No abstract

No abstract

No abstract

In this study, the synthesis of polypyrrole‐b‐vinyl aniline modified cyclohexanone formaldehyde resin (PPy‐b‐CFVAnR) block copolymers by a combination of condensation polymerization and chemical oxidative polymerization processes was examined. First, a cyclohexanone formaldehyde resin containing vinyl aniline units [4‐ vinyl aniline modified cyclşohexanone formaldehyde resin (CFVAnR)] was prepared by a direct condensation reaction of 4‐vinyl aniline and cyclohexanone with formaldehyde in an in situ modification reaction. CFVAnR and pyrrole (Py) were then used with a conventional method of in situ chemical oxidative polymerization. The reactions were carried out with heat‐activated potassium persulfate salt in the presence of p‐toluene sulfonic acid in a dimethyl sulfoxide–water binary solvent system; this led to the formation of desired block copolymers. The effects of the oxidant–monomer molar ratio, dopant existence, addition order of the reactants, and reaction temperature on the yield, conductivity, and morphology of the resulting products were investigated. PPy‐b‐CFVAnR copolymers prepared with a resin‐to‐Py molar ratio of 1:40 showed conductivity in the range 3.7 × 10−1 to 3.8 × 10−2 S/cm. Oxidant‐to‐Py molar ratios of 0.5 and 1.0 were proposed to be the optimum stoichiometries for higher conductivity and yield, respectively, of the copolymer. The morphology of the copolymer (PPy‐b‐CFVAnR) was investigated with environmental scanning electron microscopy analyses. The results indicate that the surface of the copolymer was composed of well‐distributed nanospheres with average particle diameters of 60–85 nm. Also, the synthesized PPy‐b‐CFVAnR had a higher thermal stability than the pure CFVAnR. The chemical composition and structure of the PPy‐b‐CFVAnR copolymers were characterized by Fourier transform infrared spectroscopy and measurement. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 132, 42841.

Purpose This paper aims to synthesise block copolymers (PPy-b-ENP) of pyrrole (Py) and ethoxylated nonyl phenols (ENP) via redox systems in presence of ceric ammonium nitrate (CAN) at room temperature. The initiating radical was formed on reducing organic compound which in turn initiated polymerisation to give diblock copolymers containing chain ends of ENPs and polypyrrole (Ppy). The effects of the concentration of Ce+4 salt, ENPs and Py on both the yield and electrical conductivities of corresponding polymers were studied. Design/methodology/approach In total, 0.1 M stock solution of CAN:100 ml 1 M HNO3 was prepared freshly (7 ml HNO3 dissolved in 100 ml water) and used in 50 ml of 0.1 M CAN solution (2.7438 g CAN dissolved in 50 ml nitric acid solution). The reducing compound (Py) was dissolved in water. Py and ENP were added slowly to the flask with vigorous stirring. The content of the flask was flushed with oxygen-free nitrogen. The resulting copolymers were characterised with spectroscopic methods like Fourier transform infrared spectroscopy and scanning electron microscope. Findings In this study, DMSO-slightly soluble Py copolymers were produced with ENPs. The conductivities of copolymers were found to be in the range of 10-1 to 10-4 S/cm. Soluble and processable conductive polymers were developed. Research limitations/implications In this study, the water solubility of ENPs diminishes the conductivity of copolymer because of its surfactant structure. When the CAN/Py ratio was increased, PPys and copolymers with both higher yield and lower conductivity values were obtained. The results indicated that solubilities and the yield of the polymers synthesised in the presence of ENP have increased considerably. ENP caused degradative chain transfer reaction to become significant compared with bimolecular termination, so the yield decreased with increasing ENP concentration about 20 g/l. Results showed that yield of the copolymers strongly depends on Ce+4 concentrations while of copolymers were measured to be 10-3 S/cm. Practical implications PPy-b-ENP diblock copolymers were prepared with Ce+4 as an oxidation agent in a single step. Social implications These slightly soluble and conductive copolymers may overcome difficulties in the applications of PPy homopolymers and open new application areas. Originality/value PPy-b-ENPs of lightly soluble (in DMSO) and conductive (10-2 S/cm) copolymers have been synthesised in one step. The results indicate that the surface of the copolymer is composed of well-distributed nanospheres with an average particle diameter of 35-400 nm.