiple articles have been reviewed and discussed ranging from the researches that have been conducted with marine algae, LDPE as a matrix, possible ways of structural modification and also ways of blending. Hence further
25
research on these explained fields will produce conclusive evidence on the method selection to run the research on producing bio-plastic via marine algae. As from the literature review melt blending is decided to be the effective option to produce the LDPE and marine algae plastic blending. It is believed that this research will be able to further induce other researches on utilizing marine algae as a source of efficient adhesive material with elevated mechanical property.
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CHAPTER 3
Methodology and Materials
3.1 Introduction
This experiment is conducted by experiment where red algae are used as biofiller to produce plastic blend with LDPE. This particular species of algae is harvested and shipped from Semporna, Sabah. The main aim is to produce a good plastic sample using using thermo plastic as as well as thermo mechanical mechanical processing processing to produce the plastic. In this way off processing the the treated marine algae algae is blended with Low Density Poly Ethylene is blended using twin screw for superior blending to obtain highly homogenised plastic-algae composite composite in a wire like form. Apart from that, hot press is used to mould the produced sample into dog bone shape for further testing i.e. tensile testing and water water absorption testing. These methods are are simple and effective in plastic formulation in lab scale and testing purposes.
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3.2 Processing Flowchart
Pre-Treatment of marine algae
Algae is vigorously washed with continuous stream of warm water
Algae dried at 60 for 48 hours
Algae is the grinded using cutter mill, sieved and stored
The treated algae and LDPE pallets are weighed according to the blending ratio
Blending Process is done in twin screw extruder at 130 and 50 rpm screw speed
Extruded plastic is the palletized using the standard palletiser
28
Palletised sample is the moulded into dog bone shape using hot press
Samples are sent for testing and step 5 to 9 is repeated for all the different blending ratios set set
3.3 Materials
1. Red Marine Algae
2. Low Density Poly Ethylene
3.4 Equipment
1. Twin Screw Extruder 2. Hot Press 3. Fourier Transform Infrared Spectroscopy (FTIR) 4. Differential Screening Calorimeter (DSC) 5. Thermo-gravimetric Analyzer (TGA) 6. Tensile Tester
29
3.4.1 Extruder
To fabricate the plastic in this research, a twin screw extruder branded thermo Scientific was used. The extrusion process is done whereby the feed materials in this case the palletized LDPE and treated marine algae is fed through the feed hopper according to the ratio set where it is heated and homogenized by the twin screws present inside the extrusion barrel. Twin screw extrusion is used mainly for its superior homogenized mixing feature to help evenly distribute the algae bio-filler evenly throughout the LDPE matrix which is being extruded. The extruder is fitted with a standard palletizer where the extruded plastic is cut to standard palletized form.
Figure 3.1: Thermo Scientific Extruder
3.4.2 Hot Press
Hot pressed is used to mould the produced plastic into dog bone shape for tensile testing and water absorption test. This is done by pressing the sample under 1 atm pressure at 140 for 45 mins.
30
Figure 3.2: Hot Press
3.4.3
Fourier Transform Infrared Spectroscopy (FTIR)
FTIR is used to identify unknown materials, to determine quality or consistency of a sample and ultimately identify the components in the tested material. The FTIR works in a way where infrared rays are emitted onto the sample and the sample will absorb a certain part of the ray. Using this, the component is identified via the wave number it absorbs.
3.4.4 Differential Screening Calorimeter (DSC) and Thermo-gravimetric Analyzer (TGA)
DSC and TGA are used to analyze the thermal properties of the plastic blend produced. DSC will be used to determine the melting point and the crystallizing temperature of the plastic sample. This is done using the heat-cool-heat method 31
where the sample will be heated to 120 and then cooled down to 40 . The data obtained will be used to compare the varying trend of melting point and crystallizing temperature with increasing composition of marine algae.
Figure 3.3 DSC Machine
TGA on the other hand is used to observe the thermal degradation of the plastic sample with increasing temperature. The sample is heated up to 600 with a ramping rate of 20 per min. the results obtained can be used to study what components are degrading first with the present temperature.
32
Figure 3.4 TGA Analyser
3.4.5 Tensile Tester
Tensile tester is used to determine the strength of the plastic produced. After the dog bone shaped sample is fabricated, tensile testing is done to to identify the strength of the material produced. The Instron Tensile Tester with load of 50 KN is used. The elongation at break in percentages is also measure and recorded
3.5 Method of Research
3.5.1 Sample Preparation and Procedures
200g of sample is to be produced for every blending ratio. Therefore the composition of the compounds to be mixed is as follows: 33
Table 3.1: blending composition of samples in %
LDPE %
Algae %
100 95 90 85 80
0 5 10 15 20
Mass of LDPE (g) 200 190 180 170 160
and grams
Mass of Algae (g) 0 10 20 30 40
The sample with the above composition is weighed stored. These samples are than fed into the extruder to be blended. After a series of trial and error, it was found out that the best processing parameter is at 130 and 50rpm screw speed. After the samples are extruded, it is palletized using the standard palletizer to less than 5mm. After that, the samples are molded into “dog bone” shape using the hot press. Since the hot press parameters will significantly influence the tensile properties of the samples made, optimization is done by producing samples at different temperature and time and testing its tensile strength. Using the optimum temperature and pressing, all the samples are moulded. The samples are the analyzed with DSC, TGA, Tensile testing machine to find out the physical and thermal characteristics. Water absorption test was also conducted to analyze the water intake of the plastic sample made with increasing filler used. FTIR tests were also conducted to identify the functional group present in the plastic sample produced by thermo processing method.
34
CHAPTER 4
RESULTS AND DISCUSSION
4.1 Introduction
In this chapter all the characterization test results are compiled, reviewed and discussed to deduce if red marine can be utilized as prominent bio filler in producing plastic composite. The difference and similarities between all 4 algae samples with 5%, 10%, 15%, and 20% of algae and the pure LDPE sample will be analyzed. During the extrusion of the plastic blends, the operating conditions of the twin screw extruder were determined by trial and error. The samples were then palletized using standard palletiser to a length of 5mm. The palletized samples were then used to run DSC, TGA and FTIR. DSC and TGA were used to study the thermal properties of all 5 plastic samples (pure, 5%, 10%, 15%, and 20%). The results were then comparing to find out the relationship between how the algae filler composition influences the thermal properties. Also the samples were studied using FTIR to identify any changes in the molecular structure of the plastic/algae filler blending and the components present in it. Since different 35
bonds have different level of absorbance, it is common that each peak in the FTIR analysis shows a part of the molecule present in the compound. Tensile strength of the components was determined using the tensile testing machine. All 5 samples were molded into dog bone shape using hot press the tensile strength was determined by applying continuous force to the specimen until it breaks or rupture. Besides that the percentage of elongation at break can also be determined by observing the maximum displacement before rapture from the tensile test data. Apart from all these tests, water absorption test was also conducted to observe the how the water uptake varies with increasing algae filler in the composition. Theoretically, it is said that plastic blending with high water absorption properties are not suitable for moist condition as these material will show mechanical failure under wet conditions. Hence with that, a conclusion of whether red algae are suitable filler will be drawn.
36
Figure 4.1: Plastic Blend 5%, 10%, 15%, and 20% for top
left to bottom right
4.2 Extrusion Process
Optimization of twin screw extruder parameters were obtained by trial and error as mentioned above .The conditions of temperature were manipulated between 120 and 150 and finally the temperature of 130 was used as the sample fed into the extruder was easy to handle as it was extruded. The optimal points were decided based on physical observation of the extruded plastics appearance. It was found that at temperature of more than 130 , the algae filler start to disintegrate and burn. This situation is to be avoided as burned filler will influence the physical and mechanical properties of the plastic blend produced. The screw speed is also set to ease the process ability of the plastic blend and it was found the screw speed of 50rpm is the optimal screw speed to be used.
37
4.3 Hot Press: Parameter Optimization
Initially, the usage of injection moulding was to be used to make the dog bone shaped sample, but due to unavailability of the instrument, the experiment was improvised and hot press and mould was used instead to produce the tensile testing samples. Though there are 2 major draw backs of using this method, firstly the formation of air bubbles in the sample and secondly the sample made can be nonhomogenised. To solve this problem optimization of time and processing temperature is done. The optimization process was done by preparing 4 samples for of 1 plastic sample produce at different temperatures and another 4 samples at different pressing time. Then all the samples were tested for its tensile strength. The results of the data is as follows: Table 4.1: Hot Press Temperature optimization
Sample No 1 2 3 4
Temperature 120 130 140 150
Tensile Strength (N/mm) 5.8512 6.0501 6.6204 6.2042
38
Time (min) 30 30 30 30
Graph of Tensile strength vs Temperature 6.7 ) m6.6 m / 6.5 N ( / 6.4 h t 6.3 g n 6.2 e r t S 6.1 e l i s 6 n e 5.9 T 5.8 100
110
120
130
140
150
160
Temperature/ C̊
Figure 4.2: Graph of Tensile strength vs. Temperature
Table 4.2: Hot Press Time Optimization
Sample No 1 2 3 4
Temperature 140 140 140 140
Tensile Strength (N/mm) 5.2238 6.6204 6.463 6.0194
Time (min) 15 30 45 60
Graph of Tensile Strenght vs Time 6.8 ) 6.6 m m6.4 / N ( 6.2 / h t 6 g n 5.8 e r t S 5.6 e l i s 5.4 n e 5.2 T 5
y = 0.0149x + 5.5243 R² = 0.2114
0
10
20
30
40
50
60
Time/ min
Figure 4.3: Graph of Tensile Strength vs. Time 39
70
From the representation of optimization data above, the optimized temperature can be concluded is at 140 from the first graph and the time optimization is approximately 35 minutes. These conditions were applied to obtain the best results for strength of the plastic sample moulded. Assuring well-controlled processing parameters ensures less air bubbles formation and also better heat conduction for even melting and moulding of the plastic/ algae sample without burning the algae filler hence not decreasing the mechanical property. The moulded plastic is then cooled and stored to do maximum tensile testing.
Figure 4.4: Mould (top), Dog bone testing sample (bottom) 40
4.4 Differential Screening Calorimeter (DSC) and Thermo gravimetric Analyser (TGA)
In characterize the plastic blending produced, thermal properties of the plastics were analysed using DSC. The samples (Pure, 5%, 10%, 15%, and 20%) were analysed to obtain their melting point temperature and crystalizing temperature. The result of the analysis for the pure sample is as follows bellow and all the other curves is to be attached at the appendix.
Figure 4.5: DSC Profile for 5% of algae
41
In this diagram, the upper peak represents the crystalizing temperature or glass transition temperature of the sample. The lower peak represents melting point of the pure LDPE sample produced. Table 4.3: Glass Transition Temperature and Melting Temperature for DSC
Sample No
Composition of Algae (%)
1 2 3 4 5
0 5 10 15 20
Glass Transition Temperature Tg () 96.74 96.89 97.09 96.87 97.11
Melting Temperature () 107.08 105.67 106.24 106.36 106.42
Graph of Melting Point vs Algae Composition 107.2 107 106.8 / t 106.6 n i o 106.4 P g 106.2 n i t 106 l e M105.8 105.6 105.4
y = -0.0106x + 106.47 R² = 0.0275
0
5
10
15
20
Algae composition/ (%)
Figure 4.6: Graph of Melting Point
42
test
vs. Algae Composition
25
Graph of Glass Transition Temperature vs Composition 97.2 y = 0.0144x + 96.796 R² = 0.5247
97.1 ) 97 ( / g 96.9 T
96.8 96.7 0
5
10
15
20
25
Composition (%)
Figure 4.7: Graph of
Glass Transition Temperature vs. Algae Composition
Referring to figure above we can see that the melting point of the samples increase with increasing composition %. Though, the melting point of pure LDPE is somewhat higher compared to all the other samples. This is probably due to the fact that since there are no impurities in the pure sample, it’s likely that the bonds between the polyethylene molecules are retained. Introducing algae filler interfere with this bonding or creates an alternate bond with the polyethylene and breaks the polymeric structure of the overall molecular. The boiling point increases as more algae in introduced and more of these alternative bonds are created in its microstructure. The glass transition temperature however shows an overall increasing trend. The fluctuation of the Tg temperature can be due to some experimental error hence the fluctuated point can be assumed to be false. Taking that into consideration, the trend of Tg increases steadily with increasing composition percentage of algae.
43
Figure 4.8: TGA profile for
5% algae composition
TGA analysis on the other hand can be analyzed to study how the sample degrades with ramping temperature of 20
/
min up to 600. From the result, we
can observe that the degradation occurs at the 425-500 . We can conclude that the polymeric compound which is LDPE degrades at this range as the reduction in mass high decreases at the same temperature region. All the other composition exhibits the same trend accepts for algae with 20% composition.
44
Since the amount of algae in the 20% composite is becoming more significant, it is safe to say that the algae start to decompose first. This is because from the TGA analysis of 20% composition shows a slight decrease at the temperature region of 175 to 250. Hence it is safe to say that the algae decomposition temperature is at about 180.
Figure 4.9: TGA profile for
20% algae composition
4.5 Tensile Testing
Tensile test is done for all the samples using a ramping force method. The force is set at 10mm per min. Having done the test for all 5 samples which were produced under the optimized hot press parameters of 140 and 35min of pressing time, it was found out the material with composition of 10% had the best tensile strength among all the other composition but not surpassing the tensile strength of 45
the pure sample. The sample with 10% algae filler had tensile strength around 6.60 N/mm while the pure samples with no algae composition gives a tensile strength of 9.28 N/mm The testing data obtained is represented in the table below:
Table 4.4: Tensile Strength and Elongation at
Break profile for varying algae
composition Sample No
Composition (%)
1 2 3 4 5
0 5 10 15 20
Maximum Tensile strength (N/mm) 9.2811 6.6075 6.6204 6.0592 4.1805
Max Displacement (mm)
Initial length (cm)
37.384 15.848 20.918 11.376 5.0027
1160 1070 1320 1090 1030
Percentage of Elongation (%) 0.0322 0.0159 0.0151 0.0104 0.0040
Graph of Tensile Strength vs Composition ) 10 m m 8 / N ( / 6 h t g n 4 e r t S e 2 l i s n e 0 T
y = -0.215x + 8.6996 R² = 0.8673
0
5
10
15
20
Composition /(%)
Figure 4.10: Graph of Tensile Strength vs. algae composition
46
25
The tensile strength of the LDPE and algae blend exhibits lower mechanical properties than the pure LDPE sample. This is probably because the alga e’s
molecular structure did not bind or form bonds with the polyethylene structure causing it to be an isolated particle. These in terms serves as a point of rupture thus the bonding surrounding the algae grains are weak. Thus the plastic blended using algae as filler is weaker than that of the pure LDPE itself. But among the compositions with algae, the composition with 10% of algae shows best tensile strength. This is possibly due to the fact that 10% of algae composition is well homogenised as and better molecular bonds are established among the intermolecular structure of the polymer itself. As for the % of elongation, the trend below show that it decreases as the algae composition increases. This is because more algae filler makes the plastic made more brittle.
Graph of Elongation vs composition 0.035 0.03 ) 0.025 % ( n 0.02 o i t a g 0.015 n o l E 0.01
y = -0.0012x + 0.0279 R² = 0.8759
0.005 0 0
5
10
15
20
Composition (%)
Figure 4.11: Graph of
Elongation vs. Algae Composition
47
25
4.6 Water Absorption Testing
Water absorption test are done by soaking the moulded sample into water for duration of 24 hours. The amour of water absorbed is calculated in percentage to give a clearer picture. From the results obtained, we can conclude that increasing the composition of the algae increases the water absorbing ability of the plastic blended greatly, hence it has a poor water resistance property. The figure below shows the trend of water absorption with varying algae composition. Table 4.5: Water absorption profile with
varying algae composition
Sample
Composition (%) Initial Weight (g)
Final weight (g)
1 2 3 4 5
0 5 10 15 20
5.1188 8.3109 10.820 18.5103 22.638
5.0139 6.8466 6.9561 7.1779 7.4023
Water absorbance (%) 21 22.3 55.5 157.87 205.81
Graph of Water Absorbance vs Composition 250 ) 200 % ( e c 150 n a b r o s 100 b A r 50 e t a W 0
-50
y = 10.104x - 8.542 R² = 0.8948
0
5
10
15
20
Composition (%)
Figure 4.12: Graph of Water Absorbance vs. Composition
48
25
Hence we can conclude that using algae filler is not suitable for situation which involves high moisture thus limiting its application. Algae after absorbing the water will swell up and become mushy, thus it will decrease the mechanical properties of the blended plastic.
4.7 Conclusion
As a conclusion, after reviewing all the characterization of the algae and plastic blend produced from marine algae, we can conclude that it does not show a very promising potential as compatible filler with LDPE matrix. But the tensile strength obtained is fair as this material can be used for other purposes which does not involve high amount of force being applied to it.
49
CHAPTER 5
Conclusion and Recommendations
The characterization of the plastic blending produced that have been done via mechanical, thermal and physical testing will be used to draw a conclusion and answer our objectives of this research. In this research, we have discovered that the optimum processing parameter for the plastic blending sample in dog bone shape is at 140 and 35 min pressing time. The best composition was found to be 10% of algae blend where it exhibits the best mechanical property and other characteristics such as melting point, thermal degradation and other tests. However a lot of modifications and alternative polymer processing techniques must be applied to be able to commercialize plastic blends made out of marine algae. Hence without any modification, the red marine algae are not a suitable material to be used for plastic blending. The general trend shows with increasing composition of the algae, the tensile strength decreases. The water absorption property on the other hand increases drastically suggesting that plastic made from algae will have very weak performance under are with high humidity. The glass transition temperature also increases with increasing composition.
50
To improve the quality of the plastic blended using marine algae, the algae must first be treated or hydrolyzed to obtain the polymer extract i.e. carrageenan from the marine algae and use that as a blending resin instead of using it as a biofiller. This ways, the algae plastic can be homogenized easily and it will be more compatible other polymer matrix. The Agar which can be extracted from the red seaweed should also be studied as it possesses good bio-polymer properties. Journals suggest that agar can help slow down brittle properties of plastic materials produced while enhancing the effectiveness of binding agent. It also has a strong radio wave radiation resistance. Apart from that, chemicals such as coupling agents and binders can be used to test if it can help the bonding process of the molecular structure to make them stronger. Binders such as ethyl glycol should be used during the extrusion process to make sure superior blending. Injection molding should be used instead of compression molding. This is because injection molding will ensure a better dog bone sample without any air bubbles and uneven distribution of algae and matrix. This will enhance the tensile property of the plastic produce. Biotechnology techniques can play a very crucial role in making algae a viable source for plastic fillers or bio-polymers. This is because algae can be genetically modified and grown for specific purposes i.e. for polymer extraction.
51
Other researches can also be considered to be done with marine algae. Marine algae have an enormous water absorbing ability. This makes it a very weak plastic material in terms of conditions with moisture. Instead, this property should be embraced and researches should be done to produce super absorbent from marine algae’s instead. I believe algae will definitely excel in the prospect. Other than that,
the high protein ingredient contained by algae allows it to be researched to produce cosmetic products such as cream with anti-aging properties, hair nourishment shampoo and so on.
52
REFERENCES
Ali A. El Gamal, Biological importance of marine algae (2009) A.J.F. Carvalho a, A.A.S. Curvelo a, A. Gandini a , b , Surface chemical modification of thermoplastic starch: reactions with isocyanates, epoxy functions and stearoyl chloride (2004) Antonio J.F. Carvalho a,*, Marcia D. Zambon b, A. Aprigio da Silva Curvelo b, Alessandro Gandini , Thermoplastic starch modification during melt processing: Hydrolysis catalyzed by carboxylic acids (2005) Bhupinder Kaur, Fazilah Ariffin, Rajeev Bhat, Alias A. Karim,Progress in starch modification in the last decade ( 2011) Gholamhassan Najafia,, Barat Ghobadiana, Talal F. Yusaf b, Algae as a sustainable energy source for biofuel production in Iran: A case study (2010) Joo Ran Kim, Suraj Sharma, The development and comparison of bio-thermoset plastics from epoxidized plant oils, ( 2011) K. Vijayaraghavan a, J. Jegan b, K. Palanivelu c, M. Velan a, Biosorption of copper, cobalt and nickel by marine green alga Ulva reticulata in a packed column, (2005) Omar Faruk, Laurent M. Matuana, Nanoclay reinforced HDPE as a matrix for wood plastic composites, ( 2008) Rachele Pucciariello*, Vincenzo Villani, Carlo Bonini, Maurizio D’Auria, Teresa
Vetere, Physical properties of straw lignin-based polymer blends (2004) Ratih Pangestutia, Se-Kwon Kima,b, Biological activities and health benefit effects of natural pigments derived from marine algae (2011) Vikto´ ria Vargha a,*, Patricia Truter, Biodegradable polymers by reactive blending trans-esterification of thermoplastic starch with poly(vinyl acetate) and poly(vinyl acetate-co-butyl acrylate (2005) Worawan Pechurai, Charoen Nakason _, Kannika Sahakaro, Thermoplastic natural rubber based on oil extended NR and HDPE blends: Blend compatibilizer, phase inversion composition and mechanical properties, (2008)
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Appendix A: Gantt Chart Appendix B: Differential Screening Calorimetric Analysis Appendix C: Thermo-Gravimetric Analysis
54
APPENDIX A
Undergraduate Research Project 1 Gantt Chart
FEB
MARCH
APRIL
MAY
NOV
DEC
Brainstorm Deciding Title Plan Work Research Topic Search Literature Chapter 1 Chapter 2 Chapter 3 Abstract Presentation Submission Of Draft Proposal Submission
Undergraduate Research Project 2 Gantt Chart
SEPT
OCT
Material Order Application for Equipments Plan Work Run Experiment Search Literature Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Abstract Presentation Submission Of Draft Report Submission
55
APPENDIX B
DSC Analysis Results
5% algae composition DSC result
56
10% algae composition DSC result
57
15% algae composition DSC result
58
```
20% algae composition DSC result
59
APPENDIX C
TGA Analysis Results
TGA analysis for pure LDPE
60
TGA analysis for 5% algae composition
61
TGA analysis for 10% algae composition
62
