Showing papers in "European Polymer Journal in 1975"

TL;DR: In this article, it was shown that during the processing of low density polyethylene, the hydroperoxide content increases rapidly to a very sharp maximum and then declines, and that the rate of destruction is related to the level of carbonyl concentration.

TL;DR: The glass transition temperatures for a number of oligomers and polymers have been measured as a function of chain length as mentioned in this paper, and it has been shown that a plot of Tg against log x (where x is the number of chain segments) can be divided into three distinct regions.

TL;DR: In this article, a method is proposed for analysing the problems associated with non-ideal polymerizations reflected mainly in the variability of Rp/[I]0·5[M] where Rp is the rate of polymerization and [I] and [M] are the initiator and monomer concentrations, respectively.

TL;DR: In this article, the photoxidative degradation of unprocessed PVC was studied by i.r. and u.v. spectroscopy and gel permeation chromatography.

TL;DR: In this paper, a viscoelastometric technique was used to study structural changes in high impact polystyrene during photo-oxidation under artificial weathering conditions, and it was found that the damping peak at −80° (corresponding to the β-transition temperature of polybutadiene) disappeared completely after irradiation for 14 hours.

TL;DR: In this paper, the reproducibility of the derived reaction parameters, their variation with scan speed and the absolute values of reaction rate constants obtained, are discussed, and the kinetic values are shown to be reasonably reliable when used to calculate extents of cure resulting from thermal curing cycles.

TL;DR: In this article, the behavior of weak unsaturated acids (such as acrylic and methacrylic) and their salts in radical polymerization in aqueous solutions was studied, and a characteristic of these reactions was attributed to change of the effective reactivity of the propagating radicals with the nature of the reaction mixture.

TL;DR: In this article, the copolymerisation de l'acrylamide avec l's acrylonitrile en solution dans different solvants is investigated.

TL;DR: In this paper, a reassessment of the dilute solution behavior of amylose acetate in nitromethane has been made, using linear fractions encompassing the low molecular weight region.

TL;DR: In this article, the formation of 3-dimethylaminopropyl-lithium from the reaction of 3chloro-1-(dethylamino)-propane with powdered lithium in tetrahydrofuran (THF) at −25° and in cyclopentane (CP) at +49·5°, respectively, has been investigated.

TL;DR: In this article, the importance of the migration of plasticizers and the basic differences due to types of contact was analyzed, and the effects of the following factors on the migration process were examined: (a) the nature of petroleum oil, (b) the characteristics of the phthalate plasticizer, (c) the amount of plasticizer; (d) the plasticization process; (e) the temperature; and (f) the time.

TL;DR: The chemical reactions involved in the antioxidant behavior of the thiodipropionate esters have been investigated and three distinct mechanisms have been identified as discussed by the authors, namely, a radical trapping process involving the sulphenic acid formed by breakdown of the sulphinyldipropianate ester which is an oxidation product of thiodiopionate.

TL;DR: In this article, the thermal degradation of linear poly-2-hydroxyethyl methacrylate and of its acetyl and methoxy derivatives was investigated by the Curie-point pyrolysis gas chromatography.

TL;DR: In this article, a method of calculating free energy of mixing of two polymers has been proposed, from a study of the sorption of organic solvents vapour by different polymers and their mixtures.

TL;DR: In this paper, the authors decrit une etude cinetique approfondie de la deshydrochloruration thermique du chloro-4-hexene-2, modele de structure allylique instable du polychlorure de vinyle.

TL;DR: In this article, a spin-labelled low density polyethylene was spin-labeled with an oxazolidine-N -oxyl group and a correlation map revealed the α- and β-relaxation processes in solid polyethylenes, with activation energies of 48 and 28 kJ mol −1, respectively.

TL;DR: In this article, the emission spectra of unstabilized polystyrene samples from various producers, as well as carefully purified laboratory polymers, have been investigated by u.v.-absorption, fluorescence, phosphorescence and i.r. spectroscopy.

TL;DR: In this paper, the preparation of polydimethylsiloxanes (PDMS) of narrow molecular weight distribution (MWD) by anionic polymerization of hexamethylcyclotrisiloxane (D 3 ) in an improved polymerization apparatus is described.

TL;DR: The possibility that the statistical structure of 1,4- cis-polyisoprene (natural rubber) could be interpreted with a statistical succession of different conformations along the polymer chain has been investigated in this paper.

TL;DR: In this paper, the authors investigated the existence of a reaction de propagation assistee dans the aggregats auto-associes de l'acide acrylique. But their conclusion was not supported by the experimental results.

TL;DR: In this paper, the influence of molecular weight on the preferential adsorption coefficient was analyzed for the ternary system: isotactic polybutene-1-cyclohexane-n -propyl alcohol.

TL;DR: In this paper, Dicyclohexyl itaconate was polymerized with AIBN as initiator, and the relation [ η ] = 13·1 × 10 −3. M 0·62 for toluene at 25° was established.

TL;DR: In this article, the authors studied the kinetics of polymerization of diethylfumarate initiated by 1,1′ azo-bis-isobutyronitrile at temperatures between 60 and 80°.

TL;DR: In the presence of ZnCl 2, le chlorure de zinc catalyse leur substitution sur le chlore allylique; le phosphonate resultant peut etre deplace par HCl s'il n'y a pas une exces de phosphite.

TL;DR: In this paper, the mean lifetime of the excited state of the anthracene group for the polymers and for the monomer analogue (F) with increasing quencher concentration and use of the Stern-Volmer relation were studied by fluorescence quenching method.

TL;DR: In this paper, the thermal degradation of polypropylene is accelerated by 2537 A radiation (photothermal degradation) and methane and ethylene appear as additional products, which are associated with photoinitiation of the radical process involved, the mechanisms of the thermal and photothermal reactions being otherwise identical.

TL;DR: In this paper, a study was made of the kinetics of oxygen absorption and isothermal weight change as a function of layer thickness for molten polyethylene at 157° under oxygen at 650 torr pressure.

TL;DR: In this article, both virgin and degraded PVC with di(butyl[35S]thiolato)dibutyltin have been examined, and it was shown that during an induction period, there is a slow incorporation of 35S into the polymer thought to be caused by exchange with allylic chlorine atoms: the amount of radioactivity retained corresponds to ~ 3 chlorine atoms per 100 polymer molecules.

TL;DR: In this article, a semi-empirical method proposed by Vedeneyev was used to study the CCl ∆C ∆H and C ∆ C bonds in polyvinyl chloride and the activation energies for elimination of hydrogen chloride were calculated on the principle of the additivity of bond energies of the four-membered activated complex.

TL;DR: In this article, the rate constants of separate steps of polymer dehydrochlorination and the dependence of concentrations of polyenes on the time of degradation were calculated and the equation has been deduced and solved to describe the thermal degradation of PVC.