Some unsolved problems In the science of nylon and polyester fibres

Despite the commercial importance of melt-spun fibres there are many aspects of their science that are not well understood. A common working model of fine structure is a pseudo-fibrillar assembly of crystallites linked by tie molecules in amorphous regions, but other possibilities are suggested . Heat-setting is an accepted industrial practice, but the science is poorly understood: there is a lack of good experimental data and no adequate theory. Even the nature of the basic mechanisms is not certain. There has been little attempt to analyze the mechanics of the material. Composite models a re inadequate, but network models show more promise. There are a number of differences between nylon and polyester fibres, which are unexplained. It will be necessary to solve these problems to maximize the industrial potential of nylon and polyester fibres .