Study On Preparation And Properties Of Sisal Fiber Shape Memory Composites

With the further research and development,the potential application of SMP has reflected every aspect in the real life.It shows a broad application prospect in the auto parts self-healing,the kitchen utensils,electronic switches,sensors,intelligent packaging,membrane separation materials,products for the disabled,national defense materials and biomedical material.Thus the preparation and properties of SMP materials has important theoretical and practical significance.For common the shape memory polymer,shape recovery temperature is higher,which is generally higher than the normal human body temperature and too much heat often damage the human body organs and tissues.According to the development direction of SMP,from renewable,biodegradable,low temperature response,good biocompatibility and other aspects,based on sisal nano cellulose as substrate,we preparate two kinds of biomass shape memory polymer with good response performance in this paper.For part one,with sisal as raw material,obtained the chloroacetic acid modified MSF-g-COOH nano cellulose.With graphite as raw material,using the improving Hummers method to oxidate the graphite,combined with ultrasonic separation to preparate the graphene oxide(GO).Acting MSF-g-COOH nano cellulose as the matrix and the GO as reinforced phase,was obtained the layered structure of the GO/MSF-g-COOH nano composite membrane through a simple suction filter method.The results showed that the GO/MSF-g-COOH composite film has excellent mechanical properties,such as the tensile strength and tensile modulus of 181.7 MPa and 9.87 GPa,respectively.At the same time,It has good shape memory performancein the water environment.Through the establishment of the numerical simulation,the cause of the shape memory response curves have been discussed,so as to explain the mechanism of shape memory reply.The curve of the numerical simulation of the Rr-t curve is almost entirely coincidence with experimental data and the determination coefficient is 0.997.For part two,using sisal nano cellulose fiber(NSF)and polyethylene glycol(PEG)as matrix,citric acid(CA)as crosslinking agent,was obtained an interpenetrating network shape memory nanocomposite NSF/PEG/CA through evaporation induced independent(EISA).The test results that the water absorbing and swelling volume resistance of the NSF/PEG/CA composite has been improved through the crosslinking of citric acid,and it can still maintain good mechanical properties in spite of soaking.The study found that NSF/PEG/CA has excellent water response shape memory performance,but the water response regeneration rate reduces with the increase of crosslinking degree.For crosslinking NSF/PEG/CA interpenetrating polymer network,the greater the degree of crosslinking,the free volume is smaller,resulting in the low solvent diffusion velocity and the slow corresponding response speed.