A novel polyurethane containing phosphorus and nitrogen (PU) was synthesized and characterized with ¹H-NMR, FTIR, and GPC. It was served as flame retardant to blend with poly(L-lactide) (PLLA) through solution casting technique. PU particle dispersed in PLLA substrate irregularly and improved the crystallinity of PLLA. The initial decomposition temperature of PLLA composite was significantly lower, but char residue increased. Flame retardancy and mechanical properties of PU/PLLA blends were evaluated. When the blend ratio of PU/PLLA was 10 wt%, LOI was 26.8%, and UL94 test reached V-2 grade. The inflaming retarding mechanism was outlined. The tensile strength of PLLA blend was 42.8 MPa, while its elongation at break was only 2%. By adjusting PU and adding compatilizer, the balance between flame retardancy and good mechanical properties of PLLA would be controlled.

中文翻译：

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用磷和氮合成聚氨酯阻燃聚（L-丙交酯）

合成了一种新型的含磷和氮的聚氨酯 (PU) 并表征为¹H-NMR、FTIR 和 GPC。通过溶液浇铸技术与聚（L-丙交酯）（PLLA）共混用作阻燃剂。PU颗粒不规则地分散在PLLA基材中，提高了PLLA的结晶度。PLLA 复合材料的初始分解温度显着降低，但残炭量增加。评估了 PU/PLLA 共混物的阻燃性和机械性能。当PU/PLLA的混合比为10wt%时，LOI为26.8%，UL94测试达到V-2级。概述了阻燃机制。PLLA 共混物的拉伸强度为 42.8 MPa，而其断裂伸长率仅为 2%。通过调整PU和添加相容剂，可以控制PLLA的阻燃性和良好的机械性能之间的平衡。