TABLE OF CONTENTS Polyamides are a very attractive class of construction polymers and have been used for numerous engineering applications because of their excellent tensile properties, chemical and abrasion resistance, and high melting point and fatigue resistance {877977} {660978}. The degradation of polyamides is a complex process {881010} {795751} {787552} and can lead to many different products according to a recent review {743554}. The principal degradation product from PA-6 pyrolysis is generally agreed to be the cyclic monomer (Scheme 11), caprolactam, but the question of which additional products are detected seems to depend upon the sample size and the experimental conditions used {886353} {758424}.
However, recent research agrees that the main route of thermal degradation of PA-6 is the formation of caprolactam with yields as high as 85% the presence of oligomeric products with nitrile and vinyl chain ends, which are formed as a result of depolymerisation, has been confirmed {890179} [a.17, a.114]. The increase of reaction order of the overall decomposition of PA-6 above 420 C is correlated with the formation of by-products. Especially, the formation of the cyclic dimer seems to be a second-order reaction, which is responsible for the increase of the overall reaction order. The observed first-order reaction of ?-caprolactam formation (Table...
