环氧化改性GTR对聚乳酸结构与性能的影响

Effect of Epoxide-Modified GTR on the Structure and Properties of PLA

以甲酸和过氧化氢对轮胎橡胶粉(GTR)进行改性得到环氧化产物(EGTR),采用熔融共混法制备聚乳酸(PLA)/EGTR共混物,对其微观形貌、结晶行为及力学性能进行系统分析。结果表明:甲酸和过氧化氢成功将GTR分子链上的碳碳双键氧化为环氧基团,EGTR粒子能够均匀分散在PLA基体中,两相间具有良好的相容性。低含量的EGTR能够促进PLA结晶,而高含量的EGTR会抑制PLA的晶体。PLA/5%EGTR共混物具有最高的结晶度(11.1%),是纯PLA的4.8倍。共混物的拉伸强度随EGTR含量的增加而减小,断裂伸长率和冲击强度呈现先增大后减小的趋势。当加入10%EGTR时,共混物具有最大的断裂伸长率和冲击强度,增韧效果和拉伸强度较好,综合力学性能最佳。研究为以GTR作为增韧材料改性PLA提供依据和技术基础,可促进废橡胶的循环回收利用。

After altering ground tire rubber(GTR) with formic acid and hydrogen peroxide,the epoxidation product(EGTR) was produced.The poly(lactic acid)(PLA)/EGTR blends were then made using the melt blending method,and their micro-morphology,crystalline behavior,and mechanical properties were all carefully examined.The results showed that the carbon-carbon double bond on the GTR molecular chain was successfully oxidized to an epoxy group by formic acid and hydrogen peroxide.The EGTR particles were evenly distributed throughout the PLA matrix,demonstrating good compatibility between the two phases.Furthermore,low levels of EGTR promote PLA crystallization,while high levels of EGTR inhibit PLA crystallization.The PLA/5% EGTR blends had the highest crystallinity of 11.1%,which was 4.8 times higher than that of pure PLA.The blends tensile strength declined as the EGTR content increased,while the impact strength and elongation at break showed a tendency of first increasing and then decreasing.When 10% EGTR was added,the blends had the maximum elongation at break and impact strength,with good toughening effect and tensile strength,showing the best overall mechanical properties.The study provides a basis and technical foundation for modifying PLA with GTR as a toughening material and promotes the recycling of waste rubber.