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A series of polyaniline films have been coated on electrodes by chemical and electrochemical means in order to investigate the thermal stability of the electroactivity in air and nitrogen atmospheres. Polyaniline was also synthesized chemically and cast as a membrane (thick film). It was found that the electroactivity and conductivity of the films was stable up to 150°C. Exposure to higher temperatures...
In the anionic polymerization of phenyl glycidyl ether (PGE) initiated by sodium caprolactam (NaCL) or sodium caprolactam/N-acetyl caprolactam (NaCL/AcCL), oligo(hydroxy ethers) with different structures and distributions are formed depending on the temperature and concentration of the initiating system. The progress of the reaction was followed by using epoxide titration and high-performance liquid...
The oligomerization mechanisms of several derivatives of pyrrole have been studied by quantum-mechanical methods. Different growth processes are compared from the point of view of thermodynamic stabilities to gain insight into the branching possibilities. For the simple polypyrrole, polymerization may proceed through either an α or a β carbon with equal probabilities. When an aldehyde group is...
A detailed kinetic model is developed for the polymerization of poly(phenylene oxide) (PPO). The Box complex technique is used to obtain the best-fit values of the parameters of the model (rate constants), using experimental data on the variation of the number-average chain length (μ n ) with time for one set of conditions. A sensitivity study helps to simplify this kinetic scheme. The...
The temperature-concentration phase diagram of syndiotactic polystyrene (sPS)/benzene gels establishes the existence of two compounds, C 1 and C 2 , the stoichiometries of which, expressed as benzene molecules/monomer, are 4 (C 1 ) and 1 (C 2 ). C 1 is an incongruently-melting compound as it transforms into C 2 at about the boiling point of benzene...
1-(2-Cyanoethyl)pyrrole was chemically polymerized in acetonitrile by using iron(III) perchlorate as an oxidizing agent. Poly[1-(2-cyanoethyl)pyrrole] obtained as black powder was hydrolysed with potassium hydroxide to convert cyano groups of the polymer to carboxyl groups. The hydrolysis of the cyano groups was confirmed by means of i.r. spectroscopy. The electric conductivities of these polymers...
The effect of reactive interfacial agents on the interfacial tension of nylon-6/polystyrene (PS) blends was studied. Two types of Li end-sulfonated polystyrene (e-SPS), namely (ω-SPS and α, ω-SPS) were used as the reactive interfacial agents. The interfacial tension in the melt state was measured by the breaking-thread method. As the e-SPS content was increased, the interfacial tension of the nylon-6/PS...
The synthesis of polyesters by the reaction of dicarboxylic acid salts with bis halides or bis tosylates or by the self-condensation of salts of υ-bromocarboxylic acids, has been investigated under two different types of conditions. When benzyltrimethylammonium salts and halides were reacted together in acetonitrile at ca. 82°C the results obtained were similar to those reported in the literature...
The thermal behavior of composites of polythiophene and polyamide prepared by mechanical blending and electrochemical synthesis of polythiophene onto an electrode coated with polyamide have been studied thoroughly by the pyrolysis approach under both direct and indirect pyrolysis mass spectrometric analysis conditions. It is determined that the electrolytic film has different properties from the...
Polyamides were prepared in which part or all of the hexamethylenediamine (HMD) in nylon-6,6 was replaced by its isomer, 2-methylpentamethylenediamine (MPMD). The intermediate compositions are considered random copolymers between the two homopolymers (66 and MPMD-6). The crystalline properties of these polymers were studied by differential scanning calorimetry, X-ray diffraction and optical microscopy...
The phase transition behaviour of poly(vinyl alcohol)-graft-N-isopropylacrylamide copolymer membranes has been studied by measuring their steady-state fluorescence spectra and swelling ratios. Crosslinking with glutaraldehyde increased the tensile strength of the copolymer membrane and also resulted in a considerable decrease in the swelling ratio of the membrane. Well defined thermo-control of permeation...
A series of ferroelectric liquid-crystalline polymers (FLCPs) with siloxane backbone were synthesized in this study. The dynamics of these polymers was studied by broad-band dielectric spectroscopy (10 -1 to 10 7 Hz). The collective (Goldstone and soft mode) and molecular (α, β, γ, δ relaxation) relaxation processes were observed. These FLCPs exhibited large values of spontaneous...
Novel comb copolymers were prepared by the free-radical copolymerization of acrylamide (AM) and poly(ethylene glycol) (PEG) macromonomers in aqueous solution using potassium persulfate as an initiator. The reactivity ratios of acrylamide (M 1 ) toward macromonomers (M 2 ), r 1 =K p11 K p12 , were estimated at low conversion by using ...
Micron-size reactive polymeric microspheres with active ester groups on their surfaces were prepared by the seeded copolymerization of a polymerizable surfactant bearing an active ester group, namely p-10-undecenoyloxyphenyldimethylsulfonium methylsulfate (UPDS), and various dialkyl fumarates (DRFs), using 2,2 -azobis(2-amidinopropane)dihydrochloride (AIBA) and 2,2 -azobisisobutyronitrile (AIBN)...
Infra-red (i.r.) end-group analysis is used to determine the hydroxyl and carboxyl end-group concentrations and therefore the number-average molecular weight of poly(ethylene naphthalene-2,6-dicarboxylate)(PEN) film samples in the solid state. The end-group i.r. spectrum of a sample is obtained by subtracting the i.r. spectrum of a deuterated control sample from the experimental sample i.r. spectrum...
We have prepared a series of soluble polyalkylthiophenes in which it is possible to modulate continuously the electronic properties such as the conjugation length and the energy-gap. The copolymerization of 3-butylthiophene and 3,4-dibutylthiophene units in well defined ratios leads to materials with optical properties depending on the composition of the chain. Using size exclusion chromatography...
The inherent brittleness of tetraglycidyl methylenedianiline (TGMDA) based epoxy formulations can be mitigated by the addition of carboxyl-terminated butadiene-nitrile rubbers (CTBNs) if piperidine is used as the curing agent. The problems of toxicity, reactivity and volatility associated with this reagent are overcome by using it in a latent form, as an amino alcohol or urea, after reacting...
The influence of changing the block length of the polydimethylsiloxane block on the structure/property behaviour of two poly(ether ether ketone)-polydimethylsiloxane (PEEK-PSX) multiblock copolymers and their amorphous (non-crystallizable) ketamine precursors (PEEKt-PSX) was investigated. In the precursor block copolymer form, as well as the reduced amorphous and its corresponding semicrystalline...
Coexistence of multiple lamellar thicknesses and lamellar thickness changes in poly(ether ether ketone) (PEEK) have been supported by the results obtained from investigations using differential scanning calorimetry (d.s.c.), X-ray and scanning electron microscopy. The melting behaviour, crystallization kinetics and morphology of PEEK subjected to multiple-step crystallization have been studied. ...
In the present study, the air-liquid surface and liquid-liquid interfacial activities of hydrophobically modified poly(vinyl alcohol) (PVA) solutions were investigated to determine the effects of NaCl concentration, polymer concentration, time, polymer molecular weight, polymer modification and the average length of the hydrophobic side groups. The hydrophobically modified PVA exhibit high air-liquid...
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