材料期刊网

为高值化利用茶产业剩余物,拓宽木塑复合材料中植物纤维来源,以茶粉(TD)为有机增强相,聚丙烯(PP)为基体,采用开炼-注塑工艺制备了TD/PP复合材料；为研究其户外应用及老化机制,采用户外自然老化形式考察了老化时间对TD/PP复合材料力学性能、材色及表面形貌的影响,并用 FTIR分析了其老化机制。结果表明：与木材纤维相比,TD中纤维素含量更少,而各种形式的抽提物含量要高很多,纤维长径比更小。户外自然老化8个月后,TD/PP复合材料的亮度变化值、红绿轴色品指数变化值、黄蓝轴色品指数变化值及色差值分别为37.64、-10.40、-3.38和39.19；TD/PP 复合材料的弯曲、缺口冲击强度、弯曲模量及硬度值分别降低了38.7%、42.4%、41.4%和9.14%。FTIR分析表明,在户外自然老化环境中,TD/PP复合材料中的PP分子链和TD中木质素组分发生了光照降解。SEM照片显示,随户外自然老化时间延长,TD/PP 复合材料表面出现裂纹,且裂纹数量逐渐增多,深度和宽度增大,并且局部地方出现粉化现象。

In order to make high-valued use of the waste tea residue and broaden the plant fiber sources in wood-plastics composites,tea dust/polypropylene(TD/PP)composites were manufactured by open mill and injection molding process with TD as organic reinforcement and PP as matrix.Aiming to explore the outdoor application and weathering mechanism,the outdoor natural weathering form was applied and the effects of weathering time on the mechanical properties,color change and surface morphology of TD/PP composites were investigated.And the weathering mechanism was analyzed by FTIR.The results show that the contents of different extracts from TD is much higher but cellulose content in TD and ratio of fiber length to width is lower compared with wood fibers.The corresponding brightness difference,red green color index difference and yellow blue color index difference are 37.64,-10.40,-3.38 and 39.19,respectively after outdoor natural weathering for 8 months,and the bending strength,notched impact strength,flexural modulus and hardness of TD/PP composites are reduced by 38.7%, 42.4%,41.4% and 9.14%,respectively.The photodegradation of PP matrices chain in TD/PP composites and lig-nin in TD are confirmed by FTIR analysis during the outdoor natural weathering process.And the SEM photograph indicates that there are obviously cracks on the surface of TD/PP composites,the quantity,depth and width of cracks increase,and there even occurs pulverization phenomena in some place.