Showing papers in "European Polymer Journal in 1974"

TL;DR: In this article, a model for the crystal and molecular structure of poly(p-phenylene terephthalamide) was proposed based on an X-ray diffraction study.

TL;DR: In this paper, the radius of gyration and persistence length of polymer molecules in bulk atactic polystyrene have been measured by means of low angle neutron scattering and the results support the model of an unperturbed Gaussian coil for this polymer.

TL;DR: In this paper, the melting point of polymers is measured by plotting the melting peak temperatures as a function of the square root of heating rate and linear extrapolation to zero heating rate.

TL;DR: In this article, three different kinds of u.v. oxidative behavior were observed in polyethylene, typical of the efficient triplet activators such as benzophenone and its derivatives, causing an initial rapid oxidation, increasing with ketone concentration, followed by auto-retardation.

TL;DR: In this paper, the authors derived an equation which allows determination of the classical efficiency of initiation as a function of [I]/[M]2 and also allowed a correction of Rp in handling the above equation by taking into account the small amount of monomer consumed in initiation.

TL;DR: In this article, a plausible mechanism was formulated for the photo-oxidation of polybutadiene, consistent with all the observed physical and chemical changes, and both photo-and thermal oxidative polymer degradation initially result in the formation of α, β-unsaturated carbonyls which, under photodegrading conditions, are subsequently photolysed to yield the observed final products.

TL;DR: The conformation of a copolymer of vinyl pyrrolidone and allylamine adsorbed at the silica-solution interface has been studied by EPR spectroscopy as discussed by the authors.

TL;DR: In this article, an orthorhombic unit-cell has been proposed to account for the observed reflections, the cell constants are: a = 21·48 ± 0·02 A ; b = 11·55 ± 0.03 A ; c = 7·096 ± 0 ·003 A.

TL;DR: In this paper, the results of viscosity and light scattering measurements on fractions of poly[N-(2-hydroxypropyl)methacrylamide] in several solvents were used for the determination of the parameters of the Mark-Houwink equation, characteristic ratio and its temperature coefficient.

TL;DR: An apparatus for measuring the time dependence of light scattering intensity (LSI) in the μsec range was developed in this paper, where the degradation of polyphenylvinylketone (PPVK) in benzene solution and that of polymethylmethacrylate (PMMA) in acetone solution were investigated at room temperature.

TL;DR: In this article, the authors investigated the crosslinking copolymerization of N-(2-hydroxypropyl)methacrylamide with ethylene-bismethacetyl-acrylonitrile or methylene-bisacryamide.

TL;DR: Water-soluble Cu(II) complexes of poly-4-vinylpyridine, partially quaternized by methyl bromide or dimethylsulphate (PP, Mt) were studied by physicochemical technique such as visible spectrophotometry, viscosity, speed sedimentation and EPR spectroscopy as discussed by the authors.

TL;DR: The rotational activation energy was ∼ 2 kJ/mole below T g and ∼ 10 kJ /mole above T g in polyethylene glycol samples of mol as discussed by the authors.

TL;DR: In this article, a good agreement between the results of various methods for determination of compatibility was established for various methods involving dielectric and physico-mechanical properties and also thermal analysis.

TL;DR: In this article, the second-order constants of the nucleophilic reaction for copolymers of poly-4-vinylpyridine and poly-phenacylbromide (PPyKt) were determined at various pH values in water at 25°.

TL;DR: The kinetic parameters of the complex reaction between phenol and formaldehyde in the presence of sodium hydroxide (NaOH) have been obtained by differential scanning calorimetry (DSC).

TL;DR: In this paper, the authors investigated the kinetics of anionic polymerization of methylmethacrylate in tetrahydrofuran at −75 and showed that the polymerization proceeds practically without side reactions under these conditions.

TL;DR: In this article, the effect of fractional composition on the rheological (flow and elastic) properties of a system, using mixtures of polybutadienes with narrow molecularweight distribution (MWD), was investigated.

TL;DR: In this paper, the second-order rate of NPA hydrolysis was independent of the length of alkyl groups and the salt concentration in aqueous solution, while an increase of the degree of quaternization (β) for PVP derivatives resulted in a reduction of the value of Ki in water, in 37-50 vol per cent alcohol-water there was the opposite effect.

TL;DR: In this paper, the degradation of copolymers has been studied using thermogravimetry and thermal volatilization analysis; product analysis has been carried out by GLC and spectroscopy.

TL;DR: In this paper, a conclusion is drawn on chain character of cyclo-olefin ring-opening polymerization from experimental data, and it was suggested that the active centres of this process are carbene complexes of transition metals (W, Mo, Re).

TL;DR: In this article, the fluorescence spectra of amorphous atactic, isotactic and crystallized isotactic polystyrene films have been compared and the effect of chain orientation has also been analysed on amorphized atactic samples.

TL;DR: In this article, the effect of copolymerization on the structural order of poly(p-biphenyl acrylate) has also been given preliminary study, and copolymers of any composition display morphological order in the solid state.

TL;DR: In this article, the heat of formation ΔH of the stereocomplex of iso + syndiotactic poly(methyl methacrylate) in a 1 per cent solution in dimethylformamide and in toluene was measured.

TL;DR: In this paper, it was shown that antioxidants previously reported to be u.v. stabilizers can be distinguished by their mode of action into two categories: melt stabilizers, which destroy hydroperoxides during the processing operation, and U.V. exposure.

TL;DR: In this paper, the energy levels of the triplet states of some macrocarbonyl molecules formed in the photo-oxidation of commercial polybutadiene (48% trans, 42% cis and 10% vinyl) have been determined.

TL;DR: In this article, ten copolymers of butadiene and acrylonitrile have been prepared covering the composition range 100-25 mole %butadiene; reactivity ratios are r butadienes = 0−50, r acylindricitrile = 0 −07, and the thermal analysis techniques (TVA, TGA and DSC) have been applied to determine the general features of the thermal degradation of these copolymer.

TL;DR: The surface grafted antioxidants are also found to be effective u.v. stabilizers for polypropylene in contrast to the normal ineffectiveness of chain terminating antioxidants incorporated into the polymer by conventional techniques as discussed by the authors.

TL;DR: For a purified sample of poly(vinyl chloride, it was found that radiation of wavelength less than 300 nm causes dehydrochlorination as discussed by the authors, and that polychromatic radiation yields a constant ratio of concentrations of polyenes even from the very early stages of reaction.

TL;DR: The reaction product of an incompletely desolvated ethereal Grignard reagent and TiCl 4, when employed with a trialkylaluminium cocatalyst, possesses catalytic activity for the polymerization of ethylene, of some two orders of magnitude (on the basis of Ti) greater than that of traditional TiCl 3 catalysts as mentioned in this paper.