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

Abstract

<div><p>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 <i>p</i>-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 (<i>T</i>_<i>g</i>) 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 (<i>T</i>₅) and the temperatures for 10% gravimetric loss (<i>T</i>₁₀) for the hyperbranched aromatic-aliphatic polyamides are in the range of 214–250 and 256–333 °C, and the maximum decomposition temperatures (<i>T</i>_<i>m</i>) 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.</p></div