Preparation And Application Of Polyaniline Nanocomposite

Electrospinning is a relatively simple method to prepare polymer nanofiber material through high-voltage static electricity as the driving force.The study on the microstructure and electric properties of electrospun polyaniline(PANI)nanofiber is helpful to accelerate the application of conductive polymer nanofiber material in multiple fields such as electronic,energy and sensor,etc.In this paper,conductive PANI/sodium alginate(SA)nanofiber with well conductivity and mechanical property was prepared by electrospinning method.The main contents and results include the following three parts:(1)PANI was synthesized by the method of in-situ polymerization in the water phase.PANI,SA and polyvinyl alcohol(PVA)were chosen as the main raw materials to prepare PANI/SA/PVA nanofiber membrane by electrospinning method.Effects of the concentration of PANI and proportion of SA/PVA on the morphology and size of the nanofiber membrane were studied.The optimal condition for spinning was obtained with 0.4 wt% PANI,3:7 SA/PVA proportion,22-24 cm spinning distances,-2 k V negative voltage and 14-16 k V positive voltages.The structure and properties of the as-prepared nanofiber membrane were characterized by XRD,FTIR,TG,the water resistance test,mechanical property test and conductivity test.The results showed that the crystal structure of the as-prepared nanofiber membrane was affected by a certain amount because of the mixture of the raw materials.The intermolecular forces were changed to a certain extent and the hydrogen bonding was produced between the raw materials of the as-prepared nanofiber membrane.The thermal stability of the as-prepared nanofiber membrane became more stable because of the existence of PANI and SA.Due to the addition of PANI,the decomposition temperature of the as-spun nanofiber membrane was increased.The introduction of PANI exhibits a beneficial effect on the thermal stability.The water resistance,mechanical properties and conductivity of the as-spun nanofiber membranes were relatively poor.(2)In order to improve the mechanical property and water resistance,the crosslinking modification of the PANI/SA/PVA nanofiber membrane was required,and Ca Cl2 was chosen as the crosslinking agent.Effects of the concentration of Ca Cl2 and crosslinking time on the structure and properties of the nanofiber membrane were studied.The optimal condition was obtained with 3 wt% Ca Cl2 for 24 hours.After crosslinking modification of the as-prepared nanofiber membrane,the water resistance was increased significantly,the swelling rate and dissolve-loss rate were reduced,and the contact angle was increased.In addition,the mechanical property of the as-prepared nanofiber membrane after crosslinking modification was improved to a certain extent,but the conductivity was not changed in nature.The XRD and FTIR showed that the crystallinity of the as-spun nanofiber membrane after crosslinking modification was reduced slightly when the crosslinking time is shorter(≤24 h).When the crosslinking time is longer(>24 h),the strengths and forms of infrared characteristic peak were changed significantly.The TG and DTG showed that the thermal stability of the as-spun nanofiber membrane after crosslinking modification was increased a little.(3)In order to improve the conductivity of the as-prepared PANI/SA/PVA nanofiber membrane,dispersant NNO was added to the spinning dope.Water dispersible PANI,SA and PVA were chosen as the main raw material to prepare PANI-NNO/SA/PVA nanofiber membrane by electrospinning method.The effect of the proportion of PANI-NNO/SA-PVA on the morphology of the nanofiber membrane was studied.The optimal condition for spinning was obtained with 4:6 PANI-PVA/SA-PVA proportion,22-24 cm spinning distances,-2 k V negative voltage and 16-18 k V positive voltages.The XRD and FTIR showed that the crystallinity of the nanofiber membrane was decreased and the forms of infrared characteristic peak were changed significantly because of the existence of a large number of water dispersible PANI.The TG and DTG showed that the thermal stability of the nanofiber membrane was increased because of the existence of PANI-NNO.Compared with PANI/SA/PVA nanofiber membrane,the conductivity of the PANI-NNO/SA/PVA nanofiber membrane was improved one or two orders of magnitude.