Design And Experimental Research On Thermotropic Shape Memory Effect Measurement Device

Shape memory polymers(SMP)are polymeric materials that can return to their original shape induced by an external stimulus,such as temperature,humidity,light or magnetic field.SMP are widely used in microsystems,biomedical,deployable structures and deformable structures in aerospace.The preparation and application of SMP involve the efficient and accurate measurement of its shape memory recovery performance.So,the development of equipment to measure and characterize SMP’s recovery performance has both theoretical significance and engineering application value.In this paper,a new characterization method to investigate the recovering process based on stretch-recovery of SMP is proposed according to the recovery behavior and present characterization method of thermal SMP.Based on the method,a device determining the shape recovery effect of SMP is developed,and systematic experiments were carried out with it.The main works and results include:(1)A characterization method for shape memory recovery based on stretching-recovery deformation process is established,so as to characterize the shape retaining of thermallyinduced SMP.(2)A device characterizing SMP’s shape retaining is developed,which composes of deformation unit,temperature control unit and data acquisition unit.With the device,the thermally-induced shape recovery process of SMP can be demonstrated completely,and the data related to shape recovery rate can be acquired.Then,the shape recovery performance of SMP is able to be quantified and analyzed according to collected data.(3)PPC/PLA blends with thermally induced shape memory was prepared by melt blending process.The thermal properties and micro-morphology of the blends are tested and characterized with DSC,TG,SEM and other testing methods,which provides the basis for the characterization and analysis of memory recovery rate of PPC/PLA blends.(4)The shape retaining property of PPC/PLA blends is characterized with the home-made device,water bath measurement and DMA measurement to verify the reliability of the homemade device.The shape memory experiment shows that the higher the deformation temperature is,the better the shape memory recovery of PPC/PLA is,and the shape recovery of PPC/PLA stop increasing when the deformation temperature reached 60℃;Besides,the shape memory recovery of PPC/PLA was increased with the increase of tensile rate,and the shape recovery of PPC/PLA stops increasing when the tensile rate reached 0.5 mm/s.