A novel biodegradable phosphorus-containing copolyester with preferable flame retardancy and mechanical properties
Abstract
Phosphorus-containing poly(butylene succinate-co-3-hydroxyphenylphosphinyl-propionate) (PBSH) was synthesized through esterification and melt copolycondensation of succinic acid (SA), 1,4 butanediol (BD) and 3-hydroxyphenylphosphinyl-propionic acid (HPPPA). The chemical structure of PBSH was confirmed using Fourier transform infrared spectroscopy (FTIR) and 1H NMR spectroscopy. It is found that the addition of HPPPA can improve the initial decomposition temperatures of copolyesters. The LOI values of the PBSHs were increased from 22.0% to 35.0% and the UL-94 ratings of vertical burning were improved to V-0 with a relatively low content of phosphorus containing comonomer. Furthermore, we used melt postpolycondensation to increase the molecular weights of the copolyester and found that a copolymer with enough high molecular weight can maintain its good mechanical properties for practical applications.