Study On Preparation And Properties Of Polypyrrole Nanosphere And Polypyrrole/Polymers Conductive Composite

Polypyrrole (PPy), as a kind of conductive polymer, has conductivity reaching thelevel of some semiconductors. Meanwhile, PPy has good chemical stability andbiocompatibility. As a result, PPy has broad application prospects in field ofbiomaterials and tissue engineering，particularly in areas of neural tissue engineering.The morphology and microstructure of PPy had great influence on the properties of PPy.In this work, effects of the type and concentration of oxidants and template agents,and the reaction temperature on the morphology and electrical conductivity of PPy werestudied. P123, a kind of block copolymer which can assemble into micelles in aqueoussolution, acted as the template agent to regulate the morphology of the product.Spherical PPy nanoparticles with good dispersion were obtained when P123was present.The mean diameter of PPy particles decreased as the concentration of P123increased.The conductivity of PPy was obviously increased by the addition of P123duringsynthesis. The conductivity of obtained PPy using ferric chloride as oxidant was greaterthan that using ammonium persulfate as oxidant. The molar ratio of ferric chloride topyrrole monomer and reaction temperature would also influence on morphology andsize of the product.The sol of hyaluronic acid (HA) was mixed with PPy by magnetic stirring. It wasfound that the addition of PPy improved the conductivity of the sol, but could not makepercolation happen. HA/PPy sol was crosslinked with EDC, ADH to improve themechanical properties of HA/PPy gel. HA was also mixed with sodium alginate toincrease the rate of crosslink reaction of the HA/PPy gel. However, the mechanicalproperties of the gel were still insufficient to the requirements of rapid prototyping.PLA/PPy and PLA/PHA/PPy composite films were obtained by solution casting.Two different kinds of nano-particles of PPy were used in this research, which werenanosphere and nanowire. Nanosphere was obtained by the synthesis of PPy in whichferric chloride was oxidant and P123was template agent, while nanowire PPy wasobtained when methyl orange (MO)-ferric chloride acted as both oxidant and templateagent. PPy nanospheres and nanowires were mixed with PLA respectively. Percolationwas found in both kinds of PLA/PPy composite. However, the curve ofconductivity-ingredient of PLA/PPy was different when the shape of PPy changed from nanowire to nanosphere. It reflected the difference of the PPy particles in shape wouldinfluence on the percolation behavior of PLA/PPy composite. Research also showedthat addition of PHA increased the conductivity of PLA/PPy composite and changed theshape of conductivity-ingredient curve.