β-环糊精对长支链化聚乳酸复合材料发泡质量及力学性能的影响

Effect ofβ-Cyclodextrin on Foaming Quality and Mechanical Properties of Long-branched Polylactic Acid Composite

以苯乙烯-丙烯酸缩水甘油酯共聚物(ADR)为扩链剂对聚乳酸(PLA)进行长支链化,利用液相凝胶色谱测试仪(GPC)、示差扫描量热分析(DSC)等研究了ADR用量对PLA综合性能的影响,同时探讨了β-环糊精(BC)对长支链化PLA发泡复合材料发泡质量及力学性能的影响。结果表明:添加0.5%(质量分数,下同)的ADR使改性PLA的重均分子质量从2.2×105 g/mol增加到2.61×105 g/mol,改性后PLA的相对分子质量分布最高达到4.23,熔体黏度也明显提高。当在长支链化PLA中添加BC进行发泡时,发现添加5%的BC能得到理想的改性PLA复合材料泡孔结构,其泡孔平均直径达到28.8μm;当BC含量为3%时,与纯PLA发泡材料相比,发泡长支链化PLA/BC复合材料的弯曲、拉伸和冲击强度分别增加了9.1%、14.3%、52.3%。

The effect of the dosage of ADR on the comprehensive performance of PLA was studied by using styrene-glycidyl acrylate copolymer(ADR)as chain extender,and the effect ofβ-cyclodextrin(BC)on the foaming quality and mechanical properties of PLA foaming composite was also discussed by gelpermeation chromatography(GPC)and differential calorimeter(DSC)and other methods.The results showed that adding 0.5%(mass fraction,the same below)of ADR making the molecular weight of the modified PLA increased from 2.2×105 g/mol to 2.61×105 g/mol,relative molecular mass distribution of the modified PLA increased to 4.23,the melt viscosity was improved obviously.When BC was added into the long branched PLA for foaming,it was found that 5%BC could obtain the ideal modified PLA composite cell structure,with the average diameter of the cell reaching 28.8μm.When the BC content reached 3%,the bending,stretching and impact strength of the foaming long-branched PLA/BC composite increased by 9.1%,14.3%and 52.3%,respectively,compared with the pure PLA foaming composite.