A new method has been presented to simultaneously enhance both the flame retardancy and toughness of polylactide acid composites by introducing castor oil-based polyurethane and ammonium polyphosphate via reactive blending. The in situ polymerization of castor oil and toluene diisocyanate in the polylactide acid matrix has been confirmed by the Fourier transform infrared spectroscopy. The flame retardant test results indicate that the introduction of 20% ammonium polyphosphate can increase the limiting oxygen index of polylactide acid composites from 19.3% to 27.2%, upgrade the UL-94 rating from no rating to V-0, and decrease the peak heat release rate from 505.5 to 337.0 kW/m2. Moreover, the toughness of polylactide acid is also improved significantly, with the elongation at break and notched impact strength increasing to 37.0% and 7.59 kJ/m2, respectively. The possible mechanisms for both flame retardancy and toughness are also discussed and proposed.

中文翻译：

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与蓖麻油基聚氨酯和聚磷酸铵反应共混同时提高聚乳酸的防火性能和韧性

提出了一种新方法，通过反应共混引入蓖麻油基聚氨酯和聚磷酸铵，同时提高聚乳酸复合材料的阻燃性和韧性。蓖麻油和甲苯二异氰酸酯在聚丙交酯酸基质中的原位聚合已通过傅里叶变换红外光谱证实。阻燃测试结果表明，20%聚磷酸铵的引入可使聚乳酸复合材料的极限氧指数由19.3%提高到27.2%，UL-94等级由无等级提升至V-0，峰值热降低释放率从 505.5 到 337.0 kW/m2。此外，聚乳酸的韧性也显着提高，断裂伸长率和缺口冲击强度提高到37.0%和7.59 kJ/m2，分别。还讨论并提出了阻燃性和韧性的可能机制。