聚乙烯醇多孔形状记忆材料的制备及性能

Preparation and properties of polyvinyl alcohol porous shape memory materials

为简化聚乙烯醇(PVA)发泡工艺,并开发一种新型多孔形状记忆高分子基材,采用物理发泡法和冷冻干燥法相结合的方法,制备得到具有均匀孔结构和良好热致形状记忆性能的PVA多孔形状记忆材料。研究了搅拌转速对PVA多孔形状记忆材料孔结构的影响,并探究了冻融循环次数对其结晶性能、力学性能、热稳定性能和热致形状记忆性能的影响。结果表明:搅拌转速为1500 r/min时,制备得到的多孔材料具有均匀且完整的孔结构;多次冻融循环可促进多孔材料内部PVA分子链的相互缠结,增加多孔材料的结晶度,改善其力学性能及热稳定性能。5次冻融循环后的多孔材料消除不可逆形变后,在80℃条件下,5 min内即可完全回复至初始形态。

In order to obtain a more convenient foaming process of polyvinyl alcohol(PVA),and to develop a new porous shape memory polymer materials.PVA porous shape memory materials with uniform pore structure and good thermal shape memory performance were prepared by physical foaming and freeze-drying methods.The effect of stirring speed on the pore structure of PVA porous shape memory material was studied,and the effects of freeze-thaw cycles on its crystallization,mechanical properties,thermal stability and thermally induced shape memory properties were explored.The results show that the porous material with uniform pore structure can be prepared at 1500 r/min.Multiple freeze-thaw cycles can promote the entanglement of PVA molecular chains in porous materials,increase the crystallinity of porous materials,and improve their mechanical properties and thermal stability.When the irreversible deformation is eliminated,the porous material after 5 freeze-thaw cycles can be completely recovered to its original form within 5 min at 80℃.