Polyesters & Polyamides

/Polyesters & Polyamides
Polyesters & Polyamides 2016-12-06T05:35:20+00:00

Polyesters & Polyamides

With the preliminary problems associated with the commercialization of neoprene solved, Carothers’ group turned its attention to synthetic fibres, specifically to find a replacement for silk which was in short supply because of trade and political problems between the USA and Japan.

Carothers had postulated some years earlier that if an acid and alcohol could condense with the elimination of water to produce an ester, it should be possible to make a giant molecule (polymer) by linking di-ols to di-acids. This was soon achieved by one of his team, Julian Hill, to give an early polyester but the physical properties were too poor for commercialisation and Carothers turned his attentions to polyamides, replacing the di-ols with di-amines. In 1934 the first successful fibres were made.

Carothers’ team was working with over 100 different materials and he identified them by two numbers, indicating the number of carbon atoms in the di-acid and di-amine. In February 1935 he polymerised adipic acid (C6) and hexamethylene diamine (C6) to give specimen 66 which had good physical properties when it was drawn into a fibre. The material was christened Fiber 66 and, in September 1938 re-christened Nylon66.

Carothers’ immediate superior decided to target just one market with this new product and in May 1940 nylon stockings hit the hosiery stores nationwide. At just over one dollar a pair, five million pairs were sold on the first day. When the US entered the Second World War and arrived in the UK, a few pairs of nylons could buy anything! By that time however, production of nylon had been directed towards the war effort, particularly parachute canopies, rot-proof cords and life rafts and the ladies had to wait a few more years to have an unlimited supply of seamless or fully fashioned nylon stockings.

Today nylon is ubiquitous, being used as threads, sheets or blocks from which a vast range of products can be created.