From 09/23/2014 through 5/16/2012
Fiber Reinforced Polyamides
Polyamide (Nylon) Fibers
1. “A polyamide is a polymer containing monomers of amides joined by peptide bonds. They can occur both naturally and artificially, examples being proteins, such as wool and silk, and can be made artificially through step-growth polymerization or solid-phase synthesis, examples being nylons, aramids, and sodium poly(aspartate). Polyamides are commonly used in textiles, automotives, carpet and sportswear due to their extreme durability and strength.
The amide link is produced from the condensation reaction of an amino group and a carboxylic acid or acid chloride group. A small molecule, usually water, or hydrogen chloride, is eliminated.
The amino group and the carboxylic acid group can be on the same monomer, or the polymer can be constituted of two different bifunctional monomers, one with two amino groups, the other with two carboxylic acid or acid chloride groups.
Amino acids can be taken as examples of single monomer (if the difference between R groups is ignored) reacting with identical molecules to form a polyamide.”
(Wikipedia, Polyamides, 5/16/2012)
2. Forming aramid copolymers is difficult because of the very different reactivity ratios of the reactants. Lee of Dupont, developed a method for forming a controlled copolymer composition by mixing two organic (N-methyl-2-pyrrolidone (NMP) or dimethylacetamide) solutions. One of the solutions contains a precise ratio of amino phenyl benzimidazole and paraphenylene diamine dihydrochloride. The other solution with the same solvent contains terephthaloyl dichloride . Polymerization occurs when the two solutions are mixed. The HCl form forms a rigid monomer enabling precise copolymerization to high molecular weights.
Process of forming an aramid copolymer
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Roger D. Corneliussen
Maro Polymer Links
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Copyright 2012 by Roger D. Corneliussen.
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* Date of latest addition; date of first entry is 5/16/2012.