28 Flammability of Phosphorus-Containing Aromatic Polyesters: A Comparison of Additives and Comonomer Downloaded via UNIV OF CALIFORNIA BERKELEY on July 25, 2018 at 18:47:07 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.
Flame Retardants R O B E R T W. S T A C K M A N Celanese Research Company, Summit, N J 07901
The use of phosphorus compounds as flame retardants has been reviewed by Lyons and others (1, 2^ _3, 5). The mechanism of the action of this element is generally accepted to involve decomposition to produce acids which function as char promoters. Phosphorus compounds are particularly effective flame retardants for polyesters where they function to increase the char yields. While there are a large number of both phosphorus additive and comonomer compounds available, no direct comparisons have been reported between the effectiveness of the two methods of incorporation, aside from some references to the lack of permanency of many additive compositions. The use of additives, on the other hand, may provide a greater flexibility, allowing the production of polymeric compositions of varying degrees of flame retardance, from the same base resin. The purpose of this study was to determine whether any real differences in effectiveness are detectable due to the method of incorporation of phosphorus into a polymer system. Aromatic polyphosphonates have been found to be especially effective flame retardant additives for polyester compositions (6, _7, £0, especially for polyethylene terephthalate. These additives are phosphorus esters of a di- phenol with the following structure: 0
0-8412-0540-X/80/47-121-425$05.00/0 © 1980 American Chemical Society Carraher and Tsuda; Modification of Polymers ACS Symposium Series; American Chemical Society: Washington, DC, 1980.
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MODIFICATION OF POLYMERS CH
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