SBS改性甲壳型液晶高分子的力学性能与形状记忆行为

Mechanical Properties and Shape Memory Behavior of Mesogen-Jacketed Liquid Crystalline Polymers Modified with SBS

用溶液共混法将SBS分别改性甲壳型液晶高分子PBPCS、PMPCS、PDCHVT、Pbi PCS,得到4种共混改性薄膜材料。通过差示扫描量热分析法测试共混材料玻璃化转变温度及光学显微镜观察薄膜表面形貌,表明甲壳型液晶高分子与SBS属于不相容组分。动态力学热分析(DMA)和力学性能测试表明,随着SBS含量的增加,改性薄膜的储能模量降低,但韧性增强,拉伸强度和断裂伸长率明显提高。DMA循环形状记忆测试表明,加入SBS改性后,PMPCS、Pbi PCS的形状记忆回复率有较大提高,SBS/PBPCS (5/5)、SBS/PDCHVT (5/5)薄膜有较好的综合形状记忆性能,其中SBS/PBPCS (5/5)长方形薄膜(25 mm×5 mm×0. 2 mm)拉伸强度为2 MPa,断裂伸长率为400%,形状记忆固定率为75%,形状记忆回复率为99%。

Mesogen-jacketed liquid crystalline polymers( MJLCPs),such as PBPCS,PMPCS,PDCHVT and PbiPCS,were modified with SBS by solution blending,and four kinds of blend films were obtained. The glass transition temperature of the blends and the surface morphology of the films were observed by DSC and optical microscope. The results show that the MJLCPs and SBS are incompatible. The DMA test and mechanical performance test show that,the storage modulus of the blend-modified films may be reduced,however the toughness,the tensile stress at break and fracture tensile ratio of the blend-modified films will be significantly improved with increase of the SBS content. DMA shape memory cyclic testing results indicate that the shape memory recovery ratios of PMPCS and PbiPCS become better because of the addition of SBS,SBS/PBPCS( 5/5) and SBS/PDCHVT( 5/5) films have good shape memory performance. The tensile stress of SBS/PBPCS( 5/5) rectangular film( size: 25 mm × 5 mm × 0. 2 mm) is 2 MPa,the fracture tensile ratio is 400%,the shape memory fixation ratio is 75%,and the shape memory recovery ratio is 99%.