可降解聚乳酸沙障降解性能研究

按不同坡向和不同坡位,对乌兰布和沙漠铺设3.5a的聚乳酸(PLA)方格沙障的降解性能进行了研究。通过单根纱线拉伸试验研究了沙障的力学性能变化,利用天平称重测定了失重率变化,并利用环境扫描电镜观察了障体表面形态变化。结果表明,与未使用的PLA沙障相比,随坡位的上升,障体4个部位的单纱断裂强度呈现出不同程度的降低,各部位的单纱断裂强度由小到大排序依次为:迎风面、顶部、背风面、贴地面。从坡底到坡顶,障体的失重率整体呈现出逐渐增大的变化特点。沙障暴露部分的降解现象较贴地部分的明显。风沙流吹蚀磨蚀是影响PLA沙障材料性能的最主要因素,光照的影响其次,沙区土壤微生物的作用最小。

Degradation Characteristics of Degradable Polylactic Acid Sand Barrier

In order to understand the degradation characteristics of polylactic acid(PLA) square sand barriers,the PLA square sand barriers paved for 3.5 years were investigated in different slope directions and at different slope positions in the U Lan Buh Desert.Changes in the mechanical properties of the PLA sand barriers were studied by means of yarn tensile test.Changes in loss ratio were weighed by electronic balance and changes in surface morphology of sand barriers were described by environmental scanning electron microscope(ESEM).Results are as follows: Compared with the original PLA sand barriers,yarn breaking tenacities of four positions of the PLA sand barrier decreased differently with slope position ascending,and the order from low to high was windward side,top side,leeward side and ground side.Loss ratios gradually increased from the bottom to the top of the slope.The degradation of exposed section of the sand barrier was more serious than that of ground section.Blastation and abrasion by wind flow is the most important factor to the degradation of the PLA sand barrier,ultraviolet irradiation is in the second place,and microorganism in sandy soil has the minimal impact.