线性单体对热致形状记忆环氧树脂的改性

Thermo-responsive shape memory epoxy modified by linear monomers

针对航天用纤维增强形状记忆复合材料对基体韧性、耐热性和成型工艺性等方面的要求,采用癸二酸(SA),超支化聚酯(HBP)和聚醚多元醇缩水甘油醚(PPGE)等线性单体对形状记忆环氧树脂(SME)进行了改性研究。研究表明,使用SA将长脂肪链引入SME的改性效果最佳。相对于空白对照组,树脂的形状记忆回复时间缩短48.1%;赋形温度下的储能模量降低98.76%;室温下拉伸强度提高24.1%,拉伸弹性模量仅降低13.7%,断裂伸长率提高121.3%。少量添加HBP可以改善分子的网状结构,但HBP过量时,分子链段则重新向线性转变。加入HBP虽可改善树脂室温下的力学性能,但也导致赋形温度下的较高刚度。PPGE虽可加长柔性链段,但会降低体系的反应速率,改性效果较差。此外,SA改性可以有效延长体系的工艺窗口时间,HBP反之,PPGE则对工艺性影响较小。

In order to meet the requirements of fiber-reinforced shape memory composites for aerospace applications in terms of matrix toughness,heat resistance and molding processability,the shape memory epoxy resin(SME)was modified by linear mono‐mers such as sebacic acid(SA),hyperbranched polyester(HBP)and polyether polyol glycidyl ether(PPGE).It is shown that the best modification effect is achieved by introducing long aliphatic chains into SME using SA.Compared with the control group,the shape memory recovery time of the resin is shortened by 48.1%;the storage modulus at the deformation temperature is reduced by 98.76%.The tensile strength at room temperature is increased by 24.1%.The tensile modulus is reduced by only 13.7%.The elongation at break is increased by 121.3%.A small amount of HBP can improve the molecular network structure.But the molecular chain segments revert to linear when HBP is in excess.The addition of HBP improves the mechanical properties of the resin at room temperature,but it also leads to higher stiffness at the deformation temperature.PPGE lengthens the flexible chain segments,but it reduces the reaction rate of the system.The modification effect is poor.In addition,the modification of SA can effectively extend the process time of the system,while HBP has the opposite effect.PPGE has less impact on the processability.