溶剂诱导的聚乳酸/聚乳酸衍生物共结晶行为

通过溶液浇铸法制备不同组分的左旋聚乳酸(PLLA)和聚(L-2-羟基-3-甲基丁酸)(PL-2H3MB)共混物。运用差示扫描量热仪(DSC)、偏光显微镜(POM)、广角X射线衍射(WAXD)和热重分析仪(TGA)分析共混物的结晶、熔融行为和热稳定性。通过观察到DSC加热曲线中新的熔融峰判断PLLA和PL-2H3MB共晶的形成,共晶显著提高PLLA起始结晶温度和WAXD曲线中特征衍射峰的变化,证实了溶液浇铸共混物中的共结晶现象。同时,共混物中PL-2H3MB和PLLA还表现出优于单组分PLLA和PL-2H3MB的热稳定性。PLLA和PL-2H3MB的共结晶行为可能为调控PLLA的热稳定性、力学性能以及降解性能提供了一种新的潜在方法。

Solution-Induced Co-crystallization in Poly(lactic acid)/Substituted Poly(lactic acid)Blends

The blends of poly(L-lactic acid)(PLLA)and poly(L-2-hydroxy-3-methylbutanoic acid)(PL-2H3MB)with different compositions were prepared by solution casting.The crystallization,melting and pyrolysis properties of the blends were investigated by differential scanning calorimetry(DSC),polarized optical microscope(POM),wide angle X-ray diffractometry(WAXD)and thermogravimetric analysis(TGA).The formation of PLLA and PL-2H3MB co-crystals was speculated due to the observation of the new melting peak in DSC first heating profile.The co-crysals significantly increased the initial crystallization temperature of PLLA and the characteristic diffraction peaks in WAXD profile were also shifted,which both confirmed the co-crystallization phenomenon in solution casting blend.At the same time,the thermal stability of PLLA/PL-2H3MB blends was better than that of neat PLLA or PL-2H3MB.The co-crystallization behavior of PLLA and PL-2H3MB may provided a new potential method to regulate the thermal stability,mechanical properties and degradation properties of PLLA.