Preparation And Study On The Electrical Properties Of Polyaniline/Polyurethane Semi-interpenetrating Network Elastomer

Compared with traditional material,flexible electronic material is lighter and more intelligent.With their special electrical properties and deformability,flexible electronic material has been applied widely in many fields,such as information,energy,and medical treatment.Researchers have developed a variety of flexible electronic material,but the material can not have the performance of both large deformation and high conductivity,which greatly limits the use.How to prevent the conduction path from being destroyed under large deformation is the key to solving this problem.Through designing the structural,part of the conductive polyaniline(PANI)is introduced into the macromolecular chain of the elastic matrix in a non-covalent manner.Under large deformation,PANI would distributes uniformly in the matrix,and the conductive path can keep unbroken.This is an ideal strategy to solve problem.In this paper,the soluble PANI-β-CD polyrotaxane was obtained by polymerization of the inclusion complex of N-phenyl-p-phenylenediamine(PPD)and β-cyclodextrin(β-CD).Then the β-CD of the polyrotaxane was used as the crosslinking agent to construct a semi-interpenetrating polymer network in which polyurethane elastomer(PUE)acts as the cross-linking network and PANI plays the role of linear molecule.The specific content is as follows:(1)Host-guest inclusion complexes were prepared with aniline and PPD acting as the guest respectively,and β-CD acting as the host.FT-IR and 1H-NMR proved the inclusion ofβ-CD to aniline and PPD,respectively.The methods of Job’s curve and phase solubility proved that both aniline and PPD formed inclusion compound with β-CD at a ratio of 1:1.Through 1H-NMR characterization and structural analysis of the inclusion complex,it was determined that in the inclusion complex,the amino groups of aniline and PPD are outside the β-CD cavity,the benzene ring of aniline is in the cyclodextrin cavity,and the imino group of PPD and part of the benzene rings on both sides of the imino were enclosed by the cyclodextrin cavity.The influence of factors such as temperature,host-guest ratio,and standing time on β-CD including aniline and PPD was further studied.Due to the difference in structure and properties,the suitable inclusion conditions of the two kinds of guests were proved different.The controllable preparation of aniline-β-CD and PPD-β-CD inclusion complexes was successfully realized by adjusting the inclusion conditions.(2)Aniline inclusion complex(Aniline-β-CD)and PPD inclusion complex(PPD-β-CD)were used to polymerize,respectively.Characterizations such as FT-IR,1H-NMR and XRD proved the polymerization of PPD-β-CD inclusion complex,and it was confirmed that doping with p-toluenesulfonic acid(PTSA),the PANI-β-CD polyrotaxane was prepared.The polyrotaxane can transfer to pseudopolyrotaxane by dedoping,and the transformation is reversible by doping.The relationship between β-CD content in polyrotaxane and polymerization conditions was further studied,and the results showed that β-CD content in polyrotaxane can be adjusted by the amount of PTSA and oxidant,and its mass fraction can be controlled between 40%-65%.The solubility experiment confirmed that PANI-β-CD polyrotaxane can be dissolved in N,N’dimethylforamamide(DMF),and the solubility can reach 6.52 g at 80℃.The PANI-β-CD polyrotaxane was successfully prepared,and the polyrotaxane has a good solvent,which makes the polyrotaxane can be used in the synthesis of polyurethane(PUE).(3)The β-CD of PANI-β-CD polyrotaxane was used as the cross-linking agent in the synthesis of PUE to construct the PANI/PUE semi-interpenetrating network.Characterizations such as FT-IR,XRD,low-field nuclear magnetic crosslinking density meter proved the formation of the semi-interpenetrating network.The analysis by 3D confocal laser microscope proved that when the semi-interpenetrating network elastomer deformed,PANI was still uniformly dispersed in the elastomer.After blending with soluble PANI,the semi-interpenetrating network elastomer had conductive properties.When the content of soluble PANI is 20%,compared with the elastomer without the structure,the conductivity of the elastomer containing the semi-interpenetrating network increased from 9.26×10-3 S·cm-1 to 4.35×10-2 S·cm-1.The resistance change of the conductive elastomer under deformation was tested.After stretching 300 times at the tensile rate of 400%,the resistance and the resistance change value of the elastomer containing semi-interpenetrating network are both smaller than those without the semi-interpenetrating network stracture because of the more complete conductive path.The PANI/PUE semi-interpenetrating network elastomer is prepared,and it is proved that the semi-interpenetrating network structure improves the stability of the electrical properties of the conductive elastomer under large deformation.