Effects of treated waste silicon rubber on properties of polylactic acid/ammonium polyphosphate composites

Considering the massive waste silicone rubber composites (WSiRC) in electrical and electronic engineering industries every year, the utilization of WSiRC is a meaningful and urgent task. In this study, WSiRC was utilized after a simple treatment in the flame retardant polylactic acid (PLA). The TG data in N2 indicated that the char residues at 700 °C of the PLA/ammonium polyphosphate(APP)/WSiRC samples are improved with the loading of WSiRC, which means that WSiRC could act as the carbonization promoter for the PLA blends. Moreover, it is found in LOI, UL94, and cone tests that WSiRC can only improve the flame retardancy of PLA in an appropriate loading range since the crosslink structure formed by WSiRC may interact with that formed by APP and jointly improve the char-formation ability of PLA. However, too much WSiRC deteriorated the flame retardancy of PLA because of the effect of WSiRC cluster at its higher loading. The photographs of the char residue after the cone tests also manifested that. The cone data showed that WSiRC could suppress the production of smoke as well. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45231.