硬脂酸/异氰酸酯摩尔比对聚丙烯/木粉复合材料性能的影响

Effects of the Molar Ratios of Stearic Acid/Isocyanate on the Properties of Polypropylene/Wood Flour Composites

用甲苯-2,4-二异氰酸酯(TDI)和硬脂酸(SA)复合改性木粉,在双螺杆挤出机中制备了聚丙烯(PP)基的木塑复合材料(WPC),研究了SA/TDI摩尔比对木粉表面性能、复合材料力学性能和加工性能的影响。结果表明,随着SA/TDI摩尔比的增大,改性木粉的表面张力逐渐减小,与PP的界面张力先减小后增大;与未改性的WPC相比,SA/TDI复合改性剂对WPC的拉伸强度、弯曲强度、缺口冲击强度影响不明显,但对无缺口冲击强度提升较大;当SA/TDI摩尔比为1.07时,复合材料的无缺口冲击强度和熔体质量流动速率分别达到9.74 kJ/m2和13.12 g/10 min,分别比未改性WPC提高了77%和22%。

Wood flour was modified in sequence by toluene-2,4-diisocyanate （TDI） and stearic acid （SA） , and then the modif/ed wood flour were mixed w/th polypropylene（PP） in a twin screw extruder to produce PP/ wood four composites. The influences of the molar ratios of SA and TDI on the surface properties of wood flour, mechanical and processing properties of the composites were studied. The results show that the surface tension of the modified wood flour decreases step by step generally, and the interfacial tension between the wood flour and PP decreases at first and then increases with the raise of molar ratio of SA and TDI. Mechanical tests reveal that, compared with the unmodified composites, SA and TDI have no obvious influence on the tensile, flexural and notched impact strength, but the unnotched impact strength of all modified composites is improved. When the molar ratio of SA and TDI is 1.07, the unnotched impact strength and melt-mass flow rate of composites reach 9. 74 kJ/m2 and 13.12 g/10 min, respectively, improving by 77% and 22% compared with unmodified composites.