1. SYNTHESIS AND ANALYSIS OF COMMERCIAL POLYMERS
Experiment 26*:
SYNTHESIS AND ANALYSIS OF COMMERCIAL POLYMERS

2. Objectives:
To carry out step-wise condensation polymerizations to prepare a polyamide and a set of polyesters.
To compare the solubility of various synthetic and natural polymers in water, acetone, and toluene.
To determine the length of the polyamide polymer formed during the synthesis.

3. Natural vs. Synthetic Organic Polymers
Proteins
hair, skin, tissue
Polysaccharides
cellulose, starch
Polynucleotides
DNA, RNA
Nylons
Polyesters
Acrylics
Polyvinyls
Plastic sheeting and plumbing materials
Polystyrenes
Insulating materials

4. Natural Polymers
RNA

5. Classifications of Synthetic Polymers
Synthetic polymers are classified by their method of synthesis.
Chain-growth
Step-growth
polystyrenes
Polyamides
Polyesters
Synthetic Method
Addition
polymerization
Condensation
polymerization

6. Addition Polymerization
Two molecules combine to form long chain polymer.
Can be linear or branched.
INITIATION: Initiator adds to C=C of styrene, yields reactive intermediate.
PROPAGATION: Reactive intermediate reactions with a second molecule of styrene, yields another reactive intermediate.
TERMINATION: Cycle continues until two reactive intermediates combine to end polymerization.

7. Condensation Polymerization— Polyamides
Two molecules undergo addition accompanied by the loss of a small molecule as a by product.
Each bond forms independently of others.
diamine
Diacid chloride

8. Condensation Polymerization— Linear Polyester
Sodium acetate
diol
anhydride

9. Condensation Polymerization— Cross-Linked Polyester
Sodium acetate
triol
anhydride

10. Properties of Polymers—
Chain Structures
Linear
Cross-linked
Branched
Elastic &
flexible
Rigid & Brittle

11. OVERVIEW
Synthesize polyamide via interfacial polymerization and determine length of fiber formed.
Synthesize linear and cross-linked polyesters.
Compare transparency, elasticity, and hardness of synthesized polymers to other provided synthetic and natural polymers.
Compare solubility of natural and synthetic polymers in various organic solvents.

12. SYNTHESIS—Nylon 6,10
Pour sebacoyl chloride slowly into a solution of hexamethylene diamine.
With tweezers, grab the film which forms at the interface of the two layers and pull up slowly.
Secure the end of the fiber around a large test tube and rotate until no more fiber is produced. KEEP TRACK OF REVOLUTIONS!
Rinse nylon in beaker of tap water, remove from test tube, and set aside for product analysis.

13. SYNTHESIS—Linear and Cross-Linked Polyesters
Cover watch glasses with foil and label.
Place phthalic anhydride and sodium acetate in center of watch glass and mix solids with glass rod.
Add glycerol to one, ethylene glycol to the other.
Heat and mix with glass rod until mixture becomes clear and boils.
Remove from heat and cool to RT.
Remove polymer from foil and set aside for product analysis.

14. ANALYSIS— NYLON FIBER LENGTH
Measure the diameter of the test tube used to collect the nylon fiber.
Determine the length of the fiber produced using the following formula:
Nylon produced (mm) = (Diameter of test tube) * ( p ) * ( # test tube revolutions)
* Where p = 3.14

15. Table 26.1: Nylon Fiber Analysis
Test tube diameter (mm)
# of test tube revolutions
Length of nylon (mm)

16. ANALYSIS— SOLUBILITY TESTING
Label 18 small test tubes 1A-F, 2A-F, and 3A-F.
Measure 3 mL of the appropriate solvent to the test tubes.
Add a small amount of the polymer as indicated in Table 26.2.
Shake to mix the contents completely.
Record the solubility of each polymer in Table 26.2.

17. ANALYSIS— SOLUBILITY TESTING1 A B C D E F
1 = Acetone
A-F = Polymer type 2 A B C D E F
2 = Toluene
A-F = Polymer type 3 A B C D E F
3 = Methanol
A-F = Polymer type

18. Table 26.2: Physical Property and Solubility Results
Polymer Type and Solvent
IMF
(circle all that apply)
Predicted Solubility
Observed Solubility 1 2 3
Acetone
(Sol. or Insol.)
Toluene
Methanol
Synthetic A
Polyamide
LDF DD
HBA
HBD B
Linear polyester C
Cross-linked polyester D
Polystyrene
Natural E
Starch F
Cellulose
Solvent
***In the final lab report, copy/paste this table into your document, and circle the appropriate IMF and solubility predictions by hand. Observed solubility entries can either be typewritten or handwritten.***

19. SAFETY
Sebacoyl chloride, hexamethylenediamine, and sodium hydroxide are CORROSIVE!
Hexane, ethylene glycol, and toluene are TERATOGENIC!
Toluene, acetone, hexane, and methanol are highly FLAMMABLE!

20. WASTE
All liquid waste generated throughout the course of the synthesis and solubility testing can be placed in the “LIQUID WASTE” container.
Solid polymer waste and aluminum foil can be placed in the YELLOW SOLID WASTE CAN at the front of the room.

21. CLEANING
All glassware used during this experiment requires cleaning with SOAP, WATER, BRUSH followed by a final rinse with WASH ACETONE.
DO NOT return any glassware to lab drawer dirty or wet !

22. IN LAB QUESTION (The following question should be answered in the laboratory notebook.)
Differentiate between a chain growth addition reaction and the step growth condensation reactions used to produce the polymers described in this experiment.
Give an example of a polymer produced using each method.

23. IN LAB QUESTION (The following question should be answered in the laboratory notebook.)
List the intermolecular forces present in polystyrene, toluene, and nylon. Explain, in terms of IMF, why polystyrene is soluble in toluene, but nylon 6,10 is not.