Step Growth Polymer

1. Introduction

The technology enhancement of any population is connected to the materials available. Therefore scientists have developed new materials to cope with the development of human civilisation. With the use of organic chemistry, new material is producing commonly synthetic polymers. Due to the versatility of these polymers it allows creation and fabrication of materials that cannot be attain from materials such as wood, metals and ceramics. The raw materials of polymer derived from petroleum and with the advance technology the synthesis of raw material became cheap and useful.

2. Step Growth or Condensation Polymerizations

Step Growth polymerization is a polymerization process in which chain growth occurs in stepwise manner. It is formed by reaction of difunctional molecules, with each new bond created in separate steps. Monomers will react with other monomers to form dimmers, dimmers than react with dimer to form tetramers, tetratmer react with monomers to form pentamers and so on. The stepwise manner plays an important role for both their molecular weights and molecular weight distribution. At the end high molecular weight polymer molecules is produce. The step growth process can be done in two ways; (1) reaction between A-A monomers will react with B-B monomers to give (A-A-B-B) polymer and (2) the self condensation A-B monomer to give (A-B)n polymers. New covalent bond is formed at the end of polymerization by polar reaction such as nuclephilic acyl substituition.

3.1. Polyamides

Wallace M. Carothers and his associates E.I. Dupont de Numours & Company in the 1930s begin their fundamental research into the reaction of aliphatic dicarboxylic acids and diols. From adipic acid and ethylene; a high molecular weight polymer is obtained that could be drawn into fibres which are polyesters.

The polyesters fibres had melt transitions (Tm) too low for use as textile fibres. Then he concentrates to reactions of dicarboxylic acids and...