Biodegradation in Soil of the PHB/Wood Flour (80/20) and PHB/Sisal Fiber (80/20) Tubes

This paper presents the results of a study that aimed to monitor and evaluate biodegradation in soil, by the mass loss and the mechanical properties of plastic tubes. For this work, there were extruded and injected plastic tubes made of biodegradable polymer poly(hydroxybutyrate) - (PHB) and composite PHB/Wood Flour and PHB/Sisal Fiber, both with 20% fiber. There were used three biodegradation test devices for 30, 60 and 90 days. At the end of each test, the biodegraded samples were taken from soil, washed thoroughly with water, dried and weighed to evaluate the mass loss. Mechanical properties were evaluated using flexural tests before and after biodegradation in soil. Based on the results, it was observed that all the studied tubes lost mass over the biodegradation test, and the tubes of biodegradable composites lost more weight than pure PHB.

本研究针对土壤中塑料管材的生物降解行为开展监测与评估，通过质量损失与力学性能两个维度展开分析。本次实验所用试样包括：以可生物降解聚合物聚羟基丁酸酯（poly(hydroxybutyrate)，PHB）纯料制备的管材，以及分别添加20%木粉、剑麻纤维的PHB基复合材料管材，上述试样均通过挤出与注塑工艺制得。实验采用三套生物降解测试装置，分别开展为期30天、60天与90天的土壤埋置降解实验。每轮测试结束后，取出土壤中的降解试样，经充分水洗、干燥后称重，以评估其质量损失情况；同时分别在土壤降解实验前后对试样进行弯曲测试，以表征其力学性能变化。基于实验结果可知，所有受试管材在降解测试过程中均出现质量损失，且复合材料管材的质量损失幅度高于纯PHB管材。