发泡CaCO3/杜仲胶形状记忆复合材料的制备与表征

天然杜仲胶的反式有序性结构使其具有较强的结晶能力，交联程度较低时可用作形状记忆材料。本文以热膨胀物理微球Expancel 920DU40为发泡剂制备了发泡CaCO₃/杜仲胶（EUG）形状记忆复合材料，采用SEM、FTIR、DSC、DMA和万能材料试验机等对Expancel 920DU40的组分及受热膨胀特性和不同交联程度的CaCO₃/EUG形状记忆复合材料的结晶熔融行为、微观形貌、形状记忆行为及力学性能进行了表征。结果表明，Expancel 920DU40的外壳为丙烯腈均聚物或与其他单体的共聚物，内部为液态烷烃； CaCO₃/EUG形状记忆复合材料的力学性能与其交联程度和发泡程度有关；随着交联程度的增加，EUG的结晶和熔融温度降低，形变率、形状固定率和形状回复率均降低，当S用量为0.8 g时形状记忆性能最佳；调控交联程度可以获得具备不同形状记忆能力的CaCO₃/EUG形状记忆复合材料。

Preparation and characterization of foamed CaCO3/eucommia ulmoides gum shape memory composites

Natural eucommia ulmoides gum (EUG) is in crystallized state due to its ordered trans-molecular structure, and it can be used as shape memory materials with low crosslink density. The foamed CaCO₃/EUG shape memory composites was prepared using Expancel 920DU40 as the foaming agent. The components and foaming properties of Expancel 920DU40 and the crystallization and melting behaviors, microstructure, shape memory properties and mechanical performance of foamed CaCO₃/EUG shape memory composites were measured by SEM, FTIR, DSC, DMA and the universal material testing machine. The results show that the shell of Expancel 920DU40 is composed of acrylonitrile and its copolymer with other monomer, and its interior is filled with liquid alkanes. The mechanical performance of foamed CaCO₃/EUG shape memory composites is related to their crosslink density and foaming extent. The melting temperature and crystalline degree of EUG and deformation rate, shape fixity ratio and shape recovery ratio of foamed CaCO₃/EUG shape memory composites all decrease with the increase of crosslink density. When sulfur content is 0.8 g, the foamed CaCO₃/EUG composite exhibites the best shape memory properties. The foamed CaCO₃/EUG shape memory composites with various shape memory abilities can be prepared via controlling their crosslink density.