Particle Size Related Effects of Multi-Component Flame-Retardant Systems in poly(butadiene terephthalate)

Abstract

Aluminum tris-(diethylphosphinate) (AlPi) is known to have an efficient flame-retardant effect when used in poly(butadiene terephthalates) (PBT). Additionally, better flame-retardant effects can be achieved through the partial substitution of AlPi by boehmite in multi-component systems, which have been shown to be an effective synergist due to cooling effects and residue formation. Although the potential of beneficial effects is generally well known, the influence of particle sizes and behavior in synergistic compositions are still unknown. Within this paper, it is shown that the synergistic effects in flammability measured by limiting oxygen index (LOI) can vary depending on the particle size distribution used in PBT. In conducting thermogravimetric analysis (TGA) measurements, it was observed that smaller boehmite particles result in slightly increased char yields, most probably due to increased reactivity of the metal oxides formed, and they react slightly earlier than larger boehmite particles. This leads to an earlier release of water into the system enhancing the hydrolysis of PBT. Supported by Fourier transformation infrared spectroscopy (FTIR), we propose that the later reactions of the larger boehmite particles decrease the portion of highly flammable tetrahydrofuran in the gas phase within early burning stages. Therefore, the LOI index increased by 4 vol.% when lager boehmite particles were used for the synergistic mixture.

Highly effective flame retarded TPU introduced by a new phosphorus-containing Schiff base derivative at low addition

“…The test results revealed that 20wt% MCA and 10wt% ADP made the LOI value of epoxy resin increase from 19-33%, and UL 94 rating also changed from no rating to V-0 rating. Tomiak F et al [30] applied AlPi and boehmite in poly(butadiene terephthalates)(PBT). As compared to 20wt% ADP, 15wt% ADP and 5wt% boehmite were added to PBT showing better results, whose LOI value further raised from 49-53%, and the residual char also raised from 14wt% to 16wt%.…”