| Shape Memory Polymers?SMPs?are a new type of smart materials,with significant Shape Memory effects.At present,the conductive functionalization of SMPs is one of the important research contents of SMPs multi-functionalization.The development of SMPs materials with conductive properties can obtain multi-functional intelligent materials with both shape memory effect and conductive properties,thus promoting the application and development of SMPs in the field of electronic engineering.As for the problems existing in conductive shape memory polymer composites,such as poor compatibility between conductive fillers and matrix,uneven dispersion of conductive fillers in matrix,and complex preparation process,etc.In this paper,based on the the shape memory effect of flexible Ethylene/vinyl acetate copolymer?Ethylene-vinyl acetate copolymer,EVA?and rigid Polyvinyl chloride?Polyvinyl chloride,PVC?and the polymerization reaction of conductive Polyaniline?PANI?,the polyaniline raw material monomers were allowed to enter the molecular network gap of the matrix for in-situ polymerization when the EVA and PVC were swollen,and then the polyaniline/SMPs molecular composites with the coexistence of electrical conductivity and shape memory effect were perpared.The in situ polymerization of polyaniline/SMPs molecular composites and their electrical conductivity,shape memory effect,thermal properties,mechanical properties and microstructure were studied.The specific content of the thesis is as follows:?1?Preparation and properties study of polyaniline/ethylene-vinyl acetate molecular composite?PANI/EVA-MC?:PANI/EVA-MC was prepared,and the effects of aniline concentration,swelling time,oxidant concentration,oxidation time,pH value of oxidant solution and concentration of dopant hydrochloric acid on the electrical conductivity of the material were studied.The electrical conductivity of PANI/EVA-MC was 5.24×10-2 S·cm-1 according to the results of the optimum preparation parameters,and its room temperature conductivity was 10-3S·cm-1 after heating under 120°C.The results of microstructure analysis showed that PANI was successfully synthesized in the EVA matrix,and the microstructure of the section presented a continuous and uniform phase.It can be speculated that PANI formed a molecule-level mixture in the EVA matrix,and the thickness of the conductive layer of PANI/EVA-MC was about 20?m40?m.The results of thermal performance analysis showed that PANI macromolecular chain had good compatibility with EVA.The results of mechanical properties showed that the introduction of rigid PANI enhanced the strength of the matrix material.The results of shape memory performance showed that the shape memory performance of PANI/EVA-MC was similar to that of pure EVA,indicating that the introduction of PANI macromolecular chain had little influence on the shape memory performance of the EVA matrix.In addition,in the process of shape memory effect,the conductivity of PANI/EVA-MC at room temperature and glass transition temperature after tensile pre-deformation of 20%and 100%was 10-3 S·cm-1,and its conductivity remained at10-3 S·cm-1 after shape recovery with a pre-deformation temperature of room temperature,and its conductivity was 10-3 S·cm-110-5 S·cm-1 after shape recovery with a pre-deformation temperature of glass transition temperature.?2?Preparation and performance study of polyaniline/polyvinyl chloride molecular composite?PANI/PVC-MC?:PANI/PVC-MC was prepared,and the effects of aniline concentration,swelling time,oxidant concentration,oxidation time,pH value of oxidant solution and concentration of dopant hydrochloric acid on the electrical conductivity of the material were studied.According to the optimal preparation parameters,the electrical conductivity of PANI/PVC-MC was 4.26×10-2 S·cm-1,and its room temperature conductivity was 10-3 S·cm-1 after heating below 100°C.The results of microstructure analysis showed that PANI was successfully synthesized in the PVC matrix,and PANI did not form a single phase.It was speculated that the PANI macromolecular chain formed a molecular level mixture with the PVC network,and the synthesized PANI was within the depth range of 20?m50?m.The analysis results of thermal and mechanical properties showed that PANI macromolecular chain had good compatibility with the substrate PVC,but compared with PVC,the thermal stability and strength of PANI/PVC-MC decreased,which could be attributed to the swelling effect of aniline.The results of shape memory performance showed that PANI/PVC-MC had significant shape memory effect.In the process of shape memory effect,the conductivity of PANI/PVC-MC was 10-3 S·cm-1 after pre-deformation of 20%and 100%at room temperature and glass transition temperature and after heating recovery.To sum up,with flexible EVA and rigid PVC shape memory polymer matrix as the research object,through the polymerization reaction system of polyaniline and on the premise of maintaining the shape memory effect,the introduction of PANI macromolecular chain into the SMPs network structure can realize the conductive function of SMPs and obtain polyaniline/SMPs molecular composites,providing a simple and easy new method for the conductive function of solidified SMPs. |
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