ILs-MPEG对PLA玻璃化转变温度和热稳定性的影响

利用链长不同的含聚乙二醇单甲醚侧链的咪唑基离子液体( ILs-MPEG)改性聚乳酸(PLA),通过熔融共混法制备PLA/ILs-MPEG共混物试样.采用扫描电子显微镜观察了ILs-MPEG在PLA基体中的分散情况,应用差示扫描量热仪和热重分析仪,分别研究了ILs-MPEG对PLA的增塑作用与热稳定性的影响.结果表明,ILs-MPEG可较为均匀地分散在PLA基体中,但随着其侧链长度增加,分散性下降.ILs-MPEG能促使PLA的玻璃化转变温度(Tg)明显降低,表现出显著的增塑作用,同时PLA热稳定性随ILs-MPEG侧链长度增加均呈先增加后减小的趋势.其中,ILs-MPEG800能有效降低PLA的Tg,但对PLA的热稳定性影响最小.

Effects of the ILs-MPEG on Glass Transition Temperature and Thermal Stability of PLA

The ILs-MPEG,a series of imidazolium ionic liquid,containing MPEG side chain with different length were incorporated into PLA to prepare the PLA/ILs-MPEG blend samples by melt-blending.The dispersion of ILs-MEPG in PLA matrix was observed by SEM,and then the plasticization effect and thermal stability of ILs-MPEG on PLA were investigated by differential scanning caborimetry(DSC) and thermo gravimetric analysis(TGA) respectively.The results showed that ILs-MPEG could be dispersed in PLA matrix even,but the dispersion decreased with the length of MPEG side chain increasing.The glass transition temperature(Tg) of PLA was effectively decreased with addition of ILs-MPEG due to the plasticization effect of ILs-MPEG,however,the thermal stabilities of PLA increased first and then decreased with the length of MPEG side chain increasing.In all of ILs-MPEG,the ILs-MPEG800 decreased Tgof PLA apparently,and had the least influence on PLA thermal stability.