可生物降解高分子PLLA／PHB混合薄膜结晶性的研究

The Study of Crystallinity of Biodegradable Polymer Poly(L-lactide) and Polyhydroxybutyrate Blend Film

利用掠入射X射线衍射法(GIXD)对PLLA和PHB混合制成的薄膜进行研究。通过改变两者的混合比、分子量、膜厚等参数,观察PHB的加入对混合薄膜中PLLA的结晶性的影响,并与相同条件下可以近似视为本体的滴膜进行对比。实验发现在升温结晶的过程中,PHB的加入明显地提高了混合薄膜中PLLA的结晶性,同时还降低了PLLA的结晶温度并提高了熔融温度。但是在本体中却没有观察到这一现象。相对于分子量较大的PLLA,分子量较小的PLLA与PHB混合后结晶性的提升更为显著。

PLLA and PHB blend film and cast film were studied by grazing incidence X-ray diffraction. In order to investigate the impact of the addition of PHB on the crystallinity of PLLA of the blend film, blend films of various mixture ratios, molecular weights of PLLA, and thicknesses were prepared. The results were compared with the cast film. It is found that the crystallinity of PLLA in the blend film is increasing sharply with the addition of PHB during thermosetting. The crystallization temperature is lowered dramatically and the melting temperature is raised simultaneously. However this phenomenon was not observed in the bulk, i.e. cast film. Comparing with the PLLA with higher molecular weight, the crystallinity of lower ones is increasing more significantly after blending with PHB.