Phosphotungstic acid is a typical kind of superior catalysts, and it is hardly to intercalate into the layered double hydroxides (LDH) by ion-exchange process because of its low negative charge. In this work, a phosphotungstic acid intercalated MgAl-LDH (PWA-LDH) was prepared by reconstruction method, and it was then introduced into poly (lactic acid) (PLA) resin in association with intumescent flame retardant (IFR) by melt blending to prepare a flame-retardant biodegradable PLA composite. The effects of PWA-LDH on the flame retardancy of PLA composites were characterized by limiting oxygen index (LOI), vertical burning test (UL-94) and cone calorimeter test. The results showed that the composite sample containing 18.0 wt% IFR and 2.0 wt% PWA-LDH achieved the maximal LOI value of 48.3%, passed the UL-94 V-0 rating, and significantly decreased the peak heat release rate from 306.3 kW/m² of neat PLA to 40.1 kW/m². Thermogravimetric analysis showed that both the thermal stability and the char formation were enhanced. The char morphology observation revealed that PWA-LDH was beneficial to form dense and compact char layers. It was demonstrated that there existed a synergistic effect between IFR and PWA-LDH in promoting the char formation and enhancing the fire resistance.

磷钨酸是一种典型的高级催化剂，由于其负电荷低，因此很难通过离子交换过程插入层状双氢氧化物（LDH）中。在这项工作中，通过重构方法制备了嵌入磷钨酸的MgAl-LDH（PWA-LDH），然后通过熔融共混将其与膨胀型阻燃剂（IFR）一起引入聚（乳酸）（PLA）树脂中。制备一种可生物降解的阻燃PLA复合材料。通过极限氧指数（LOI），垂直燃烧试验（UL-94）和锥形量热仪试验表征了PWA-LDH对PLA复合材料阻燃性的影响。结果表明，包含18.0 wt％IFR和2.0 wt％PWA-LDH的复合材料样品的最大LOI值达到48.3％，通过了UL-94 V-0评级，纯PLA的²到40.1 kW / m ²。热重分析表明，热稳定性和焦炭形成均得到增强。炭的形态观察表明，PWA-LDH有利于形成致密的致密炭层。结果表明，IFR和PWA-LDH在促进炭形成和增强耐火性方面具有协同作用。