聚乳酸/矿物填料复合材料的示差扫描量热研究

通过熔融共混法制备了一系列聚乳酸(PLA)/矿物填料复合材料.采用示差扫描量热(DSC)研究了含有碳酸钙(CaCO3)、蒙脱土(MMT)和凹凸棒土(AT)的聚乳酸复合材料在不同热历程中的结晶和熔融行为.研究发现,MMT和AT对PLA的慢速降温结晶无明显影响,而碳酸钙在慢速降温过程中能够有效促进PLA结晶;在2.5 K/min的降温速率下,结晶热焓随碳酸钙含量增加而增加;填料种类和含量会对复合材料升温过程的冷结晶和熔融产生较大影响,低含量矿物填料主要对PLA的冷结晶起成核作用,其中MMT成核效果最好.较高含量下不同填料会对PLA晶体形态产生影响,从而得到多样的DSC曲线变化.

EFFECT OF MINERAL FILLERS ON CRYSTALLIZATION AND MELTING BEHAVIOR OF POLY(LACTID ACID)/MINERAL FILLER COMPOSITES

A series of poly(lactid acid)(PLA)/mineral filler composites have been prepared by melt blending.Crystallization and melting behaviors of PLA composites containing calcium carbonate(CaCO3),montmorillonite(MMT) and attapulgite(AT) have been studied by differential scanning calorimetry(DSC),respectively.The results exhibited that MMT and AT did not obviously influence the slow-cooling crystallization of PLA,whereas CaCO3 effectively facilitated the crystallization of PLA in this process.The crystallization enthalpy(△Hc) increased with increasing the content of CaCO3 at a cooling rate of 2.5 K/min.Moreover,the type and content of the fillers played an important role in the cold crystallization and melting remarkably.Low-content mineral fillers would promote the nucleation in the cold crystallization of PLA,among which MMT was the best effective.Meanwhile,different mineral fillers with relatively high contents would affect the crystal structures of PLA,yielding various types of DSC curves.