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Synthesis and characterization of chlorinated bisphenol-based polymers and polycarbodiimides as inherently fire -safe polymers
Two different types of polymers were synthesized and their degradation and combustion behavior were investigated. The first class, 1,1-dichloro-2,2-(4-hydroxyphenyl)ethylidene (bisphenol C) based polymers, were found to be among the most fire-resistant polymers with peak heat release capacities as low as 20 J/g-K. Polymers containing bisphenol C all exhibited exothermic decomposition behavior. When compared to corresponding bisphenol-A-based polymers, these bisphenol-C-containing polymers had higher char yields and lower decomposition temperatures. The presence of bisphenol C in materials, whether as a co-monomer or blends, showed a char enhancement effect; yielding higher char than what is expected by a purely additive affect. Bisphenol C polyarylates and polycarbonates yielded large amounts of HCl and carbon dioxide upon decomposition. Compared with other bisphenol-based polymers, polycarbonates and polyarylates containing bisphenol C yielded significantly less amounts of monomer. Decreasing the concentration of bisphenol C in the copolymers or blends yielded relatively more monomer in the degradation products. The second class of polymers studied were polycarbodiimides, which generally decompose in an endothermic manner to yield quantitative amounts of monomer. The incorporation of TEMPO-containing side chain substituents altered the degradation. TEMPO-based polycarbodiimides decomposed in an exothermic fashion and yielded several other degradation products in addition to the original monomer. These free radical containing polymers showed a 25% reduction in the peak heat release capacity when compared with the control polymer. Neither polymer was found to be fire resistant which is due to their high organic content and essentially 100% weight loss during decomposition.
Stewart, Jennifer Rebecca, "Synthesis and characterization of chlorinated bisphenol-based polymers and polycarbodiimides as inherently fire -safe polymers" (2000). Doctoral Dissertations Available from Proquest. AAI9960792.