摘要:

Nylons are polymers having amide () linkages. Among this class of polymers, nylon 6 is commercially the most important of the synthetic polyamides available and is used for a variety of purposes, as for example, in the form of fiber in tire cords, apparel, fishing nets, upholstery, hosiery, or in the manufacture of injection and blow-molded objects. There are two common industrial routes to manufacture the polymer from the monomer, ϵ-caprolactam (C1). In the first one, referred to as hydrolytic polymerization, the monomer is mixed with water and is polymerized in the temperature range of 220 to 270°C. The mechanism of polymerization includes three major types of reactions: ring-opening of caprolactam by water, chain growth polymerization, and step growth reaction. Polymers with number-average chain lengths of about 140–180 are usually obtained and these are suitable for use as tire cords, fibers for apparel, as well as resins for molded articles. The second route of polymerization is by the ionic chain growth mechanism, using, for example, initiators like sodium hydroxide, lactamates of alkali metals, and penta-alkyl guanidine. The advantage of this second route lies in that it can be carried out below the melting point (220°C) of nylon and leads to the formation of very high molecular weight polymers. The polymer thus formed is usually employed in making large cast articles. Most nylon 6 is manufactured industrially using the first route, and in view of this, in this review, attention is focused on the design of reactors for nylon 6 through hydrolytic polymerization.

ISSN:1532-1797    

DOI:10.1080/07366578608081973

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The synthesis and evaluation of photoconductive and photosensitive polymers have received considerable attention during recent years because of the increasing demand for such materials in electrophotography and related processes. By now, a wide variety of polymers, unmodified as well as modified chemically or otherwise, has been explored with regard to their potentialities in this field. An authoritative review by Stolka and Pai discussed the basic concepts in photoconductivity, summarizing the experimental techniques commonly employed in this context along with a review of original and patent literature on these systems available through 1976. In a contemporary article, Pen-well, Ganguly, and Smith reviewed the literature on N-vinyl -carbazole polymer systems with specific regard to synthesis, physicochemical property evaluation vis-a-vis their theoretical implications, and related topics. More recently, Biswas and Das reviewed the developments in carbazole-based polymer systems throusrh 1979.

ISSN:1532-1797    

DOI:10.1080/07366578608081974

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:1532-1797    

DOI:10.1080/07366578608081972

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor