Showing papers on "Polystyrene published in 1983"
389 citations
186 citations
TL;DR: In this article, the morphology of PBA core-shell latex particles was investigated as a function of the addition method of styrene (St), and the thin layer chromatography/flame ionization detector (TLC-FID) technique was used to characterize the morphology.
Abstract: The morphology of polybutylacrylate–polystyrene (PBA–PS) core-shell latex particles prepared by seeded emulsion polymerization was investigated as a function of the addition method of styrene (St). The thin layer chromatography/flame ionization detector (TLC–FID) technique was used to characterize the morphology of the core-shell latexes. It was found that grafting PS to the PBA core occurs during seeded emulsion polymerization. The percentage of grafting depended on the method of addition of St, being greatest for the batch reaction, less for the preswollen batch reaction, and least for the semibatch reaction. Upon aging the PBA core-polymer migrated out of the latex particles with a low degree of grafting to form dumbellshaped particles, whereas the PBA–PS core-shell particles with a high degree of grafting remained spherical because of the emulsifying ability of graft copolymer.
119 citations
TL;DR: In this article, the glass transition temperature of polystyrene has been studied by DSC Glass transition, well known for macromolecules, has been observed up to the monomer.
Abstract: Glass transition temperature of polystyrene has been studied by DSC Glass transition, well known for macromolecules, has been observed up to the monomer Measurements of the change in heat capacity ΔCp at Tg were carried out and a relationship between \(\frac{{\Delta Cp}}{T}\) and \(\overline {Dp}\) has been found The results have been interpreted as a modification of interaction occuring at \(\overline {Dp}\)≃25
102 citations
TL;DR: In this paper, self-diffusion coefficients were found to be proportional to M−2.0±0.1w above and below the critical molecular weight Mc. The influence of internal field gradients, which have previously been reported for polyethylene melts, is demonstrated and discussed.
100 citations
TL;DR: In this article, a nouvelle synthese d'acide seleninique lie a un support polystyrene and a triphasique polymere and d'hydroperoxyde de t-butyle dans CHCl 3 a reflux realise l'oxydation selective d'alcools benzyliques en especes carbonylees.
Abstract: On decrit une nouvelle synthese d'acide seleninique lie a un support polystyrene. Un systeme triphasique du polymere (en quantites catalytiques) de H 2 O 2 aqueuse et de CH 2 Cl 2 est un bon milieu de conversion des olefines en trans diols et des cetones en esters. Un systeme biphasique du polymere et d'hydroperoxyde de t-butyle dans CHCl 3 a reflux realise l'oxydation selective d'alcools benzyliques en especes carbonylees
86 citations
TL;DR: In this article, the authors cast polystyrene or polymethyl methacrylate on oxidized silicon substrates, then detached by the application of gas or water pressure from the back side of the film through a hole in the substrate.
Abstract: Films of polystyrene or polymethyl methacrylate were cast on oxidized silicon substrates, then detached by the application of gas or water pressure from the back side of the film through a hole in the substrate. Critical detachment pressures showed good repeatability and could be used to calculate the work of adhesion. For polystyrene on a hydrophilic silica in the presence of water, the apparent work of adhesion is 78 mJ/m2. Other polymer/ substrate combinations gave meaningful variations in detachment pressure.
83 citations
TL;DR: In this paper, a number of samples of poly(D,L-lactic acid) (PLA) with weight-average molecular weights in the range 15,000-350,000 were prepared by a ring-opening polymerization.
Abstract: A number of samples of poly(D,L-lactic acid) (PLA) with weight-average molecular weights Ṁw in the range 15,000-350,000 were prepared by a ring-opening polymerization. The molecular weight distributions (MWDs) of these samples were determined by gel permeation chromatography (GPC). The method involves a universal calibration of the columns on the basis of polystyrene standards and a rapid iteration algorithm leading to the establishment of the Mark-Houwink relationship. In addition, osmometry and viscometry data are presented. The effect of hydrolytic degradation on the MWD of two PLA samples was studied by GPC.
79 citations
74 citations
TL;DR: The glass transition temperatures (Tg) have been measured for blends of polystyrene and poly(α-methyl styrene) in the molecular weight ranges: poly styrene, 2030 as mentioned in this paper.
74 citations
TL;DR: Preparation des melanges en faisant varier la composition, le solvant et l'histoire thermique as mentioned in this paper, and le solvé et le solver.
Abstract: Preparation des melanges en faisant varier la composition, le solvant et l'histoire thermique
TL;DR: In this paper, a method has been developed to synthesize cyclic polystyrene molecules, by reacting bifunctional living poly styrene with α,α′ dibromo-p -xylene.
TL;DR: In this paper, the extent to which flow in a miscible polymer blend can displace the phase separation temperature is investigated. But the results were limited to the case of polystyrene/poly (vinyl methyl ether) in the temperature ranges where it undergoes exsolution.
Abstract: Results indicating the extent to which flow in a miscible polymer blend can displace the phase separation temperature are reported. Data were obtained on the system, polystyrene/poly (vinyl methyl ether), in the temperature ranges where it undergoes exsolution upon heating. The theoretical framework for the observed flow‐induced miscibility is described.
TL;DR: In this paper, an ESCA investigation has been made of the changes in surface functionalization for a series of polymers effected by means of low-powered inductively coupled rf plasmas excited in hydrogen and oxygen.
Abstract: An ESCA investigation has been made of the changes in surface functionalization for a series of polymers effected by means of low-powered inductively coupled rf plasmas excited in hydrogen and oxygen. Reactions in each case are confined to the outermost surfaces of the polymer films and the use of oxygen plasmas leads to extensive oxidative functionalization. Bisphenol-A polycarbonate and polyethylene terephthalate exhibit similar overall reactivities to both oxygen and hydrogen plasmas, while polystyrene is shown to be substantially more reactive than high-density polyethylene to the plasma treatments of interest in this work. Comparison has been made of the effects of straight hydrogen and oxygen plasmas and of sequential hydrogen/oxygen and oxygen/hydrogen plasma treatments.
TL;DR: In this paper, the authors used the Couchman-Karasz treatment to predict the depression of glass transition temperature in polystyrene and styrene/divinylbenzene networks.
Abstract: The depression of glass transition temperature in polystyrene and styrene/divinylbenzene networks, by the addition of ethylbenzene, ethyl acetate, and m-diethylbenzene, respectively, has been investigated by differential scanning calorimetry. The predictive quality of the Couchman–Karasz treatment for the composition dependence of Tg in compatible systems was found to provide excellent agreement with experimental results for the depression of Tg by ethylbenzene, provided certain modifications were made. Qualitatively, the theory predicts that for a given diluent, the depression of Tg is particularly sensitive to the incremental change in heat capacity of the pure polymer or network. The behavior of ethylbenzene provided good quantitative agreement with the theory, provided that the incremental change in heat capacity of the diluent at its Tg was approximated by ΔCp = constant/T and that the incremental change in heat capacity of the network at Tg represents only those units capable of thermal activation. The anomalous behavior observed on plasticization by ethyl acetate and m-diethylbenzene could in part be explained by a reduction in solvent quality or syneresis of diluent in the highly crosslinked samples.
TL;DR: In this paper, a reaction de derives organometalliques de metal alcalin reactifs du polystyrene reticule avec des solutions de dichloro (cyclooctadiene-1,5) palladium (II) pour former des catalyseurs palladium/polystyrene.
Abstract: Reaction de derives organometalliques de metal alcalin reactifs du polystyrene reticule avec des solutions de dichloro (cyclooctadiene-1,5) palladium (II) pour former des catalyseurs palladium/polystyrene. Caracterisation par ESCA et microscopie electronique, et activite comme catalyseurs d'hydrogenation
TL;DR: In this paper, a study was made on the application of normal phase liquid chromatography for the separation of aromatic and polar compounds in fossil fuel liquids, and several commercially available packings including chemically bonded phases (NO/sub 2/, NH/sub2/,CN, and sulfonic acid), silica, alumina, and porous polystyrene gel were compared for the extraction of aromatic compounds by ring number, separation of polar compounds (nitrogen and oxygen-containing compounds) from polynuclear aromatic hydrocarbons and the resolution between polar compounds by functional group.
Abstract: A study was made on the application of normal-phase liquid chromatography for the separation of aromatic and polar compounds in fossil fuel liquids. Several commercially available packings including chemically bonded phases (NO/sub 2/, NH/sub 2/,CN, and sulfonic acid), silica, alumina, and porous polystyrene gel were compared for the separation of aromatic compounds by ring number, separation of polar compounds (nitrogen- and oxygen-containing compounds) from polynuclear aromatic hydrocarbons and the resolution between polar compounds by functional group. Model compounds expected to be present in these liquids were used for the evaluation of the packings. In the case of fuel liquid samples, the chromatographic behavior of each compound class varied according to their source and boiling range. 3 figures, 4 tables.
TL;DR: In this paper, a sharp crossover was observed in the variation of the reduced viscosity ηsp/c as a function of the concentration c for mixtures of polystyrene and poly(methylmethacrylate) in benzene at 20°C.
Abstract: A very sharp crossover is observed in the variation of the reduced viscosity ηsp/c as a function of the concentration c for mixtures of 1:1 by weight mixtures of polystyrene and poly(methylmethacrylate) in benzene at 20°C and a 1:1 by weight mixture of poly(ethylene glycol) and polystyrene in benzene at 20°C. The crossover is attributed to the critical to the concentration of the two respective polymers in the solution and its sharpness is due to the incompatibility between the two different polymers.
Patent•
10 May 1983TL;DR: A polystyrene foamed sheet suitable for thermoforming and containers such as cups or trays formed therefrom is defined in this paper, which is a sheet consisting of a poly styrene resin as the base resin which contains a specific quantity of each a rubber component and a filler, having specific bulk density, thickness, stretch ratio and residual gas quantity.
Abstract: A polystyrene foamed sheet suitable for thermoforming and containers such as cups or trays formed therefrom, the foamed sheet comprising a polystyrene resin as the base resin which contains a specific quantity of each a rubber component and a filler, having specific bulk density, thickness, stretch ratio and residual gas quantity, and said sheet being preferably laminated with a film.
TL;DR: In this paper, the photodegradation of polystyrene has been studied by electron spin resonance, infra-red absorption, viscosity and gel fraction measurements, and the degradation reaction was found to proceed via peroxide intermediates and result in main-chain scission leading to the formation of carbonyl compounds.
TL;DR: In this paper, the properties of three-block copolymers poly[styrene-b-(ethene-co-butene)-b-styrene, where the middle aliphatic block amounts to about 70 wt.-%, were determined by combining the results of light scattering, small-angle X-ray scattering, photon correlation spectroscopy, osmometry, and viscometry.
Abstract: Three-block copolymers poly[styrene-b-(ethene-co-butene)-b-styrene], where the middle aliphatic block amounts to about 70 wt.-%, form micelles in 1,4-dioxane with an aliphatic core and a polystyrene shell. The basic characteristics concerning the ratio unimer/micelles, the micellar molar mass, the radius of gyration, and the hydrodynamic radius were determined by combining the results of light scattering, small-angle X-ray scattering, photon correlation spectroscopy, osmometry, and viscometry. The characteristics of the micelles, approximated by the model of concentric spheres, were calculated from the data of light scattering and small-angle X-ray scattering. From a comparison of the geometric and hydrodynamic dimensions of the micelles it follows that in dilute solutions they behave like rigid spheres.
TL;DR: Pulse radiolysis studies on pure carbon tetrachloride, pure chloroform, and their solutions containing polystyrene and benzene, and on poly styrene in cyclohexane solutions were carried out by using the pico-and nanosecond Pulse Radiolysis system as discussed by the authors.
TL;DR: In this paper, a series of graft copolymers of crosslinked polydimethylsiloxane (PDMS) containing up to 56.3% polystyrene (PS) and for a block copolymer of PDMS and PS containing 28 mole % PS were studied.