Modification of Nylon

I. Introduction 433

II. Synthesis of Nylons 435

III. Background for Nylon Modification 438

IV. Modification of Nylon Resins 444

V. Modification of Nylon Fibers 462

VI. Summary 472

Exercises 473

References 473

I. INTRODUCTION

Nylon is a generic name of synthetic polyamides in which amide groups recur as integral parts of the main polymer chains. Nylon-6,6 (polyhexamethylene adipamide) is the nylon first ever prepared. In 1935, W. H. Carothers succeeded in obtaining it by condensation of hexanediamine and adipic acid. He further claimed that other nylons such as nylon-11 (poly-coaminoundecanoic acid) and nylon-6,10 (hexamethylene 1,10-decadiamide) could be also prepared. Du Pont built a pilot plant and produced a nylon-6,6 yam, which was introduced to the market of brush bristles and ladies' stockings. P. Schlack succeeded in preparing another nylon. He found that heating εcaprolactam with water yielded nylon-6 (polycaprolactam) to high molecular weight. The large-scale production of nylon-6 was started by I. G. Farbenindustrie, which was largely used as bristles and filaments. P. Lafont at Rhone-Poulenc prepared nylon 12 (poly-co-dodecanolactam).