EVA的形状记忆功能探讨

Study on Shape Memorizing Function of Ethyl Vinyl Acetate Copolymer

首先对形状记忆功能高分子的特性进行了分析,提出了形状记忆性能的评价指标,即形状回复率、形状固定率、形状回复速度等.并进一步探讨了乙烯醋酸乙烯基共聚物(EVA) 的形状记忆功能特性,研究发现,用过氧化二异丙苯(DCP) 可对EVA 进行适度交联,控制二者组分结构,从而控制EVA 的交联程度,可使EVA 具有优异的记忆功能特性,如形状回复率和形状固定率均可达95 % 以上;进一步分析了EVA 的化学结构,讨论了分子结构与形状记忆性能的影响,并结合DMTA等热分析技术,对交联EVA 的交联密度进行计算,结果表明EVA 的交联点间分子量随DCP 用量增加而下降,并且其交联程度与EVA 的记忆特性存在着某种内在的必然联系,进一步研究分析发现其形状固定性与室温和橡胶态模量的比值呈线性关系。

The characters of shape memorizing polymer were analyzed and some evaluations standard on it were proposed,such as shape recovered rate,shape fixed rate and shape recovered speed,etc. The shape memorizing function of the EVA plastic had been studied,the results indicated that the EVA plastics can be cross linked with DCP ,and the properly cross linked EVA will have a good shape memory properties, which shape recovering rate and shape fixed rate can be 95% or more. The structure of EVA was also analyzed and the relationship between shape memorizing properties and structure has been discussed. The result through DMTA analysis also indicates that the increasing content of DCP will decrease the molecular weight between the cross linkage point( c) of EVA. In additional, the study indicates that the shape fixed rate was linear to the ratio of melted modulus to room temperature modulus.