Thermal Decomposition Mechanism of 2,2-Bis-(4-Hydroxy phenyl)-1,1-Dichloroethylene-Based Polymers

摘要

The work has been conducted as part of the Federal Aviation Administration's(FAA) effort to develop fire-resistant materials for commercial aircraft cabins. Polymers based on 2.2-bis-(40hydroxyphenyl) -1,1-dichloroethylene (bisphenol C, BPC) have thermal and physical properties of bisphenol-A polymers but have an order of magnitude lower heat release in flaming combustion. This is dueto a thermal degradation mechanism that yields only char and noncombustible gases in a fire. Two thermoplastics and one thermoset BPC-based polymer were studied to establish the decomposition mechanism of these materials. Thermal gravimetric analysis, differential scanning calorimetry, infrared spectroscopy, chromatography, and mass spectrometry were used separately and in combination to characterize thethermal degradation mechanism. Results showed that the major volatiles are hydrogen chloride (HCI) and the degradation products of the linking group. The rearrangement through stilbenes and acetylenes is responsiblefor the high char yield when burned.