形状记忆高分子因其具有良好的形状回复效果，在航空、医疗等领域具有广泛的应用前景。常规（传统）的形状记忆高分子及其复合材料具有二重形状记忆效果。最新的研究表明，通过适当的结构变化，可以实现在一个形状记忆循环中记住两个或以上形状的多重形状记忆效果。结合前期工作，申请者提出，如果对形状记忆复合材料进行结构设计，可以使复合材料具有一维可逆冷膨胀的三重形状记忆性能（即在室温时为常态，在较高温度时一维热收缩而在较低温度时一维冷膨胀三种形态），从而弥补常规材料热胀冷缩的缺陷，达到线性膨胀系数可控的目的。为证实以上假说，本研究将以水性环氧树脂和第二相形状记忆高分子材料为基体，气相生长纳米碳纤维为填料，通过结构设计，制备一维冷膨胀三重形状记忆复合材料，并对其结构形态、形状记忆性能、膨胀系数等进行系统的研究，明确三重形状记忆复合材料一维冷膨胀的作用机理，为形状记忆复合材料的一维冷膨胀性能提供有效的理论依据。

Shape memory polymers (SMPs) have a wide range of applications in aerospace, medical and other fields due to its excellent shape recovery effect. Common (Conventional) SMPs and their composites have only a dual shape memory effect. While, recently researches show that the triple shape memory effect (TSME, ability of SMPs to memorize two temporary shapes in one shape memory cycle) can be achieved by molecular structure design or modification of SMPs. On the basis of our previous works, we suggest that one-dimensional reversible cold expansion TSME composites have one-dimensional negative thermal expansion coefficient at high temperature and positive thermal expansion coefficient at low temperature which can be achieved by appropriate molecular structure design or modification of the SMP composites. By this mean, the phenomenon of thermal expansion and contraction of the common materials can be overcome and controllable linear thermal expansion coefficient can be achieved. To confirm the above hypothesis, here, the triple shape memory composites will be prepared via molecular design by using waterborne epoxy resin and the second phase of SMPs as matrix, vapor grown carbon fiber as filler. The structure morphologies, shape memory properties, and thermal expansion coefficients of the VGCNF/WEP composites will be systematic studied. The mechanism of the one -dimensional reversible cold expansion of the composites will be ascertained, which offered an effective evidence for the linear cold expansion property of shape memory composites.