The effect of Tris‐phosphaphenanthrene based phosphonate on the flame retardance, thermal decomposition, and crystallization of bio‐based poly(lactic acid).

With the aim to reduce the flammability of poly(lactic acid) (PLA), herein, Tris‐phosphaphenanthrene based phosphonate (DOT) originated from 10‐hydroxy‐9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO‐OH) and trihydroxymethyl aminomethane (Tris) was incorporated. Interestingly, DOT showed superior flame‐retardant efficiency for PLA, that was, PLA with 1 wt% DOT displayed a LOI value at 29.0%, about 49.0% increment as compared to virgin PLA, and passed a UL‐94V‐0 rating. Apart from the mentioned, cone calorimeter tests clearly demonstrated that DOT was beneficial for reducing the heat release in the whole combustion to some extent, for example, the peak heat release rate and the maximum average values of heat emission with a reduction of 15% and 17%, respectively. It was speculated that the improved flame retardance of PLA containing DOT was related to the melting droplet‐promotion effect and the vapor‐phase activity of DOT. Meanwhile, thermal stabilities of PLA/DOT were well maintained as compared to virgin PLA. Moreover, the existence of DOT promoted the crystallization of PLA owing to the nucleating effect of DOT. [ABSTRACT FROM AUTHOR]