Table of Contents Chapter 1 .............................................................. .................................................................................................................................... .............................................................................................. ........................ 1 Chapter 2 .............................................................. .................................................................................................................................... .............................................................................................. ........................ 3 2. Introduction ....................................................................................................................................... .................................................................................................................................................... ............. 3 2.1 Bandages ............................................................... ..................................................................................................................................... ................................................................................... .............3 2.1.1 Rolled gauze bandages .................................................................................................................... ...................................................................................................................... .. 3 2.2 Materials ........................................................................................................................ ................................................................................................................................................... ........................... 4 2.2.1Traditional materials ............................................................. .......................................................................................................................... .............................................................4 2.3 Banana Fibre ....................................................................................................... ............................................................................................................................................. ......................................4 2.3.1 Introduction ....................................................................................................................... ....................................................................................................................................... ................ 4 2.3.2 Characteristics of Banana Fibres ................................................................. ....................................................................................................... ......................................4 2.4 Production P roduction of Rolled Gauzed bandages ................................................................................................... ................................................................................................... 5 2.4.1 Fibre extraction ................................................................................................................................. ................................................................................................................................. 5 2.4.2 Softening treatments carried c arried out on Banana fibres .......................................................... .......................................................................... ................6 2.4.3 Banana Fibre cutting Process ........................................................... ............................................................................................................ .................................................7 2.4.4 Spinning of Banana fibres ................................................................. .................................................................................................................. .................................................8 2.4.5 Winding process ................................................................................................................................ ................................................................................................................................9 2.4.6 Warping process ........................................................................................................ .............................................................................................................................. ......................10 2.4.7 weaving ............................................................................................. ............................................................................................................................................ ............................................... 11 2.4.8 Finishing ............................................................................................................................. ........................................................................................................................................... .............. 15 2.4.9 Testing ............................................................ ............................................................................................................................... ................................................................................. ..............16 Chapter 3 .............................................................. .................................................................................................................................... ............................................................................................ ......................22 3. Conclusion ................................................................... ......................................................................................................................................... ................................................................................. ...........22 4. References .................................................................................................................................................... ....................................................................................................................................................23
Chapter 1 Most of us are familiar with gauze rolled bandages from our childhood. These bandages are normally used to dress the wounds and demand is also high throughout the world. They directly placed on to wounds to control bleeding, to absorb secretions or to prevent contamination by bacteria or foreign material such as dirt. Nowadays cotton, silk and viscose is used to make these bandages globally. I have come up with banana fibre which is a cellulosic, natural, bast fibre to produce gauze rolled bandages. For dressing purpose banana fibre can fulfil the requirements and properties and it is available from many countries, eco-friendly and cheap. The preparatory process are lesser than the other fibres, therefore it is economical for making bandages. In Chapter 2 I have mentioned the manufacturing process of banana gauze rolled bandages including the process of extraction of banana fibre, cleaning, softening, cutting, spinning, winding, warping, weaving and finishing. For final product there is no need of dyeing. We can directly use them as griege fabric with some finishing.
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Banana fibre extracts from it's stem
Extraction
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Cleaning and softening
Sodium Hydroxide (NaOH) treatment removes impurities from the fiber surface and softens the fibre
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fibre strands cut into staple staple fibre length of 3 cm
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Open-end spinning method is used
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direct warping is used to make beams
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Narrow fabric weaving method is used
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Required finishing methods are used
Cutting
Spinning
Winding and warping
Weaving
Finishing
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Product Description A low cost banana fibre gauze rolled bandage Target Market Medical schools and Hospitals Secondary markets Pharmacies and houses The main challenges 1. Due to lack of awareness of banana fibre, most of the people can argue the product’s capability 2. No popular products which are made by banana fibre. So need a marketing strategy 3. Initial cost of the machines for fibre cutters and fibre extraction is high. 4. There is no proper market for banana fibre in Sri Lanka 5. Need more information about banana fibre, therefore a test research is essential 6. Medical textile; the new arrival may get lower response in the medical industry Improvements Banana fibre can blend with cotton, jute and viscose fibres to enhance the properties which are already have. Nowadays for medical textile only sanitary napkins are having banana fibres, therefore to apply gauze rolled bandages on wounds the testing facilities need to improve. As far there are no disadvantages of banana fibre in medical textile.
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Chapter 2 2. Introduction Textiles are not only used in the manufacture of traditional clothing and household uses; but also they have been used for thousands years in some engineering applications. The new generation of high-performance and high-functional fibres help the design engineers to tailor their products for special uses. The main purpose of this paper is to find an economic solution for using the banana yarns in the weaving process. In this research a production method to facilitate the weaving of medical bandages on a narrow weaving machine by supporting the yarns with banana fibres. This medical bandage will be used on the wound, where moisture and liquid that exude from the wound are absorbed by the fibrous structure to promote healing in relat ively dry conditions. 2.1 Bandages Bandages are one of the non-implantable materials; that are designed to perform a whole variety of
specific functions depending upon the final medical requirement. Bandages are widely used for external applications on the body with or without skin contact for medical, health care, athletic sports and clinical use. Bandages fabrics can be woven, knitted, or nonwoven and are either elastic or non-elastic. The most common applications for bandages are to hold dressing in place over wounds. Such bandages include lightweight knitted or simple open weave fabrics made from cotton or viscose that cut into strips then scoured, bleached, and sterilized. These medical bandages, gauze bandages like rolled bandages are used for different types of cuts, injuries, wounds etc. 2.1.1 Rolled gauze bandages These medical gauze bandages, like rolled as illustrated in below figure are used for different types
of cuts, injuries, wounds etc. Strong and convenient, these bandages are used when moderate compression is required. White open woven bandages have not elastic and has loose weave to give good ventilation, and are ideal for wound care as they do not constrict wounds. These bandages are woven by using cotton yarns count 40’s cotton.
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2.2 Materials Fibres used in health-care and surgery may be classified depending on whether the material from
which they are made are natural or synthetic, biodegradable or non-biodegradable. These fibres must be non-toxic, non-allergenic, and non-carcinogenic and must be able to be sterilized without imparting any change in their physical or chemical characteristics. 2.2.1Traditional materials Traditionally, natural fibres such as cotton, silk and later the regenerated cellulosic fibres (viscose
rayon) have been extensively used in non-implantable materials and healthcare/hygiene products. A wide variety of products and specific applications utilize the unique characteristics that synthetics fibres exhibit. Ordinary viscose rayon is widely used for disposable cleaning and hygiene products, for its good temperature resistance and absorbency, it is also sensitive to the effect of moisture. 2.3 Banana Fibre 2.3.1 Introduction Banana plant is not only gives the delicious fruit but also provides textile fibre. Banana fibre, a
ligno-cellulosic fibre, obtained from the pseudo-stem of banana plant (Musa sepientum), is a bast fibre with relatively good mechanical properties. It grows easily as it sets out young shoots and is most commonly found in hot tropical climates. All variety of banana plants has fibre in abundance. These fibres are obtained after the fruit is harvested and fall in the group of bast fibres. After the fruit production, the trunk of the plant is thrown as agricultural waste to a great extent. These stems can be effectively utilized in production of the banana fibres. Biomass waste, a rich source of natural fibres can be profitably utilized for numerous applications and preparation of various products. Natural fibres present important advantages such as low density, appropriate stiffness and mechanical properties and high disposability and renewability. Moreover, they are recyclable and biodegradable. There has been lot of research on use of natural fibres in reinforcements. Banana plant is a large perennial herb with leaf sheaths that form pseudo stem. Its height can be 10-40 feet (3.0-12.2 meters) surrounding with 8-12 large leaves. The leaves are up to 9 feet long and 2 feet wide (2.7 meters and 0.61 meter). Banana plant is available throughout Thailand and Southeast Asian, India, Bangladesh, Indonesia, Malaysia, Philippines, Hawaii, Sri Lanka and some Pacific islands. 2.3.2 Characteristics of Banana Fibres Banana fibre has its own physical and chemical characteristics and many other properties that make
it a fine quality fibre. 4
Appearance of banana fibre is similar to that of bamboo fibre and ramie fibre, but its fineness and spinnability is better than the two.
The chemical composition of banana fibre is cellulose, hemicellulose, and lignin.
It is highly strong fibre.
It has smaller elongation.
It has somewhat shiny appearance depending upon the extraction & spinning process.
It is light weight.
It has strong moisture absorption quality. It absorbs as well as releases moisture very fast.
It is bio- degradable and has no negative effect on environment and thus can be categorized as eco-friendly fibre.
Its average fineness is 2400Nm. Nontoxic and odour free fibre. It can be spun through almost all the methods of spinning including ring spinning, open-end spinning, bast fibre spinning, and semi-worsted spinning among others.
2.4 Production of Rolled Gauzed bandages 2.4.1 Fibre extraction The extraction of the natural fibre from the plant required certain care to avoid damage. In the
present experiments, initially the banana plant sections were cut from the main stem of the plant and then rolled lightly to remove the excess moisture. Impurities in the rolled fibres such as pigments, broken fibres, coating of cellulose etc. were removed manually by means of comb, and then the fibres were cleaned and dried. This mechanical and manual extraction of banana fibres was tedious, time consuming, and caused damage to the fibre. Consequently, this type of technique cannot be recommended for industrial application. A special machine (Fig. 2) was designed and developed for the extraction of banana fibres in a mechanically automated manner. It consisted mainly of two horizontal beams whereby a carriage
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with an attached and specially designed comb, could move back and forth. The fibre extraction using this technique could be performed simply by placing a cleaned part of the banana stem on the fixed platform of the machine, and clamped at the ends by jaws. This eliminated relative movement of the stem and avoided premature breakage of the fibres. About 37 kg (average weight) of stem yields about 1 kg of good quality fibre. The yield is about 1-1.5% of dry fibre. The fibre obtained from the central core is of lower quality. The fresh banana plant yields about 0.61.0% of fibre, depending on the variety and method of extraction used. The below table 2 is showing the production capacity per hour in tons.
This was followed by cleaning and drying of the fibres in a chamber at 200 C for three hours. 2.4.2 Softening treatments carried out on Banana fibres 2.4.2.1 Softeni ng of banana f ibr es thr ough A lkal i treatment
Sodium Hydroxide (NaOH) treatment removes impurities from the fibre surface, Banana fibre sample were treated with three different conc. of NaOH to soften the fibre and make it suitable for spinning. The concentrations used were 0.5%, 1%, 1.5% weight/volume. Treatment was done with sample: liquor ratio of 1:30.Standard procedure used in the institute is as follows.
2.4.2.2 Al kal i ne treatment of ban ana f ibr es
Protocol: 1. Weigh out the quantity of banana fibres 2. Check out specific gravity of required conc. Of NaOH 3. Take NaOH solution (1:30 ratio) 4 gm fibre: 120 ml NaOH 4. Add wetting agent i.e. auxypon192 5. Mix the solution properly 6. Add fibres in a mixed solution such that fibres ar e immersed in the solution completely 6
7. Keep it for ½ hr. Swirl the solution intermediately 8. Wash out the fibres with warm water 4-5 times 9. Keep the fibres in 0.1% acetic acid solution (1:30) for 2-4 min 10. Wash the fibres with water 11. Dry the fibres at room temperature. 2.4.2.3 Preparation of N aOH soluti on
Since the MLR used was 1:30 total solution used in each case was 6 litres. For preparation of NaOH solution, 5% NaOH solution was used. Below Table is showing the preparation of NaOH solution using 5% solution 5% NaOH Solution -5gm in 100 ml D/W
2.4.3 Banana Fibre cutting Process 2.4.3.1 Ban ana staple fi bre cutti ng machi ne
This machine has 2/2 calendar rollers for holding the fibre while cutting. There are two blades one Stationery and oscillating for cutting the fibre. At present t he banana fibres are cut in the range of 3 to 20 cm. Provision is also made in the machine to change the cut lengths depending up on the requirement by changing the gears.
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2.4.4 Spinning of Banana fibres 2.4.4.1 Open-end spin ni ng of Ban ana f i bres
The input fibre strand is a drawn sliver. A sliver may have more than 20,000 fibres in its crosssection. This means that a yarn of 100 fibres per cross-section will require a total draft of 200. Drafting in rotor spinning is accomplished using a comber roll (mechanical draft) which opens the input sliver followed by an air stream (air draft). These two operations produce an amount of draft that is high enough to reduce the 20,000 fibres entering the comber roll down to few fibres (5-10 fibres). In order to produce a yarn of about 100 fibres per cross-section, the groups of few fibres emerging from the air duct are deposited on the internal wall of the rotor and a fibre ring is formed inside the rotor. The total draft in rotor spinning is, therefore a combination of true draft from the feed roll to the rotor (in the order of thousands) and a condensation to accumulate the fibre groups into a fibre ring inside the rotor. The total draft ratio is the ratio between the delivery or the take-up speed and the feed roll speed. This should approximately amount to the ratio between the number of fibres in the sliver cross-section and the number of fibres in the yarn cross-section.
Consolidation in rotor spinning is achieved by mechanical twisting. The torque generating the twist in the yarn is applied by the rotation of the rotor with respect to the point of the yarn contacting the rotor navel. The amount of twist (turns per inch) is determined by the ratio between the rotor speed (rpm) and the take up speed (inch/min). Every turn of the rotor produces a turn of twist, and a removal of a length of yarn of 1/tpi inches.
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2.4.4.2 Speed I nterr elati onshi p
Normal & maximum revolutions & speeds are Rpm of opening roller: 5000 -10000 rpm Rpm of rotor up to 100000 rpm Delivery speed: up to 200m/min. 2.4.4.3 Techni cal Data of Rotor Spin ni ng M achi ne
Number of spinning positions per m/c
up to 220
Count range
12- 125 Tex (5 – 50 Ne)
Draft
25- 400
Speed of rotation of opening roller
6000- 11000 rpm
Rotation speed of rotor
up to 120000 rpm
Rotor diameter
32 -65 mm
Delivery speed (m/ min)
up to 200
Package mass
up to 5 kg
Angle of taper
2° - 4° 20’
Winding angle
29° – 45°
The below flow chart shows open end spinning method.
2.4.5 Winding process Most of the textile winding operations deal with the conversion of ring frame bobbins into cones or
cheeses. One ring frame bobbin (cop) typically contains around 100 grams of yarn. If the yarn count is 20 tex, then the length of yarn in the package will be around 5 km. As the warping speed in modern machines is around 1000 m/min, direct use of ring frame bobbins in warping will necessitate package change after every 5 minutes. This will reduce the running efficiency of 9
warping machine. Therefore, ring frame bobbins are converted into bigger cones (mass around 2 kgs or more) or cheeses.
2.4.6 Warping process In ribbon weaving, warp beams are generally produced according to the below diagram. As the
thread count is usually low, the warp bobbins can be produced in a direct process. Threads are drawn through the bobbin creels. After being tensioned and going through inlet comb (eyelet), yarns pass through a yarn tension regulator. Then they pass through a cross-laying reed, anti-static equipment, the spacing reed and guide roller. Then yarn is when wound onto a warp beams as sections.
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2.4.7 weaving To make gauze rolled bandages gauze weave is used. In gauze weave weft yarns are encircled by
tow warp yarns twisting around each other, a construction that gives strength although the mesh is open.
The two warp ends are called as standard and crossing (doup) which are frequently come from separate warp beams. If both standard and crossing ends are warped on to one beam the same length of warp is available for both and they will have to do the same amount of bending, that is they will 11
have the same crimp. Such a fabric is shown in plan view and cross section in below figure (a). if the two series of ends are brought from separate beams the standard and crossing ends can be tensioned differently and their crimp can be adjusted separately. In such case it is possible for the standard ends to lie straight and the crossing ends to do all the bending. Such a fabric is shown in below figure (b)
2.4.7.1 M echan ism of gauze weave
Doup thread―also called crossing thread, during the weaving process, the doup thread are raised in each shed, and it passing each time under the standing threads forms a zigzag line.
Standard or regular thread―during weaving, it remains comparatively straight.
Standard shaft ― the shaft is same as conventional shaft.
Doup shaft ― also called lifting heald. 12
Lifting healds L1 and L2 consist of two individual flat steel strips. Close to their centre they are connected to each other to form a resting point (:) which is necessary for the lifting of the doup heald D. Doup heald shanks slide between the steel strips. The bottom end of each shank is fitted with a carrying rod. These two rods are connected to each other at their end by stoppers and constitute the doup heald frame. 2.4.7.2 Weaving M echani sm
Two kinds of warp threads are necessary: standard ends and doup ends. The doup end is drawn into the heald of the ground shaft LG and into the eyelet of the doup heald D. The standard end is drawn into the heald of standard shaft S and between the spaces of the lifting healds. The doup heald frame with the lifting heald shaft is fitted at the front. Gauze ground shaft LG and standard shaft S are placed with a gap of approximately 8-12 cm behind the doup heald frame. This space is necessary to allow for a reasonable formation of the crossed shed. The mechanism of shedding system of gauze or leno can form three shed as following
① Plain shed. ‘ Only the standard end is raised by the standard shaft S. Shafts LG, L1 and L2 with doup heald frame remain lowered. This plain shed forms part of the ground weave. It is used for leno weaves.
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② Open shed The doup end is raised by shafts LG and L2 with doup heald D on the right side of the standard end. Shafts L1 and S are lowered. This open shed forms the other part of the ground weave. Standard ends have free passage between the upper part of L1 and the raised doup heald D. See Fig. 9.1, gauze weave weft ① can be woven by this shed.
③ Crossed shed. The doup end raised by shaft L1 with doup heald D on the left hand side of the standard end. Shafts L2, LG and S are lowered. See Fig.9.1, gauze weave weft
② can be woven by this shed.
We can use Air jet weaving machine to produce gauze weaves and the specifications are,
Reed space: 230cm motor power: 1.5kw Weft density: 10picks/cm Speed: 600r/min Shedding: cam take up: mechanical Let -Off: mechanical Cutter: mechanical Linear Yards/Hour = (600picks per min. / 25.4picks per in.) x (60 min. per hr. / 36 in. per yd.) x .92 loom efficiency Linear Yards/Hour = 36.22 yards/ hour Rate of Filling Insertion (Meters/Min) = 600(Picks/Min) x 2.3 (Meters) x .92 Loom Efficiency Rate of Filling Insertion (Meters/Min) = 1269.6 m/min 14
2.4.8 Finishing 2.4.8.1 Bi o poli shi ng
This is a process to remove the protruding fibres of a fabric through the action of an enzyme. This enzyme selectively acts on the protruding fibres and cease to work after finishing the work by a simple raise in temperature of the treatment bath. Bio polishing of the banana/jute blended fabrics after scouring was carried out using 1% cellulolytic enzyme owf, a proton based chelating agent 0.5% owf, at 55 deg C and pH 5.5-6 for 60 minutes keeping the material to liquor ratio 1:10. After the treatment the temperature of the bath was raised to 90 deg C for deactivation of the enzyme and maintained at that temperature for 15 minutes. The samples were then washed in cold water and then dried. BIOLASE FCE (N) = 1% SIRRIX 2 UDI = 0.5%. MLR: 1:0. pH = 5.5-6. Temperature = 55deg C. Time = 1hr. 2.4.8.2 Softeni ng
This was carried out using the dip method due to very good pick up properties of the fabric. A cationic softener 20g/L, Acetic acid 0.5g/L, MLR 1:10 was followed by drying at room temperature and curing at 180 deg C for 2minutes.Softening was also carried out using a combination of micro amino silicone-based softener 20g/L and a macro-emulsion based silicone product 10g/L applied through padding technique with a pH of 5.5 and material to liquor ratio 1:10 followed by air drying and curing at 150 deg C for 3 minutes. LEOMIN PNLI = 3%. Acetic acid = 1.5 %. MLR: 1:10. Temperature = 60 deg C. Time = 30 mins. 2.4.8.3 Resin tr eatment
A wax based cross-linking agent 30 g/L was applied through padding technique at pH5.5 and MLR 1:10. The fabrics after padding were air dried and cured at 180 deg C for 2 minutes.
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Application = Padding technique. ARKOFIX NEC PLUS = 20 g/l. CERALUBE HD = 15 g/l. SOLUSOFT MW =10 g/l. Mgcl2 = 6 g/l. MLR: 1:10 pH = 5.5. DIP METHOD: CERALUBE JNF = 30g/l. CERAPERM 3-P-PLUS = 20 g/l. MLR: 1:10. pH = 5.5. 2.4.8.4 H andle fi ni sh
An aqueous polyurethane dispersion 100g/L was also used for finishing the banana/jute blended fabrics keeping the material to liquor ratio 1:10, pH 5.5 - 6 and was applied through padding technique and air dried and finally cured at 150 deg C for 3 minutes . 2.4.9 Testing 2.4.9.1 Deter mi nati on of th e (sti f fn ess) bendi ng l ength of th e fabr i cs
The stiffness of the fabric was measured in accordance with the Standard IS: 6490-1971.The principle employed is to measure a particular length of the fabric specimen of specified dimensions which when used as a cantilever bends to a constant angle under its own weight. Bending length equals half the length of rectangular strip of fabric that will bend under its own weight to an angle of 41.5º. It is also equal to the length of a rectangular strip of materials that will bend under its own weight to an angle of 7.1º. It is expressed in centimetres. Rectangular warp way and weft way test specimens of 25×200 mm size preferably with the help of template from different portions of the fabrics were cut after the fabrics were conditioned for at least 24 hours. The tester is placed on a table and inclined reference line is at eye level and the platform is adjusted accordingly so that it is horizontal in position. Place one of the specimens on the platform with the scale on top of it length wise and the zero of the scale coinciding with the leading edge of the specimen. Holding the scale in the horizontal plate, specimen is pushed along with the scale slowly and steadily when the leading edges project beyond the edge of the platform. An increasing part of the specimen will overhang and start bending under its own weight. The pushing is stopped once the tip of the fabric reaches the 16
level of the inclined plane. The length of the overhanging portion is from the scale to the nearest millimetre. Four readings from each specimen with each side up first at one end and then at the other is noted. The average of the four readings for each test specimen is then calculated separately for both warp way and weft way specimens in the method mentioned below, Bending Length (C) = L÷2 cm. 2.4.9.2 Deter mi nati on of the wear an d tear
Abrasion which is one aspect of wear is caused by rubbing away of the component fibres and yarns of the fabric. Abrasion resistance of the fabrics in this study was carried out using Martindale Abrasion tester also called as Cloth rubbing or Wear testing machine. In this instrument the material is rubbed by the multidirectional movement of the specimen holders against the abrading surface. The multidirectional movement is achieved by the imposition of two simple harmonic motions at right angles to each other on the plate on which the specimen holders are fitted. Depending on the type of fabric to be tested, the roughness of the abrading surface and the load on the top of the specimen holder are decided. The experiment was carried out according to method described in the Standard, IS: 12673:1989. Four specimens of 38 mm (1.5 in.) diameter are cut and fixed on the four circular specimen holders which are mounted under desired load (30-125 g/cm2) on the brass plate subjected to multidirectional motion. The abrading paper or cloth is fastened to each of the four tables‘beneath, such that the fabrics mounted on the specimen holder rub uniformly against the abrading surfaces. The estimation of wear that has taken place (end point) is made in two ways, (1) visually, by noting the number of rubs required for the formation of holes in the fabric and (2) by determining the loss in weight of the fabric after the specified number of rubs as the initial weight of the fabric before mounting is recorded for finding out the loss in weight after the experiment. 2.4.9.3 Deter mi nati on of th e teari ng str ength
Tear resistance is the average force, in Newton‘s, required to tear a test specimen over a specified length. The tear strength of the fabrics is determined by the ballistic method employing the KMI tearing strength tester similar to the Elmendorf apparatus. The procedure followed was in accordance with the Standard IS: 6489-1993.This instrument measures the average force required to propagate a tear originating from a cut in the fabric. The rectangular test specimen having a specified pre-cut slit is mounted between clamps of the instrument, is subjected to a tearing force generated by the (energy stored) rapid swing of a sector shaped pendulum. The energy expended in tearing the specimen is used to determine the tearing resistance of the specimen. One of the clamps is fixed on the pendulum while the other is mounted on the frame of the instrument. With the pendulum in the raised position, the two clamps are aligned and the sample is punched out by a 17
cutting die and is clamped tightly. A knife on the frame is used to make a 20 mm (0.8 in.) slit in the specimen. When the pendulum is released, the fabric tears across its width from the end of the cut to the opposite edge through a distance of 43 mm (1.7 in.). The arc through which the pendulum swings is related to the energy consumed in tearing. The average force required for the tear, obtained by dividing the energy by twice the length of the tear, indicated on the scale. The readings were discarded when the specimen slips in the jaws or while tearing deviates beyond the base of the slit in such a way that the tear is not completed in the notch at the top of the specimen. Six specimens each from the warp and weft directions are tested and the average tearing strength in grams for the warp and weft directions are reported separately. 2.4.9.4 Deter mi nati on of the tensil e str ength
The methods used for determining the breaking strength is the ravelled strip method, which gives the breaking load required to rupture a specific width of fabric. It is particularly used for comparison of the effective strength of yarns in the fabric with their strength before weaving. The procedure followed was as per the mentioned Indian Standard IS: 1969-1985.Each specimen is cut with its width about 14mm (minimum 20threads) more than required width, and threads (minimum 10 threads) are ravelled out from both sides of the strip equally to reduce the width of the specimen excluding the fringes to the required level. The breaking load tests are carried out using the Good brand‘s Horizontal Cloth tester which is a CRT (Constant rate of Traverse) type of machine. A specimen size is 50 mm × 200 mm (distance between the clamps) with sufficient extra length of fabric on either side for holding it in the clamps is generally used. Six specimens are tested for each warp and weft directions. The rate of traverse used is 300 mm (12 in.) per min, with the usual tolerance of 15 mm (0.5 in.). The mean value of the breaking strength in each case is expressed in Kilogram‘s. Elongation at break can be easily obtained from the load -elongation graph recorded by the machine. 2.4.9.5 BS EN 13726-1 - A spects of Absorbency
The majority of wound dressings are applied to remove excess wound fluid (exudate) from the immediate vicinity of the wound. This standard contains a series of test methods which assess absorbency, fluid handling capacity and dispersion characteristics: Section 3.2 Free-Swell Absorptive Capacity This test is intended to measure the absorbency of fibre-type wound dressings such as alginates (e.g.
Kaltostat, Sorbsan etc.) and gelling fibres (e.g. Aquacel, Durafibre etc.) which are used on moderate to heavily exuding wounds where total absorptive capacity is an important feature.
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Dressings are sectioned into 5x5cm samples, weighed and then incubated in artificial exudate at 37°C. The free-swell absorbency following 30 minutes incubation is subsequently calculated. This test is only appropriate for dressings which remain physically intact and which reach their absorptive capacity within 30 minutes under the test conditions. As the dressings need to be sectioned prior to testing, this test method is not appropriate for superabsorbent containing wound dressings (SMTL have alternative test methods for super-absorbent wound dressings which are outlined in SMTL TM-404 and TM-414). Similarly, wound dressings which have duel action of handling exudate via absorbency and moisture vapour transmission are not appropriate for this test, and should be tested for Fluid Handling Capacity. Section 3.3 Fluid Handling Capacity This test is designed to measure the removal of exudate from the wound by wound dressings which
handle the exudate through absorbency and permeability (also known as moisture vapour transmission) e.g. foam and hydrocolloid wound dressings. Dressings are sectioned and applied to a Paddington cup (see image). Artificial exudate is introduced into the cup and a lid applied to form a closed system. The cup is pre-weighed and then incubated at 37°C. Following 24 or 48 hours incubation, the cup is weighed to calculate exudate handled via moisture vapour transmission.
The lid of the cup is
then removed and remnant exudate drained from the cup. The cup is then re-weighed to calculate the mass of exudate absorbed by the wound dressing. This test is only appropriate for waterproof wound dressings. Testing is often performed using a 72 hour incubation period for slow fluid handling wound dressings such as hydrocolloids.
Section 3.4 Fluid Affinity of Amorphous Hydrogels Amorphous hydrogels are designed so that they absorb or donate fluid depending on the
environment of the wound. This test measures the ability of the hydrogel to donate or absorb exudate when incubated in a relatively dry (gelatine) and moist (agar) environment respectively.
Section 3.5 Gelling Characteristics This test is designed to distinguish between fast and slow gelling fibre dressings when in the
presence of excess exudate. The formation of a gel between the dressing and the wound exudate
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can reduce adherence to the wound and helps create a moist environment. Knowledge about the rate of gelling can assist in selecting the most appropriate dressing for a particular wound. A sample of the dressing is grated and introduced to artificial exudate for 1 minute. The solution is then processed via a series of filtrations and the final residue examined for the presence of a gel. Section 3.6 Dispersion Characteristics This test is designed to distinguish between fibre wound dressings which readily lose integrity and
disperse, and those which stay intact. A sample of the dressing is placed into a flask with artificial exudate and gently swirled for 1 minute. The contents of the flask are then visually examined and an assessment made whether the dressing is dispersal (separation of fibres leaving no evidence of the original fabric structure) or non-dispersal dressing (clear evidence of the dressing original fabric structure).
Section 3.7 Dispersion/Solubility of Hydrogel Dressings This test is useful to determine the physical properties of amorphous hydrogels wound dressings in
the presence of copious quantity of exudate. Hydrogel is introduced into a stoppered flask containing artificial exudate and the flask shaken for 2 minutes to allow dressing dispersion/dissolution. The flask is then allowed to stand for 2 hours and then inspected and an assessment made whether the dressing is soluble (has dissolved into the test solution), dispersible (remains in two distinct phases or disperses to uniformly and then settles out to form two distinct layers) or if the dressing is a non-dispersal product (retains its original structure).
2.4.9.6 BS EN 13726-2 - M oistur e Vapour Tr ansmi ssi on Rate (M VT R) of Vapour Per meable F il m D r essin gs
MVTR forms an important part of the fluid handling properties of a dressing. It influences both the hydration of the wound and that of surrounding tissues where maceration may be a problem. This test is intended to be performed on wound dressings which handle wound exudate through permeability alone (e.g. film wound dressings) when:
Section 3.2 MVTR of a Wound Dressings When In Contact With Water Vapour Designed for wound dressings are not in direct contact with wound exudate. 20
Section 3.2 MVTR of a Wound Dressings When In Contact With Liquid Designed for waterproof wound dressings which are in contact with wound exudate. Dressings are
sectioned and applied to a Paddington cup. Artificial exudate is introduced into the cup and a lid applied to form a closed system. The cup is pre-weighed and then incubated at 37°C. Following 4 24 hours incubation, depending on the test method, the cup is weighed to calculate exudate handled via moisture vapour transmission.
2.4.9.7 BS EN 13726-3 - Waterpr oofn ess
The ability of a dressing to maintain a waterproof barrier is important to prevent possible transmission of bodily fluids into the wound. This test measures the ability of the outer surface of the dressing to act as a waterproof barrier under a hydrostatic pressure.
Dressings are sectioned and applied to test cell containing deionised water so that the outer surface of the dressing is in contact with the water. Filter paper is placed on the wound contact layer surface of the dressing and a hydrostatic head of 0.5 meters is applied to the test cell for 5 minutes. The filter paper is then examined for the penetration of water through the wound dressing.
2.4.9.8 BS EN 13726-4 Conf orm abil ity
Dressings that are applied around joints or to other areas of tissue subject to movement or distortion must, to some degree, accommodate this without causing excessive pressure, or in the case of adhesive products, shearing forces that can cause skin trauma. In this method the dressings are sectioned into 25mm widths and marks made on the sample 100mm apart (L1). The samples are then positioned within a tensometer then extended 20% and the maximum load recorded, so that the extensibility can be calculated (N per cm-1). The sample is held at this extension for 1 min, and then removed from the tensometer. The 2 marks on the sample are then re-measured (L2) and the percentage permanent set are calculated. Even though the EN 13726-4 is termed conformability, in reality this is an assessment of extensibility/permanent set test rather than an assessment of dressing conformability. Therefore the SMTL have developed other test methods to assess dressing conformabilit y. 21
Chapter 3 3. Conclusion Gauze rolled bandages made by banana fibre is a new development in medical textile. It will be popular if the government or private sector will t ake over the banana fibre industry. These bandages are economical as well as producible in an easy manner rather than having additional process of manufacturing like other fibre materials such as cotton and viscose. Banana fibres are hygienic and natural cellulosic fibre which can use for medical textile. The availability of banana fibre and facilities of manufacturing of bandages are situated in Sri Lanka therefore this product can be achieved in economical way to fulfil the medical purposes.
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4. References 1. Energy Conservation Drives for Efficient Extraction and Utilization of Banana Fibr, D.P. Ray1, L.K. Nayak2, L. Ammayappan3, V B Shambhu4, D Nag5. National Institute of Research on Jute & Allied Fibre Technology, 12, Regent Park, Kolkata, Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 3, Issue 8, Au gust 2013) 2. Web: http://www.smtl.co.uk/testing-services/54-wound-dressings-testing-services/127-primarywound-dressings.html, accessed on: 05/06/2016
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