氯化镁增塑改性聚乙烯醇

以氯化镁为增塑剂, 采用流延法制备了增塑改性聚乙烯醇(PVA). 研究了氯化镁与PVA的相互作用以及氯化镁增塑改性PVA的结晶性能、 热性能和机械性能. 研究结果表明, 氯化镁能与PVA大分子发生较强的相互作用, 从而破坏PVA分子链内和链间的氢键, 降低PVA的结晶度. 氯化镁对PVA的热性能影响显著, PVA在加入氯化镁后的热分解过程由纯PVA的两段失重过程转变成三段失重过程. 氯化镁可有效增塑PVA, 其玻璃化转变温度降低, 拉伸强度下降, 断裂伸长率上升, 储能模量下降.

Properties of Poly( vinyl alcohol) Plasticized by Magnesium Chloride

The plasticized poly(vinyl alcohol)(PVA) films were prepared by the casting method using magnesium chloride(MgCl2) as the plasticizer. The interaction between MgCl2 and PVA was analysised by Fourier transform infrared(FTIR) spectroscopy. The change of the crystalline and thermal properties of PVA with the content of MgCl2 were measured by X-ray diffraction measurements(XRD), differential scanning calorimetry and thermogravimetric analysis(TGA) respectively. The mechanical properties were measured as a function of MgCl2 content. It was found that MgCl2 could form considerable interaction with PVA and form a complex. The XRD showed that the crystallinity of PVA film decreased with the content of MgCl2, which would be ascribed to the interaction of MgCl2 with PVA molecules, causing the destroying of the intra/inter molecular hydrogen bonding between PVA chains. The glass transition temperature of PVA also decreased with the content of MgCl2. The TGA results show that the thermal stabilities of PVA decreased with the addition of MgCl2 and the thermal degradation process was changed. The mechanical testing showed that PVA become soft, with lower tensile strength and higher elongation at break after modification.