Polythiophenes, properties mechanical

Coated materials are evaluated in S-SBR and in 50 50 blends of S-SBR and EPDM rubbers. In blends, the partitioning of fillers and curatives over the phases depends on differences in surface polarity. In S-SBR, polythiophene-modified silica has a strong positive effect on the mechanical properties because of a synergistic reaction of the sulfur-moieties in the polythiophene coating with the sulfur cure system. In S-SBR/EPDM blends, a coating of polyacetylene is most effective because of the chemical similarity of polyacetylene with EPDM. The effect of... 

Composites of polypyrrole and poly(vinyl chloride) have been prepared by several groups (64-67). Polythiophene-poly(vinyl chloride) composites have also been prepared (68). The electropolymerization of pyrrole on poly(vinyl chloride)-coated electrodes yielded composites with mechanical properties (tensile strength, percent elongation at break, percent elongation at yield) similar to poly(vinyl chloride) (65) but with a conductivity of 5-50 S/cm, which is only slightly inferior to polypyrrole (30-60 S/cm) prepared under similar conditions. In addition, the environmental stability was enhanced. Morphological studies (69) showed that the polypyrrole was not uniformly distributed in the film and had polypyrrole-rich layers next to the electrode. Similarly, poly(vinyl alcohol) (70) poly[(vinylidine chloride)-co-(trifluoroethylene)] (69) and brominated poly(vinyl carbazole) (71) have been used as the matrix polymers. The chemical polymerization of pyrrole in a poly(vinyl alcohol) matrix by ferric chloride and potassium ferricyanide also yielded conducting composites with conductivities of 10 S/cm (72-74). 

Mechanical properties of poly(thiophene-2,5-diyl) are not suitable for many practical uses. Polymers with higher flexibility and still good thermal resistance or with other special conductivity properties (after doping) can be obtained from the polymerization of substituted polythiophenes. Some examples are shown below ... 

As with polyanilines, polythiophenes can either be prepared directly by electropolymerization, or by casting from solutions (for alkyl-substituted thiophenes). Most interest has focused on the latter because of their improved mechanical properties compared with those of electrochemically prepared films. The factors influencing the mechanical properties of PTh s are reviewed in this section. 

A polythiophene anode in an aqueous electrolytic system, showed irreversible changes at a potential beyond 0.9 V on repeated reduction, suggesting that the breakdown into lower oligomers occurs, as evident from its Raman spectra [268]. However, the loss of electroactivity, electrical conductivity, electrochromic properties, mechanical properties, compact morphology... 

The electropolymerization of thiophene monomers and the quality of the resulting polymer can be strongly influenced by the nature of the substituent grafted in the [ -position. The substitution of thiophene in the P-position may be of interest for several reasons (i) the electropolymerization can be more regioselective, (ii) introduction of electron-rich substituents decreases the oxidation potential of the monomer and (iii) the presence of substituents such as alkyl chains might improve the mechanical properties of the resulting polythiophenes. 

If the electrochemical instrumental conditions are considered, the most homogeneous and conducting films are obtained under galvanostatic control [147,148, 155]. Higher quality films are formed by carrying out the polymerization at low current densities. Also, the mechanical properties of polythiophenes are affected by the electrical working conditions [156,157]. 

Yue D, Liu Y, Shen Z, Zhang L (2006) Smdy on preparation and properties of carbon nanotubes/ mbber composites. J Mater Sei 41(8) 2541-2544 Yulong D, Hajar A, Dongsheng W, Richard AW (2006) Heat transfer of aqueous susperrsions of carbon nanotubes (CNT nanofluids). Int J Heat Mass Transf 49(2) 240-250 Zaminpayma E (2014) Molecular dynamics simulation of mechanical properties and interaction energy of polythiophene/polyethylene/poly(p-phenylenevinylene) and CNTs composites. Polym Compos... 

Another widely used approach is the in situ polymerization of an intractable polymer such as polypyrrole onto a polymer matrix with some degree of processibil-ity. Bjorklund [30] reported the formation of polypyrrole on methylcellulose and studied the kinetics of the in situ polymerization. Likewise, Gregory et al. [31] reported that conductive fabrics can be prepared by the in situ polymerization of either pyrrole or aniline onto textile substrates. The fabrics obtained by this process maintain the mechanical properties of the substrate and have reasonable surface conductivities. In situ polymerization of acetylene within swollen matrices such as polyethylene, polybutadiene, block copolymers of styrene and diene, and ethylene-propylene-diene terpolymers have also been investigated [32,33]. For example, when a stretched polyacetylene-polybutadiene composite prepared by this approach was iodine-doped, it had a conductivity of around 575 S/cm and excellent environmental stability due to the encapsulation of the ICP [34]. Likewise, composites of polypyrrole and polythiophene prepared by in situ polymerization in matrices such as poly(vinyl chloride), poly(vinyl alcohol), poly(vinylidine chloride-( o-trifluoroethylene), and brominated poly(vi-nyl carbazole) have also been reported. The conductivity of these composites can reach up to 60 S/cm when they are doped with appropriate species [10]. 

The parameters affecting the formation of important CEPs, such as polypyrroles, polyanilines and polythiophenes are discussed. How these parameters can be used to manipulate the chemical, physical and mechanical properties of fhese polymers is then revealed. We attempt to clarify the chemical and energy parameters that determine the structure and, hence, the chemical, electrical and mechanical properties of fhese fascinating structures. We present some examples wherein the ability to manipulate the structure and properties of conducfing polymers is used fo produce materials with useful sensing, processing and acfuafing properties. 

Mechanical Properties of Polythiophenes Chemical properties Switching properties Optical properties of polythiophenes... 

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