Synthesis of PMM and Synergistic Flame Retardant Effect with Ammonium polyphosphate

Abstract

A novel flame retardant poly {[(2-Methyl-acrylic acid 2-(dimethoxyphosphoryloxy)-ethyl ester]-co-[2-Methyl-acrylic acid 2-(trimethoxysiloxy)-ethyl ester]} (PMM) containing dimethoxyphosphoryloxy and trimethoxysiloxy groups in side chains was synthesized. The structure of PMM was characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (1H NMR), and the thermal performance of PMM was characterized by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The effect of PMM on polypropylene’s flame retardancy and thermal behaviors was investigated by limited oxygen index (LOI), vertical burning test (UL-94), and TG tests. The experimental results indicate that the addition of PMM helps to improve the flame retardancy and thermal stability of PP. When the addition of PMM and APP in PC was 15% and 20%, the LOI value of PC reached 28.4%, and the UL-94 test rating reached V-0 level. The charred structure observed by scanning electron microscopy (SEM) indicated that the char surface for PP/APP/PMM system holds an intumescent char structure compared to neat PP, and the synergy exists in the composites. The PMM slightly decreased the tensile property in terms of strength but increased the elongation at break for PP composites.