Abstract:

Traditional waste plastic film recycle method is highly expensive due to the involved washing and drying operations, and the properties of recycled plastic material is poor. Therefore, in this research a method was developed to recycle unwashed waste plastic film by producing sisal fiber enhanced waste polyethylene composites. The waste polyethylene film containing red soil was filled with sisal fiber and then the composite was prepared by extrusion and injection molding process. The effect of red soil and sisal fiber on the property of recovered composite was analyzed. The results showed that the tensile modulus, hardness and heat resistance temperature of the composites containing red soil only were improved by 34.4%, 41.3% and 33.1%, respectively. Owing to poor interfacial bond between red soil and plastic matrix, a slight decrease in tensile strength, flexural properties and impact strength of the composites containing red soil only were observed, indicating that contamination with red soil deteriorates the strength and toughness of the waste plastic based composites, but could improve the modulus and heat resistance temperature of the composites. The presence of sisal fiber obviously improved the strength and toughness of waste plastic film contaminated by red soil. The mechanical properties of the composites increased more obviously with the increase of sisal fiber content. When the content of sisal fiber exceeded a certain value, the porosity was introduced into the composites and the dispersion degree of sisal fiber was reduced, followed by sisal aggregates simultaneously, which led to the decrease of mechanical properties of the composites.

Key words: composites, extrusion, recovery, polymers

摘要：

针对废旧地膜资源化利用过程中出现的高成本和低性能问题，本文提出了废旧地膜免清洗和剑麻纤维边角料增强的废旧地膜资源化利用技术。采用挤出造粒和注塑成型工艺，制备了剑麻边角料填充含红土废旧聚乙烯复合材料，分析了红土和剑麻纤维边角料对废旧地膜的填充作用。结果表明，红土颗粒使废旧地膜注塑试样的拉伸模量、硬度和耐热温度分别提高了34.4%、41.3%、和33.1%。红土颗粒难以和塑料基体形成良好的界面粘结，导致含红土废旧地膜注塑试样的拉伸强度、弯曲性能和冲击强度轻微降低，表明红土颗粒不能对废旧地膜进行增韧增强，但可以提高模量和耐热温度。剑麻纤维边角料对含红土废旧地膜具有明显的增强增韧作用，随着剑麻纤维添加量的增加，剑麻纤维填充的含红土废旧地膜复合材料的力学性能增加。剑麻纤维填充量超过一定值后，会在复合材料中引入气孔，同时会降低剑麻纤维的分散程度，出现剑麻聚集体，导致复合材料的力学性能降低。

关键词: 复合材料, 挤出, 回收, 聚合物