Study On Aggregation Behavior Of Polyacrylonitrile In Solutions And Preparation Of Polyaniline/Polyacrylonitrile Composite Films

PAN is always selected as polymer matrix composite due to its high strength, high abrasion resistance, photochemical stability and wearability. The aggregation behavior of PAN chain in solution has a significant impact on structure and mechanical properties of formation polymer, thus the aggregation behavior of PAN chain in solution was studied using UV-visible spectroscopy and fluorescent probe technique and more attention should be paid to the influences of solvent and non solvent on aggregation behavior of PAN solution. In addition, flexible polyaniline(PANI)/polyacrylonitrile(PAN) composite conductive films were prepared based on diffusion behavior of solvent/non-solvent in PAN films formation. The PAN1/PAN composite films exhibited good flexible and conductive properties. The main results are summaried as follows.1. The aggregation behavior of PAN solution was studied by UV-visible absorption spectroscopy. The influences of solvent, solution concentration, water content and aging time on aggregation behavior of polyacrylonitrile solution were studied in which DMSO, DMAc and DMF were used as solvents and water as non-solvent. The results show that the largest absorption intensity and maximum absorption wavelength increase in the order of DMAC, DMSO and DMF, which implies the enhance of interaction between PAN and the solvent molecules. With the increasing of PAN solution concentration, water contents and aging time, the largest absorption intensity and maximum absorption wavelength increase, which implies the more tight aggregation of PAN molecules.2. It is found that the -CN group in PAN chain can affect the photolysis of anthraquinone groups. Therefore, PAN-AAQN was prepared by introducing photolysised 1-aminoanthraquinone as fluorescent probe into the PAN chain. The photolysis of anthraquinone in PAN-AAQN solution was characterized by using of fluorescence spectroscopy. The conformational state and aggregation behavior of polyacrylonitrile were studied by observing the intensity variation in fluorescence emission spectrum for PAN-AAQN solutions. The results show that a novel fluorescent probe method was presented to study the aggregation behavior of PAN chain.3. The flexible polyaniline (PANI)/polyacrylonitrile (PAN) composite films were successfully prepared by permeation of the aniline monomers into the solution of PAN in dimethyl sulfoxide and one-step in-situ polymerization of aniline monomers from and in microporous PAN layer. The existence of a layered structure was shown by attenuated total reflection Fourier transform infrared spectroscopy, UV-visible spectroscopy and scanning electron microscopy. Good adherence between PANI and PAN benefited from the formation of a continuous gradient network in the film thickness along the capillary. The PANI/PAN composite film showed good flexible and conductive properties when the concentration of PAN and AN were 20%wt and l%wt respectively, 0.25 M ammonium persulphate solution (in 1M HC1 aqueous solution) as an oxidant and the polymerization time is 3h. The good mechanics property, thermal stability and fatigue resistivity of the resulting composite film were also observed.