Preparation And Properties Of Eucommia Ulmoides Gum Shape Memory Composites

Shape memory polymer(SMP)is a kind of polymer that can sense stimuli in external environment,such as temperature,electricity,light,magnetism,water and PH,and respond to stimuli by changing its state parameters.Before the appearance of SMP,smart materials are mainly composed of metal shape memory materials and inorganic non-metal shape memory materials.Compared with the former two kinds of smart materials,SMP has many potential technical advantages,such as excellent shape memory performance,high cost performance,easy processing and so on.Therefore,SMP is widely used in transportation,it industry,rocket aircraft,biomedical and other industrial products.Compared with other shape memory polymers,Eucommia gum(TPI)has the characteristics of double bond structure and crystal structure.Therefore,the development of Eucommia gum like shape memory composites has very important theoretical research needs and practical application prospects.In this paper,a serial of stimulus responsive shape memory composites were prepared using Eucommia ulmoides gum as matrix,by introducing other polymers,crystalline small molecules and functional fillers.The vulcanization properties,thermal properties,mechanical properties and shape memory properties of the composites were characterized.The relationship between microstructure and macroscopic properties of the composites was studied.The research contents of this paper are as followsFirstly,TPI/Polyacrylamide(PAM)composites and TPI/Sodium polyacrylate(PAAS)composites were prepared,and the effects of blending ratio on the vulcanization properties,mechanical properties,thermal properties and shape memory properties of TPI/PAM and TPI/PAAS composites were studied.The results show that the mechanical properties of TPI/PAM composites decrease with the increase of PAM content in TPI/PAM composites,and the shape fixation ratio of thermal stimulation response decreases from 86.58%to 85.47%,while the shape recovery rate increased from 92.47%to 95.12%.In the aspect of shape memory response to water stimulation,the shape fixation rate and shape recovery rate of the composite increased with the increase of PAM content.In TPI/PAAS composites,with the increase of PAAS content,the mechanical properties,crystallinity and shape memory properties of TPI/PAAS composites decreased;in the aspect of shape memory response to water stimulation,the shape fixation rate of TPI/PAAS composites remained basically unchanged,while the recovery rate of TPI/PAAS composites increased with the increase of PAAS content.Secondly,TPI/Stearic acid(SA)composites and TPI/Lauric acid(LA)composites were prepared.In this part,the effects of the amount of SA and LA on the mechanical properties,thermal properties and shape memory properties of TPI were studied.The results show that with the increase of SA and LA content,the mechanical properties of the composites decrease slightly,but the shape fixation rate of the composites can be improved;in the aspect of solvent stimulation response shape memory,the shape fixation rate and shape recovery rate of the composites increase with the increase of SA and LA content.Finally,a kind of electromagnetic shielding shape memory composites with thermal response and TPI composites with thermal and electrical stimulation response were prepared,namely TPI/Fe₃O₄ and TPI/Fe₃O₄/CNTs composites.The results show that:in TPI/Fe₃O₄ composites,with the increase of Fe₃O₄ content,the mechanical properties of the composites improve,the crystallinity decreases,and the electromagnetic shielding effect of the composites increases;in TPI/Fe₃O₄/CNTs composites,with the increase of CNTs content,the mechanical properties of the composites decrease slightly,the crystallinity increases,and the electromagnetic shielding effect increases.Especially,when the CNTs content increases by 12 phr,the electromagnetic shielding effectiveness can reach 24 d B,and the composite can recover from temporary shape to permanent shape in 5 seconds under 80 V DC voltage.