Which one is classified as a condensation polymer?

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Engineering

Chemistry

Polymers

Classification of organic compounds

Basic concepts of organic chemistry

Question

Which one is classified as a condensation polymer?

A

Neoprene

B

Dacron

C

Acrylonitrile

D

Teflon

Condensation polymers form when monomers join together, releasing small molecules like water as byproducts. They typically involve two different functional groups (e.g., -OH and -COOH).

Dacron (polyester) is made from ethylene glycol and terephthalic acid, with the reaction:

$HO - R - OH + HOOC - R' - COOH \to [- O - R - O - C (=O) - R' - C (=O) -] n + H_{2} O$

Neoprene, Acrylonitrile, and Teflon are addition polymers, formed without byproduct loss.

Final Answer: Dacron

A condensation polymer is formed by the step-growth polymerization mechanism where monomers join together with the elimination of small molecules like water, methanol, or HCl. This is in contrast to addition polymers, which form without the loss of any small molecules and typically involve monomers with carbon-carbon double bonds.

Let's evaluate the options:

Neoprene: This is a synthetic rubber made from chloroprene (2-chloro-1,3-butadiene) via addition polymerization. No small molecule is eliminated.

Dacron: This is a trade name for polyester, specifically polyethylene terephthalate (PET). It is formed from ethylene glycol and terephthalic acid (or dimethyl terephthalate) with the elimination of water (or methanol), making it a classic example of a condensation polymer. The reaction can be represented as:

n HO - CH {CH}_{2} - OH + n HOOC - C H_{6} - COOH \to [- O - CH {CH}_{2} - O - CO - C H_{6} - CO -] n + 2 n H_{2} O

Acrylonitrile: This is a monomer (CH₂=CH-CN) used to form addition polymers like polyacrylonitrile (PAN), which is a component of synthetic fibers such as Orlon. No small molecule is lost.

Teflon: This is the trade name for polytetrafluoroethylene (PTFE), formed by the addition polymerization of tetrafluoroethylene (CF₂=CF₂). No small molecule is eliminated.

Therefore, Dacron is the correct answer as it is a condensation polymer.

Related Topics and Formulae

Condensation Polymerization: A polymerization reaction that involves the combination of monomers with the elimination of small molecules. Common examples include polyamides (nylon) and polyesters.

Addition Polymerization: A reaction where unsaturated monomers add together without the loss of any small molecules. Examples include polyethylene, polypropylene, and PVC.

Key Formula for Condensation: The general process for a polyester is:
$n HO - R - OH + n HOOC - R' - COOH \to [- O - R - O - CO - R' - CO -] n + 2 n H_{2} O$