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

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experiment 26

Experiment 26*:

SYNTHESIS AND ANALYSIS OF COMMERCIAL POLYMERS

objectives
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.
slide3

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
slide5

Classifications of

Synthetic Polymers

  • Synthetic polymers are classified by their method of synthesis.

Synthetic Method

Chain-growth

Step-growth

Addition

polymerization

Condensation

polymerization

polystyrenes

Polyamides

Polyesters

slide6

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.
condensation polymerization polyamides
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

slide10

Properties of Polymers—

Chain Structures

Linear

Cross-linked

Branched

Elastic &

flexible

Rigid & Brittle

overview
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.
synthesis nylon 6 10
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.
synthesis linear and cross linked polyesters
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.
analysis nylon fiber length
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

analysis solubility testing
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.
analysis solubility testing1

1

A

1

B

1

C

1

D

1

E

1

F

2

A

2

B

2

C

2

D

2

E

2

F

3

A

3

B

3

C

3

D

3

E

3

F

ANALYSIS—SOLUBILITY TESTING

1 = Acetone

A-F = Polymer type

2 = Toluene

A-F = Polymer type

3 = Methanol

A-F = Polymer type

safety
SAFETY
  • Sebacoyl chloride, hexamethylenediamine, and sodium hydroxide are CORROSIVE!
  • Hexane, ethylene glycol, and toluene are TERATOGENIC!
  • Toluene, acetone, hexane, and methanol are highly FLAMMABLE!
waste
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.
cleaning
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 !
in lab question the following question should be answered in the laboratory notebook
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.
in lab question the following question should be answered in the laboratory notebook1
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.