三聚氰胺聚磷酸盐对竹纤维/聚丙烯复合材料力学及阻燃性能的影响

采用三聚氰胺聚磷酸盐（MPP）作为阻燃剂，加入到竹纤维/聚丙烯（BF/PP）复合毡中，制备MPP-BF/PP复合材料。采用力学测试和SEM研究MPP对MPP-BF/PP复合材料力学性能和微观形貌的影响；采用极限氧指数（LOI）、热失重（TG）和吸水率为指标研究MPP对MPP-BF/PP复合材料阻燃性、热稳定性和耐水性的影响。测试表明:MPP的质量分数小于30wt%时，MPP-BF/PP复合材料弯曲强度和冲击强度随MPP质量分数的增加先增大后减小，当MPP质量分数达到5wt%时，MPP-BF/PP复合材料呈现出最佳的弯曲强度和冲击强度；MPP在MPP-BF/PP复合材料内部均匀分布，而随着MPP质量分数的增加，MPP-BF/PP复合材料断裂面的粗糙度明显提高，即MPP与PP界面相容性变差，使其力学性能降低。LOI测试结果表明，MPP可以有效提高MPP-BF/PP复合材料的阻燃性能，当MPP质量分数为30wt%时，MPP-BF/PP复合材料LOI达到24.3%。热失重测试表明，MPP的加入可提高MPP-BF/PP复合材料的热分解温度，促进其残炭率明显增大，有利于提高MPP-BF/PP复合材料阻燃性能。耐水性能测试结果表明，MPP质量分数小于20wt%时，MPP对MPP-BF/PP复合材料的耐水性能没有明显影响。采用模糊综合评价法分析表明，MPP质量分数为10wt%时，MPP-BF/PP复合材料性能最优。 

Effects of melamine pyrophosphate on mechanical and flame retardant properties of bamboo fiber/polypropylene composites

The melamine pyrophosphate (MPP) was introduced into bamboo fiber/polypropylene (BF/PP) mats as flame retardant to prepare a series of MPP-BF/PP composites. The effects of MPP mass fractions on mechanical properties, microstructures of MPP-BF/PP composites were investigated by mechanical test and SEM. The flame retardancy, thermal stability and water resistance of MPP-BF/PP composites were studied using limiting oxygen index (LOI), thermal gavimetric (TG) and water absorption as index. The results show that the bending strength and impact strength of the MPP-BF/PP composites increase firstly and then show a decreased trend when the mass fraction of MPP is less than 30wt%. As the mass fraction of MPP increases up to 5wt%, the bending strength and impact strength of MPP-BF/PP composites reach the optimal values. MPP distributes evenly in the MPP-BF/PP composites, but the surface roughness of cross section increases with the mass fraction of MPP increasing, which means the interface compatibility between MPP and PP becomes worse, reducing the mechanical properties of MPP-BF/PP composites. The results of LOI indicate that the flame retardancy of MPP-BF/PP composites is enhanced with the mass fraction of MPP increasing. When the mass fraction of MPP reaches to 30wt%, the LOI is 24.3%. TG test reveals that the addition of MPP enhances the thermal decomposition temperature and char residues of MPP-BF/PP composites, contributing to the flame retardancy. The test of water resistance of MPP-BF/PP composites indicates that the water absorption and thickness swelling values are almost not affected by the mass fraction of MPP when less than 20wt%. According to fuzzy comprehensive evaluation, the MPP-BF/PP composites will achieve the optimal properties when the mass fraction of MPP is 10wt%.