Phosphorus-containing polymers from THPS. II: Synthesis and property of phosphorus-containing hyperbranched aromatic-aliphatic polyamides

Abstract

Phosphorus-containing hyperbranched aromatic-aliphatic polyamides are prepared via direct polymerization of triacid (B3) with different diamines (A2), which for improving the processability of aromatic polyamides while keeping exellent thermal and mechanical property. The triacid (B3), tris(2-carboxyethyl)phosphine oxide (TCEPO), is synthesized from tetrakis(hydroxymethyl)phosphonium sulfate and its structure is verified by Fourier transform infrared, 1H, 13C and 31P NMR spectroscopy. Then, the polycondensation reaction of TCEPO with p-phenylene diamine, 4,4′-oxyphenylene diamine and 4,4′-methylenedianiline result in three phosphorus-containing hyperbranched aromatic-aliphatic polyamides, and the degree of branching is found between 0.66 and 0.71. Gel permeation chromatography measurement reveal that all hyperbranched aromatic-aliphatic polyamides have moderate number-averaged molecular weights and narrow molecular weight distribution. The Dynamic mechanical thermal analysis results show all polymers have two glass transition temperatures (Tg) in the temperature range 85.3-128.0 °C and have high storage modulus about 1.52-3.19 GPa at 50 °C. The TGA results reveal the initial degradation temperatures (T5) and the temperatures for 10% gravimetric loss (T10) for the hyperbranched aromatic-aliphatic polyamides are in the range of 214-250 and 256-333 °C, and the maximum decomposition temperatures (Tm) are about 500 °C, and also the char yields of polymers at 850 °C are about 39.4-48.4%, which indicate good thermal stability.