EXPERIMENT 1
Condensation Polymerization
1.0
Objective:
To synthesize Nylon 6,6 via step-growth polymerization and to examine the physical properties of the polymer.
1.1
Introduction:
Condensation or step growth polymerization involves generally involve either one or more types of monomers. In either case, each monomer has at least two reactive (functional) groups. In the process, usually a small molecule such as water or ammonia, is eliminated.
In this experiment Nylon 6,6 is prepared by Interfacial Polymerizations using Polymerizations using a diamine (hexamethylenediamine) and a diacid chloride (sebacyl (or Sebacoyl) chloride).
H2N(CH2)6NH2
+
ClCO(CH2)4COCl
hexamethylenediamine
adipoyl chloride
The reaction is done in a two-phase system where the amine is dissolved in water, and the diacid chloride in an organic solvent. The two solutions are immiscible and the polymerizations take place at the interface where the diacid chloride and diamine meet.
Many diamines and diacids (or diacid chlorides) can be reacted to make other condensation products that are described by the generic name "nylon." The word "nylon" is used to represent synthetic polyamides. Nylons are one of the most common polymers used as a fiber. a fiber. The The various nylons are described by a numbering system that indicates the number of carbon atoms in the monomer chains. For example, nylons from diamines and dicarboxylic acids are designated by two numbers, the first representing the diamine and the second the dicarboxylic acid.
Nylon 6,6 is a long molecular chain with denser structure. It exhibits the highest melting point (256ºC) of all synthetic fibers. Therefore, it is the most heat and friction resistance and an excellent choice for making carpet, apparel, airbags, tyres, ropes, conveyor belts, hoses, etc.
1.2
Materials:
20% NaOH 5% aqueous solution of hexamethylenediamine, H 2N(CH2)6NH2 0.25 M adipolychloride in cylohexane 80% formic acid
1.3
Apparatus:
50 ml beaker Pipet Tweezers
1.4
Safety Precaution:
All work should be done in the hoods. Do not handle the nylon until it has been thoroughly washed. It may caused irritation to the skin, eyes and mucous membranes.
1.5
Procedure:
a) Add 2 ml of 20% NaOH solution and 10 ml of hexamethylenediamine in a 50 ml reaction beaker. b) Draw 10 ml of 0.25 M of adipoly chloride solution in cylohexane into a pipet and carefully layer this solution on top of the aqueous solution in the beaker. c) Leave the solutions for several minutes to allow the polymerizations to take place. d) Slowly lift and gently wind the nylon fiber obtain at the center of the two solutions. Tip the beaker slightly and continue to pull the fiber.
e) Wash the nylon thread thoroughly with water and let it dry on a clean paper towel. f)
Weigh your product of nylon 6,6.
g) Dissolve a small amount of nylon in 80% formic acid. Place a few drops of the solution onto a microscope slide and allow the solvent to evaporate under the hood. h) Observe and compare the structure of the nylon thread and the nylon film under a miscroscope
1.6
Data analysis:
a)
Describe the physical properties of the nylon thread.
b)
Compare the appearance of the solvent cast nylon film with that of the nylon thread.
c)
Compare the structure of the solvent cast nylon film with that of the nylon thread using optical microscope.
d)
1.7
Determine the molecular weight of your nylon thread.
Questions:
a) Give the structure of Nylon 6,6. and state the molecule that has been eliminated in the polymerization. b) Name the type of condensation polymerization for the preparation of Nylon 6,6. c) Suggest the monomer(s) for the polymerization of Nylon 6,10 d) Name the type of condensation polymerization for the preparation of Nylon 6. e)
i)
Draw the structure of a polymer obtained from the polymerization of sebacoyl chloride, ClCO(CH 2)8COCl and ethylene glycol, HO(CH 2)2OH.
ii)
What are the molecules that have been eliminated in this condensation reactions.
iii)
Classified the polymer obtained based on its interlinkage unit.
CHM 572 EXPERIMENT 2 REPORT SHEETS
Name :
Group Members :
1. 2. 3.
Date of Experiment :
2.0
Objective: Write the objective of the experiment:
2.1
Procedure: Summarized your procedure in a form of flow chart.
2.2
Results and Discussions:
a)
Weight of nylon 6,6 obtained = ______ g
b)
Describe the physical properties of the nylon thread.
c)
Compare the appearance of the solvent cast nylon film with that of the nylon thread.
d)
Compare the structure of the solvent cast nylon film with that of the nylon thread. Paste the optical micrographs of both nylon thread and nylon film.
e)
2.3
Determine the molecular weight of your nylon thread.
Conclusions: Conclude or give any comments on the results obtained from the experiment.
2.4
Questions:
a)
Give the structure of Nylon 6,6. and state the molecule that has been eliminated in the polymerization.
b)
Name the type of condensation polymerization for the preparation of Nylon 6,6.
c)
Suggest the monomer(s) for the polymerization of Nylon 6,10
d)
i)
Draw the structure of a polymer obtained from the polymerization of sebacoyl chloride, ClCO(CH 2)8COCl and ethylene glycol, HO(CH 2)2OH.
ii)
What are the molecules that have been eliminated in this condensation reactions.
iii)
Classified the polymer obtained based on its interlinkage unit.
