热塑性聚氨酯/聚己内酯共混物的形状记忆和力学性能

Shape Memory and Mechanical Properties of Polyurethane/Polycaprolactone Blends

利用简单的熔融共混制备得到不同组分比的热塑性聚氨酯(TPU)/聚己内酯(PCL)共混体系,研究了两相组分比的变化对共混材料相形态、形状记忆性能和力学性能的影响。偏光显微镜观察发现,随着结晶相PCL含量的增加,其逐渐从分散相过渡至连续相再发展为基体相。热性能测试结果表明TPU的加入对PCL的熔融行为影响甚微,整个共混体系基本表现出与PCL一致的熔点。形状记忆性能测试发现共混材料的形状记忆性能表现出明显的组分依赖性,并在组分比为50%/50%性能达到最优(R_r=91%,R_f=96%)。而力学测试结果表明,PCL的加入既不会显著劣化TPU原有的拉伸强度,还能进一步提高其断裂伸长率。

Thermoplastic polyurethane（TPU）/polycaprolactone（PCL）blends with different compositions were fabricated through melt blending,and the influence of composition on phase morphology,shape memory and mechanical properties was investigated.Polarized light micrographs display the evolution of PCL phase from dispersed to continuous domain,and finally into the matrix with the increase of its content.DSC results reveal that the melting behaviors of TPU/PCL blends tend to be similar to that of pure PCL.The shape memory properties of TPU/PCL blends are strongly governed by the compositions,and the best shape memory performance（R_r=91%,R_f=96%）is achieved when 50% PCL is introduced.Stretching tests display that the elongation at break is gradually improved with increasing the PCL content,while the tensile strength is not deteriorated distinctly.