Polymers with improved flammability characteristics. I. Phenolphthalein‐related homopolymers

Publisher Website
Google Scholar
Abstract
Improved fire resistance occurs for phenolphthalein‐related polycarbonates and polyesters compared to bisphenol‐A polymers and emphasizes the importance of polymer composition and polymer structure in affecting the flammability of a polymer. Phenolphthalein‐related polymers are able to produce a higher degree of crosslinking during pyrolysis which subsequently leads to higher char yields. The correlations between oxygen index and char yield for various polymers are obtained and discussed. Polycarbonates and polyamides usually show higher oxygen indices than the corresponding polyesters of related structures. This indicates that the nature of the pyrolysis products has a measurable effect on the flammability of a specific polymer. Among many factors, polycarbonates should release more CO2 from the breakdown of the carbonate group, and polyamides should produce relatively nonflammable nitrogen‐containing products during pyrolysis, thus accounting in part for these results.