形状记忆PCL/CB复合材料的制备及其光致弯曲变形行为

Preparation of shape memory PCL/CB composites and its photo-triggered bending deformation behaviors

为了制备具有远程可控变形且性能优越的形状记忆聚合物,采用巯基-烯点击化学法制备了PCL/CB复合材料,并用FTIR、DSC、1 H NMR和DMA对复合材料的结构、热性能以及形状记忆特性等进行表征。结果表明:交联复合材料薄膜的热转变温度为50℃,且当预拉伸的复合材料薄膜受到100 mW/cm^(2)强度的激光照射时,CB颗粒吸收激光光子而产生光热转换且由于各向异性链松弛和应变能释放,致使上层薄膜在受到激光照射时,结晶熔融发生形状记忆效应而收缩,与此同时下层薄膜仍然处于玻璃态,上层薄膜的收缩力使PCL/CB复合材料薄膜朝着激光照射方向发生弯曲变形。同时,弯曲角度可以通过薄膜预拉伸应变量、激光照射时间以及薄膜厚度3个参数进行调控;当预拉伸应变为300%、薄膜厚度为0.4 mm时,最大弯曲角为164°。这种具备局部可编程行为的PCL/CB复合薄膜可为光响应SMP的变形模式提供新思路。

In order to prepare shape memory polymers with remote controllable deformation and superior performance,PCL/CB composites were prepared by thiol-ene click chemistry method,and their chemical structures,thermal properties and shape memory properties were characterized via FTIR,DSC,1 H NMR and DMA.The results indicate that the thermal transition temperature is 50℃,and when the pre-stretched composite film is irradiated by a 100 mW/cm^(2) laser,the CB particles absorb laser photons and produce photothermal conversion.Due to the relaxation of the anisotropic chain and the release of strain energy,the upper layer shrinks due to the melting of crystal regions when irradiated with laser,while the lower layer is still in a glassy state.The shrinkage force of the upper film causes the PCL/CB composite material film to bend and deform toward the direction of laser irradiation.At the same time,the bending angle can be controlled by three parameters:pre-stretch strain,irradiation time,and film thickness.When the prestretch strain is 300%and the film thickness is 0.4 mm,the maximum bending angle is 164°.The PCL/CB composite film with locally programmable behavior can provide new ideas for the deformation mode of light responsive SMP.