Electrochemical preparation and characterization of carbon fiber reinforced poly (dimethyl siloxane)/polythiophene composites: electrical, thermal and mechanical properties

A series of polydimethylsiloxane (PDMS)/polythiophene (Pth)/carbon fiber (CF) composites was synthesized by electrochemical polymerization using tetrabutylammoniumtetrafluoroborate (TBAFB) as supporting electrolyte and acetonitrile as solvent. Composites were characterized by TGA, SEM, and mechanical tests and conductivity measurements. Conductivities of composites were in the range of 25 S/cm. SEM studies show that CF were coated by PDMS/Pth matrix and well oriented in the matrix. In mechanical tests it has been observed that higher percent elongation was obtained by increasing PDMS content whereas tensile strength and modulus of composites increases with increasing CF content

Synthesis and characterization of poly(dimethylsiloxane)-polythiophene composites

The synthesis was performed by the electropolymerization of thiophene on a poly(dimethylsiloxane) (PDMS)-coated platinum electrode at 2.2 V with tetrabutylammoniumtetrafloroborate (TBAFB) as a supporting electrolyte and with acetonitrile as a solvent. The characterization of the PDMS-polythiophene (Pth) composites was carried out with cyclic voltammetry, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis, and conductivity measurements. The observed conductivities of the PDMS composites were 2.2-5.2 S/cm. The conductivity of Pth did not change appreciably with the addition of up to 30% insulating PDMS, but its processability improved. FTIR, SEM, and DSC studies showed the existence of a strong interaction, rather than physical adhesion, between PDMS and Pth. Highly flexible and foldable PDMS-Pth composites were obtained. (C) 2003 Wiley Periodicals, Inc

ANIONIC SYNTHESIS AND CHARACTERIZATION OF POLY(4-VINYLPYRIDINE)-POLY(DIMETHYLSILOXANE) BLOCK COPOLYMERS

Poly(4-vinylpyridine)-b-Poly(dimethylsiloxane) (P4VP-b-PDMS) copolymers have been synthesized by sequential anionic polymerization of 4VP and hexamethylcyclotrisiloxane at - 70-degrees-C. The initiator was sodium naphthenate. The solvent used during reactions has a very critical role in an homogeneous polymerization medium. A 1:1 pyridine/THF mixture was found to be the most suitable. The products were characterized by H-1-NMR spectroscopy, transmission electron microscopy (TEM) and differential scanning calorimetry (DSC) techniques. All the results indicated the formation of 4-vinylpyridine-siloxane block copolymers. Also, the P4VP blocks can be completely quaternized with methyl iodide as indicated by H-1-NMR and FTIR spectroscopies

Flexible and conducting composites of polypyrrole and polydimethylsiloxane

Conductive and flexible polydimethylsiloxane (PDMS)/polypyrrole (PPy) composites were synthesized electrochemically. Electrochemical syntheses were performed at +1.10 V by using p-toluene sulfonic acid (PTSA) as supporting electrolyte and water as solvent. Composites were characterized by cyclic voltammetry, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, and Fourier transform infrared spectroscopy. Conductivity measurements and mechanical tests were also performed. The observed conductivities were in the range of 3.5-7.6 S/cm, indicating that the conductivities of PDMS/PPy composites and that of pure PPy were in the same order of magnitude. Tensile tests revealed that higher percent elongation was obtained by the addition of PDMS. Highly flexible and foldable PDMS/PPy composites were successfully synthesized, which have high conductivities and unproved mechanical properties. (C) 2004 Wiley Periodicals, Inc

SOLUTION PROPERTIES AND CHAIN STIFFNESS OF POLY(ACENAPHTHYLENE)

Solution properties of poly(acenaphthylene) (PACN) were investigated in a theta solvent (1,2-dichloroethane) and a good solvent (chloroform). The viscosity exponent alpha was found to be 0.50 at both 35 and 41-degrees-C in 1,2-dichloroethane. Unperturbed dimensions found from viscometric measurements were compared with those of other vinyl aromatic polymers. Calculation of the chain flexibility parameters led to the conclusion that PACN is a rather stiff chain compared to other vinyl polymers with its characteristic ratio C(infinity) of 18.2 and chain flexibility parameter lambda of 7

Synthesis, characterization and electrical conductivity of poly(p-phenylene vinylene)

Poly (p-phenylene vinylene) (PPV) was prepared electrochemically from p-xylene-bis (diethylsulphonium chloride) in a solvent-electrolyte couple of acetonitrile-tetrabutylammonium tetrafluoroborate (TBAFB). The polymer obtained from the electrode surface was converted to PPV by the thermal elimination of diethyl sulfide, HCl and ethyl sulfide. PPV was also obtained chemically in order to investigate the effect of the synthetic method on the structure and electrical conductivity. The characterization of the polymers was carried out by means of fourier transform infrared spectrometer (FTIR), differential scanning calorimetry (DSC) and thermal gravimetry analysis (TGA) techniques. The doping effect on the conductivity of the PPV was investigated by using different agents such as H2SO4, I-2 and metallic Na

Electrically conductive polymers from poly(N-vinylimidazole)

Poly(N-vinylimidazole) was synthesized by free radical polymerization. It was quaternized with methyl iodide. The samples were doped with iodine and borontrifluoride. Products were characterized by elemental analysis, Fourier transform infra-red spectroscopy and differential scanning calorimetry techniques. The maximum electrical conductivities achieved were 10(-4) S cm(-1) for BF3-doped and for I-2-doped QPVI. The decrease of electrical conductivity in open atmosphere with time was also studied to understand the stability of doped polymers. Temperature dependence of electrical conductivity exhibits a semiconductor behaviour. Copyright (C) 1996 Elsevier Science Ltd

CONDUCTIVE PROPERTIES OF POLY(4-VINYLPYRIDINE) POLY(DIMETHYLSILOXANE) BLOCK-COPOLYMERS DOPED WITH TETRACYANOQUINODIMETHANE

Poly(4-vinylpyridine)-poly(dimethylsiloxane) (P4VP-PDMS) block copolymers with various compositions were prepared by anionic polymerization. The 4VP block was quaternized with methyl iodide and reacted with 7,7',8,8'-tetracyanoquinodimethane (TCNQ), which is in both anion radical (TCNQ-.) and neutral form (TCNQ0). The products were then characterized by H-1 nuclear magnetic resonance and Fourier-transform infra-red spectroscopy, scanning electron microscopy and differential scanning calorimetry techniques. The electrical conductivities of processable and flexible films of these block copolymers were measured with the four-probe method and found to be as high as 10(-2) S cm-1. The optimal TCNQ0 doping for which the conductivities are highest were also determined