纳米TiO2对木纤维/聚丙烯复合材料抗紫外老化性能的影响

Effect of nano TiO2 on UV aging resistance of wood fiber/polypropylene composites

木塑复合材料作为室外建筑装饰材料时,暴露在紫外光的照射下,易老化导致其力学性能降低、使用寿命减少。将具有高效紫外线屏蔽能力的金红石型纳米TiO2经硅烷偶联剂KH-570表面改性后,与木纤维(WF)、聚丙烯(PP)等制备了TiO2-WF/PP复合材料。对TiO2-WF/PP复合材料进行了人工加速紫外老化,并利用FTIR、TG、SEM、力学性能分析、颜色变化分析等手段,探究了纳米TiO2对WF/PP复合材料抗紫外老化的影响。结果表明:改性纳米TiO2粒子在WF/PP复合材料中均匀分散,无明显团聚,且其加入显著提高了复合材料的热稳定性;TiO2-WF/PP复合材料随着老化时间的延长,力学性能下降相对较小且颜色变化较小。当纳米TiO2的质量分数为2 wt%~3 wt%,老化2 000 h时后,TiO2-WF/PP复合材料的拉伸强度、冲击强度仅分别下降10.0%和12.6%;未加入纳米TiO2颗粒的WF/PP复合材料,则分别下降20.2%和22.6%。

When wood-plastic composites are used as outdoor building decoration materials,they are exposed to ultraviolet light,resulting in mechanical properties and service life reducing.The rutile nano TiO2 with high-efficiency ultraviolet shielding ability was surface-modified with a silane coupling agent KH-570,and then TiO2-WF/PP composites were prepared with wood fiber(WF),polypropylene(PP).The artificial accelerated UV aging of the composites was carried out.The effects of nano TiO2 on the UV aging of WF/PP composites were investigated by means of FTIR,TG,SEM,mechanical properties analysis and color change analysis.The results show that the modified nano TiO2 particles can be uniformly dispersed in WF/PP composites without obvious agglomeration,and their addition significantly improves the thermal stability of the composites;with the aging time prolonged,the decrease of the mechanical properties of WF/PP composites is relatively small and the color change scope is small.When the mass fraction of nano TiO2 particles is 2 wt%-3 wt%and aging for 2000 h,the tensile strength and impact strength of the TiO2-WF/PP composites only decrease by 10.0%and 12.6%,respectively,while those without the addition of nano TiO2 particles decrease by 20.2%and 22.6%,respectively.