Work

Improving Flame‐Retardant Properties of Poly (Lactic Acid) Composites Using Maleic Anhydride‐Modified DOPO and SiO2

Year: 2025

Type: article

Abstract: ABSTRACT Polylactic acid (PLA) is well regarded for its excellent environmental friendliness; however, its flammability presents a significant barrier to wider applications. Developing highly flame‐retardant PLA (with a limiting oxygen index, LOI, greater than 30%) using simple, general methods remains a challenge. In this study, maleic anhydride (MA) was used to modify 9,10‐dihydro‐9‐oxa‐10‐oxide (DOPO), enhancing its thermal stability and interaction with the PLA matrix. Additionally, by leveraging the carbonization effect of nano‐SiO2, DOPO‐MA was compounded with nanosilica to further improve PLA's flame‐retardant properties. As a result, a highly flame‐retardant PLA with an LOI of 31.3% and a UL‐94 V‐0 rating was successfully prepared using 5 wt.% DOPO‐MA and 3 wt.% SiO2. Furthermore, total heat release (THR) and peak heat release rates (pHRR) of PLA decreased by 7% and 25%, respectively. Detailed analysis of the flame‐retardant mechanism revealed that nano‐SiO2 significantly increased the residual char content and promoted the formation of a more stable graphite carbon structure. Moreover, silica effectively suppressed the generation of combustible gases in the pyrolysis products of PLA, collectively enhancing its flame‐retardant properties. This study presents a straightforward and scalable approach for designing highly efficient phosphorus/silica‐containing synergistic flame retardants, offering valuable insights into PLA flame retardancy.

Source: Journal of Applied Polymer Science

DOI: 10.1002/app.57139