热塑性聚氨酯/聚乙烯醇共混体系的相态结构与阻隔性

This project studies the interface compatibility and hydrogen-bonding interaction between Thermoplastic Polyurethane (TPU) and Polyvinyl Alcohol (PVA). Based on that, TPU/PVA blends with excellent barrier property can be prepared by melt extrusion through blending of TPU with PVA which have high barrier property. No plasticizer is required for the preparation. We further investigate the dynamic evolution law of phase state of the blend and the dependence of barrier property on the phase state of the blend. Such TPU/PVA blends overcome the limitation of traditional TPU that has poor barrier property, and can be directly applied for the manufacture of envelope of light aerostat, which would avoid the monopoly of the foreign technology.

本项目紧紧围绕聚氨酯在阻隔性能方面的不足，主要研究热塑性聚氨酯（TPU）和聚乙烯醇（PVA）共混体系。研究聚合物两组分间氢键作用在增容方面所起的作用，以及氢键相互作用对材料的相态结构、结晶行为、气体阻隔能力的影响；揭示多层复合材料的界面相互作用对材料阻隔性能的影响。以此为基础，在无需增塑剂的条件下研究制备PVA多薄片状分布于聚氨酯基体内的TPU/PVA共混物，得到具有高阻隔性能的薄膜。本项目为高阻隔性聚氨酯薄膜制备寻求一条方便、经济的途径。

采用溶液共混法及熔融共混法分别制备了热塑性聚氨酯（TPU）／聚乙烯醇（PVA）及热塑性聚氨酯（TPU）／乙烯-乙烯醇共聚物（EVOH）共混材料。利用FTIR，DSC，TGA 及气体渗透仪研究了共混材料的氢键作用、结晶性、热稳定性和气体阻隔性。结果表明，TPU 与PVA 和EVOH分子间皆存在一定程度的氢键作用；随着共混体系中乙烯醇基团含量的增加，TPU的结晶峰逐渐减小，共混材料的阻隔性能明显提高；共混体系的结晶温度、结晶度及熔点则随着TPU含量的增加明显降低。