| Shape Memory Polymer?SMP?is a new type of smart material.The realization of multi-functionality based on shape memory effect to meet specific needs of different engineering applications is the major trend for the development of SMP development in the future.In the current field of electronic engineering,flexibility,intelligence,portability,and low cost are the major directions for its development.There is an urgent need for smart materials such as SMP.However,the insulation of SMP has greatly limited its application in the field of electronic engineering.Therefore,it is most significant to enable SMP with conductive property in promoting the development of SMP in the field of electronic engineering.Due to the problems of conductive shape memory composites prepared by with composite materials technology,such as poor compatibility of the conductive phase and the polymer matrix,difficulty in uniform distribution of the conductive filler in the polymer matrix,and failure to form an effective connection with the matrix,etc,interpenetrating polymer networks?IPN?technology was used in this dissertation to introduce conductive macromolecule chains of conductive polyaniline?PANI?into the three-dimensional molecular network structure of epoxy shape memory polymers?EP?by means of the synchronization method and stepwise method,respectively.PANI/EP intrinsically conductive SMPs with IPN structure as well as both electrical and shape memory properties were prepared.Thermogravimetric analyzer,differential scanning calorimeter,fourier transform infrared spectrometer,scanning electron microscope,and four-probe tester were used to investigate the thermal properties,characteristic functional groups,microstructure,electrical conductivity and shape memory performance of the prepared materials.The specific contents of the paper are as follows:?1?Preparation and properties study of PANI:PANI doped with sulfuric acid?H2SO4?was synthesized by solution polymerization;DBSA-doped PANI was prepared with DBSA as doping acid by solution polymerization,emulsion polymerization and re-doping emeraldine base form of PANI respectively.Analysis and test results indicated that the molecular chain of PANI were successfully doped with H2SO4 and DBSA and showed conductivity property;The conductivity of H2SO4doped PANI was 7.00×10-1 S/cm,and the conductivity of DBSA-doped PANI prepared by solution polymerization,emulsion polymerization and re-doping emeraldine base form of PANI were 1.30×10-1 S/cm,1.74×10-1 S/cm and 1.24×10-2S/cm respectively.For PANI synthesized by solution method,the conductivity of PANI doped with inorganic acid was higher than that of PANI doped with organic acid,but the solubility of PANI doped with H2SO4 was very poor compared to DBSA-doped PANI.For the PANI doped with DBSA,the conductivity of the PANI synthesized in this experiment was higher than that of the PANI prepared by the re-doping method.?2?Preparation based on sequential IPN and performance study of PANI/EP intrinsically conductive SMP with IPN structure:DBSA-doped PANI prepared by the emulsion polymerization method and re-doping emeraldine base form of PANI respectively was a component of IPN,and EP was another component.PANI/EP semi-IPN intrinsic conductive SMPs were synthesized.The materials formed by PANI prepared with the method of emulsion polymerization and EP possessed conductive properties,and the conductivity was 1.53×10-4 S/cm.The shape memory performance was good.The materials recovered to the original shape fully.There was no reaction between PANI prepared by emulsion polymerization and EP matrix,and there was only one glass transition in the conductive SMP and no obvious phase separation was observed.The scanning electron microscope image of the material profile was flat and had no visible disperse phase.The results showed that the IPN structure was formed in the material.The material formed by the PANI prepared by the re-doping method and EP substrates also had conductive properties(the conductivity was 2.95×10-8S/cm)and shape memory effect.However,the thermal performance test result showed that there was two glass transitions in the material and phase separation;the morphology of the cross-section of the scanning electron microscope had obvious particles,and it was presumed that no IPN structure was formed in the material.?3?Preparation based on simultaneous IPN and performance study of PANI/EP intrinsically conductive SMP with IPN structure:the PANI/EP semi-IPN intrinsically conductive SMPs doped with H2SO4?inorganic acid?and DBSA?organic sulfonic acid?were prepared by the simultaneous method.The analytical test results indicated that both materials prepared by the simultaneous method exhibited conductive properties.The conductivity of the two materials were 1.31×10-5 S/cm and 6.70×10-6S/cm,respectively,and both materials showed good shape memory performance,which recovered to the original shape fully.The respective synthesis reaction routes of PANI and EP did not interfere with each other;there was only one glass transition and no obvious phase separation for the two conductive SMPs.The scanning electron microscope morphology of the fracture surfaces were homogeneous structure,indicating that both of the prepared materials were IPN structures.In summary,this paper introduce the conductive properties of PANI and the shape memory performance of SMP into the same polymer,thereby realizing the preparation of PANI/EP intrinsically conductive SMP of IPN structure,and useful exploratory work for the application of SMP in the field of electronic engineering was explored.At the same time,it also provided a new method for the multifunctional research of SMP. |
PDF Full Text Request