反应性挤出法合成PLA/LDHs纳米复合材料的性能及聚合反应动力学

Synthesis, Performance and Polymerization Reaction Kinetics of PLA/LDHs Nanocomposites by Reactive Extrusion Process

以L-丙交酯和水滑石（LDHs）为原料、辛酸亚锡（Sn（Oct）2）为催化剂,采用反应性挤出法合成了聚乳酸（PLA）/LDHs纳米复合材料,并通过正交试验优化得到最佳工艺条件。结果表明,最佳反应挤出工艺条件为LDHs用量0.4%,Sn（Oct）2用量2%,螺杆转速20 r/min,反应温度170℃。通过凝胶渗透色谱（GPC）、傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）等手段对所制PLA/LDHs纳米复合材料进行了分析,结果表明,通过反应性挤出法合成的PLA/LDHs纳米复合材料分子量为38 289 g/mol,且具有α-晶型结构。此外,PLA/LDHs纳米复合材料力学性能测试结果表明,复合材料的力学性能得到显著提升;热重（TG）和差示扫描量热分析（DSC）结果表明,PLA/LDHs纳米复合材料的热稳定性和结晶性能均得到明显改善。反应动力学研究结果显示,PLA0和PLA/LDHs纳米复合材料的表观反应速率常数分别为7.639×10^3和8.496×10^3 g/（mol·min）,表明LDHs可以提高PLA的聚合反应速率。

Poly（lactic acid）/layered double hydroxides（PLA/LDHs）nanocomposites were synthesized by reactive extrusion process using Sn（Oct）2,L-lactide and LDHs,in which the Sn（Oct）2 was served as catalyst.The orthogonal experiment results showed that the optimum conditions were as follows：the dosage of LDHs was 0.4%,the content of Sn（Oct）2 was 2%,the screw speed was 20r/min and the reaction temperature was 170℃.Then,the prepared PLA/LDHs nanocomposites were analyzed by GPC,FTIR,XRD and so on.These test results showed that the PLA/LDHs nanocomposites,which synthesized by reactive extrusion,had a molecular weight of 38 289 g/mol and containedα-crystalline structure.In addition,the mechanical properties test of PLA/LDHs nanocomposites showed that the mechanical properties of the composites had been significantly improved.The results of TG and DSC demonstrated that the thermal stability and crystallinity of PLA/LDHs nanocomposites had also been significantly improved.The polymerization reaction kinetics showed that the apparent rate constant of PLA0 and PLA/LDHs nanocomposites were 7.639×10^3 and 8.496×10^3 g/（mol·min）respectively,which demonstrated that LDHs enhanced the reaction rate of PLA.