酯化淀粉薄膜中增塑剂与淀粉分子间相互作用的研究

Effect of Diethyl Phthalate on the Structure and Thermal Stability of Starch Ester Film

摘要:

采用酯化淀粉以邻苯二甲酸二乙酯（DEP）为增塑剂，经流延法制备了酯化淀粉薄膜。通过扫描电子显微（SEM）、傅立叶变换红外光谱分析仪（FT-IR）、小角/广角X射线散射（SAXS/WAXS）等现代分析技术对酯化淀粉薄膜的结构及增塑剂DEP与淀粉分子间的相互作用变化进行了系统分析。结果表明，随着增塑剂DEP含量的增加，增塑剂DEP分子减弱了淀粉分子内/间相互作用力，且导致了无定形区域中淀粉分子形成部分排列更规整的微晶结构，促使淀粉分子形成有序微区，但有序微区结构尺寸Rg在37 nm~38 nm之间变化不大。通过调节酯化淀粉薄膜中增塑剂DEP含量，可控制增塑剂分子与淀粉分子间的相互作用、淀粉分子链段在薄膜中微区的有序排列程度及其规整程度，为设计抑制增塑剂迁移的酯化淀粉薄膜材料提供了基础数据。

Abstract:

The starch ester film was prepared by solvent-casting method using Diethyl phthalate (DEP) as plasticizer. The changes in structure of the starch ester film and the intermolecular interaction between the molecule of DEP and starch ester were investigated by scanning electron microscope (SEM), attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR), and small-wide angel X-ray scattering (SAXS/WAXS). The results indicated that with the increase of DEP amount in the film, the inter- and intra-molecule interaction among the molecules of the starch ester was weakened and a greater amount of ordered microcrystalline structures was formed in the amorphous regions which resulted in the formation of more ordered aggregation microstructures. But the Rg of the microstructure remained 37~38 nm. Thus, intermolecular interaction, the order of molecular arrangement and aggregation structures of the starch ester can be controlled by adjusting the DEP content in the starch ester film, which provides fundamental data for the design of the starch-based materials with restrained plasticizer migration.