核壳结构木塑复合材料抗紫外老化性能试验  

Ultraviolet weathering of HDPE/wood-flour composites with core-shell structure

作　　者：徐兵[1] 梅长彤[1,2] 潘明珠[1,2] 雍宬[1] 王珂[1] 

机构地区：[1]南京林业大学材料科学与工程学院 [2]江苏省林业资源高效利用协同创新中心,南京210037

出　　处：《林业工程学报》2017年第2期33-38,共6页Journal of Forestry Engineering

基　　金：国家"948"项目(2014-4-49);江苏省优势学科二期建设项目(PAPD);江苏省林业资源高效利用协同创新中心项目

摘　　要：以高密度聚乙烯(HDPE)和木粉为主要原料,采用传统木塑复合材料(WPC)制备工艺和共挤出生产工艺,分别制备出均一结构和核壳结构WPC。核壳结构WPC芯层原料配比与均一结构WPC相同(木塑质量比为6∶4),表层则为纯HDPE塑料。将两组材料进行紫外光加速老化试验,并对两组试件的表面颜色、表面形貌、化学基团及抗弯性能分别进行测试和表征。研究结果表明:经2 500 h紫外光照射后,均一结构与核壳结构的WPC表面颜色色差ΔE值分别增加17.59和9.40,核壳结构WPC的抗紫外色变能力明显优于均一结构WPC;电镜照片显示,与核壳结构WPC相比均一结构WPC表面粗糙,在紫外光作用下更容易出现表面裂纹和粉化现象;傅里叶红外光谱分析证明核壳结构WPC表面羟基与羰基基团变化明显低于均一结构WPC,HDPE表层有效延缓了WPC的光氧降解;随着紫外光老化时间延长,两组试件的抗弯性能均呈现下降趋势,经2 500 h老化试验后,核壳结构和均一结构WPC的弯曲强度保留率分别为58.1%和49.7%,弹性模量保留率分别为43.2%和38.0%,表明聚乙烯壳层结构对维持WPC强度有一定的积极作用。Using the high density polyethylene （HDPE） and wood powder as the raw materials together with a small amount of chemical agents, the uniform structure and core-shell structure wood plastic composites （WPCs） were prepared with the traditional extrusion method and co-extrusion method. The core of the core-shell WPC shared the same composition with the uniform structure WPC, in which the ratio of wood powder to plastic was 6：4. The shell material was pure HDPE. Specimens of the type of WPCs were subjected to the accelerated ultraviolet aging test. The surface color, morphology, and chemical composition of specimens were characterized before and after the UV exposure, as well as the mechanical bending strength were examined. The results showed that AE values of the two types of WPCs increased by 17.59 and 9.40 after 2 500 h UV exposure, which indicated that the surface color change of uniform structure WPC was more distinct than that of core-shell WPC. The scanning electron microscope （SEM） revealed that, compared with core-shell WPC, uniform structure WPC was sensitive to the UV aging due to its rough surface. As UV aging processing, the change of the contents of hydroxyl group and carbonyl group in WPC of the core-shell group was less than that in uniform structure WPC, showing that the HDPE shell can delay the photo-oxidation and aging. Mechanical properties were significantly affected by the accelerated ultraviolet aging. After 2 500 h exposure, the retention rate of the bending strength of core-shell structure WPC and uniform structure WPC were 58.1% and 49. 7% respectively, as well as the retention rates of elastic modulus of those two types of WPCs were 43.2% and 38. 0%, respectively.

关 键 词：木塑复合材料 核壳结构 紫外光老化 力学性能 表面颜色 

分 类 号：TB332[一般工业技术—材料科学与工程]