Preparation And Characterization Of Polyacetylene And Polyacetylene/Carbon Nanocomposite

Conductive polymer is a class of polymers with their conductivity between that of semi-conductors and conductors, and enhancement of conductivity is realized by doping method. Polyacetylene (PA), a typtical number of conductive polymer, has attracted much interest and became a research issue due to its extremely high conductivity by doping and wide potential applications. It is considered to be ideal photoelectric material with novel optical, electronic, photoconductivity, light emission and thermochromism.Due to the particularly harsh conditions for the synthesis of PA and catalyst oxidation problem, several strategies have been employed to solve these problems. One common approach is to seek new catalysts with low sensitive to air and moisture. Herein, we design a novel Fe(naph)2 catalyst for the synthesis of PA at room temperature.A facile two-step method has been developed to synthesize Fe(naph)2 which was obtained via the metatheses and saponification reactions. The effects of reaction time, reaction temperature and the molar ratio of substrates were systematically investigated. The suitable reaction conditions are 6h, 65℃and 0.484 molar ratio of FeSO4?7H2O to sodium naphthenate (SN). Under these optimized conditions, Fe(naph)2 with 95.58% yield and 9.2% iron content was obtained. Meanwhile, the effect of catalyst concentration, reaction temperature and reaction time on the yield and conductivity of polyacetylene were also discussed. The results show that the yield and conductivity of polyacetylene is as high as 76.4% and 1.386×10-9 S·cm^-1, respectively.Despite these developments, most PA exhibits low electric conductivity. Several strategies have been employed to address these problems. One common approach is to produce composites by introducing a second monomer with good electrical properties. Among those monomers, carbon materials have received great attention because of its unique electrical and optic properties as well as extensive application in diverse areas. The PA/C composites were prepared via the mid polymerization route with the catalyst of carbon supported Fe(naph)2. The functional group, morphology, thermal properties and electrical conductivity of this composite were investigated by IR, SEM, TG-DSC and electrical resistivity measurement, respectively. The results show that this new method has the advantages of mild reaction conditions and high yields. In addition, the preparation procedure leads to the formation of PA/carbon nanotubes composite with high conductivity (629.84 S·m^-1) and good thermal stability.Based on the PA structure and electroconductive study, a mechanism was summarized. PA is both filled and doped by carbon materials, then the conductive networks in PA/C composites consists of two kinds of conductive system. One is formed by carbon materials contact, and the other is formed via conductive units connecting.