Showing papers on "Polystyrene published in 1982"
TL;DR: In this paper, the diffusion activation energy (E D ) of C 1 to C 6 organic vapors was determined by gravimetric sorption rate measurements on emulsion and suspension-polymerized powder samples of PVC, polystyrene, and PMMA.
279 citations
213 citations
TL;DR: A simple solid phase method for the synthesis of oligodeoxyribonucleotides has been developed using the phosphotriester approach, particularly suitable for the automation of the synthesis upon availability of an automatic synthesizer.
Abstract: A simple solid phase method for the synthesis of oligodeoxyribonucleotides has been developed using the phosphotriester approach. Mononucleotide coupling units are sequentially added to the polystyrene copolymer with 1% divinylbenzene and two kinds of oligonucleotides, d(CACGACCCCTCCACGT) and d(AACTGGTATTACTGGGCG), are synthesized in a relatively high yield. One cycle of the mononucleotide addition is about 70 minutes, and this method is particularly suitable for the automation of the synthesis upon availability of an automatic synthesizer.
174 citations
TL;DR: In this article, a comparative study of the morphology and the mechanical behavior of modified low-density polyethylene/polystyrene blends demonstrates that a tapered diblock is more efficient than a pure Diblock with the same composition and molecular weight.
Abstract: Poly(hydrogenated butadiene-b-styrene) copolymers are very effective emulsifiers for blends of polystyrene and low-density or high-density polyethylene. It is shown that the extent of improvement in mechanical properties is dependent not only on the molecular weight but also on the structure of the diblock copolymer. A comparative study of the morphology and the mechanical behavior of modified low-density polyethylene/polystyrene blends demonstrates that a tapered diblock is more efficient than a pure diblock with the same composition and molecular weight. It is assumed that the unique behavior of the tapered sample results from its particular miscibility characteristics at the blend interface. The tapered copolymer could behave essentially as a solu-bilizing agent for the homopolymers at the interface and provide a “graded” modulus responsible for the improved mechanical response of the material.
155 citations
TL;DR: The graft copolymers were prepared by several techniques such as free radical solution polymerization, by aqueous suspension polymerization which produced beads, or by emulsion reactions which yielded stable latices as discussed by the authors.
Abstract: Pure graft polymers having uniform molecular weight polystyrene side chains were prepared by free radical copolymerization of methacrylate-terminated polystyrene macromonomers (MA-CROMER) with ethyl acrylate, butyl acrylate, or other suitable monomers. The MACROMER monomer was synthesized by living anionic polymerization under conditions that led to very narrow molecular weight distributions. Very effective end capping produced a material that was highly monofunctional. The graft copolymers were prepared by several techniques such as free radical solution polymerization, by aqueous suspension polymerization which produced beads, or by emulsion reactions which yielded stable latices. Polymerizations were reproducible. High conversion of the MACROMER monomer into pure graft polymers was achieved, and the product was contaminated with only a little homopolymer. The milled and molded phase-separated graft polymers had optical clarity and physical properties characteristic of polystyrene-reinforced triblock polymers. Compositions of 20-30% polystyrene were thermoplastic elastomers with good recovery. When polystyrene contents were increased, the graft products were strong, flexible thermoplastics with well defined yield strengths and increased permanent set. Copolymers of polystyrene macromers with acrylonitrile or vinyl chloride produced transparent polystyrene homopolymer-free graft polymer products having improved processing over polyacrylonitrile or poly(vinyl chloride) homopolymers.
139 citations
TL;DR: In this article, the noise spectra up to mass 250 have been obtained using low damage conditions (i.e. ion current densities ∽1 nA cm−2) and electron beam charge neutralization.
Abstract: Seven polymers (low density polyethylene, polypropylene, polystyrene, polymethylmethacrylate, poly(methacrylic acid), Nylon-6 and poly(ethyleneterephthalate)) have been studied by SIMS. Very good signal: noise spectra up to mass 250 have been obtained using low damage conditions (i.e. ion current densities ∽1 nA cm−2) and electron beam charge neutralization. The spectra are highly characteristic and fairly easily interpreted using fragmentation data from electron impact mass spectrometry.
114 citations
TL;DR: In this article, the Tait equation was used to model the pressure-volume-temperature properties of poly(2,6-dimethyl-1,4-phenylene ether) with polystyrene (PS) in both the glassy and melt states.
Abstract: The pressure-volume-temperature (PVT) properties of blends of poly(2,6-dimethyl-1,4-phenylene ether) (PPO) with polystyrene (PS) have been studied experimentally in both the glassy and melt states at 0, 20, 40, 50, 60, 80, and 100% PPO content. In all compositions a strong glass transition was observed varying linearly with composition. For all but the 40% PPO composition this was the only transition, indicating molecular compatibility of the components in these blends. The 40% PPO composition showed a very weak second transition near the glass transition of pure PS. A small amount of phase separation may have occurred in this blend. The data for the glassy and melt states were fitted to an empirical equation of state based on the Tait equation. The volume of the melts at constant pressure and temperature showed a virtually linear dependence on composition. Any negative excess volume of mixing compatible with the data would have to be very small, smaller than expected from previous measurements in the glassy state. Various properties relating to the glassy and melt states and to the glass transition were evaluated and are discussed as a function of composition. It was found that most properties of the glasses could not be modeled by simple functions of composition.
85 citations
79 citations
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62 citations
TL;DR: In this article, the authors used dynamic mechanical and optical properties as a measure of compatibilization of polystyrene-vinyl pyridine and sulfonated polyisoprene polymer pair.
Abstract: Interactions between anions on one polymer chain with cations on another can lead to compatibilization of otherwise incompatible materials. Thus, if 5 mol% of ∼SO3H groups are attached to polystyrene, and 5 mol% of vinyl pyridine is copolymerized with ethyl acrylate, proton transfer occurs upon mixing, and the pairwise attractive interactions between the resultant ions compatibilize the blend. The same has been observed for the styrene-vinyl pyridine and sulfonated polyisoprene polymer pair. Dynamic mechanical and optical properties are used as a measure of compatibilization.
TL;DR: In this paper, the early stages of phase separation in liquid mixtures of polystyrene (PS) and poly(methylphenylsiloxane) were studied by light scattering.
Abstract: Early stages of phase separation in liquid mixtures of polystyrene (PS) and poly(methylphenylsiloxane) were studied by light scattering. Measurements were made at four concentrations less than 60 wt% PS and at several temperatures in the two-phase region. The time (t) dependence of maximum intensity of scattered light Im and the corresponding wave number km did not obey the Cahn theory but could be represented by power-laws: Im∝tθ and km∝tφ with θ=0.69 (±0.17) and φ=−0.29 (±0.05). These values of θ and φ agree well with those predicted by recent theories of Langer et al. and Binder et al. for spinodal decomposition, and also with the experimental values for binary mixtures of small molecules. It was concluded that there is no essential difference in the mechanism of phase separation between mixtures of small molecules and polymer blends.
TL;DR: In this article, the sorption and permeation of carbon dioxide gas in miscible blends of poly(phenylene oxide) and polystyrene was measured as a function of pressure at 35°C over the entire range of blend compositions.
TL;DR: In this paper, the authors show that typical pressure sensitive adhesives prepared from block polymers of butadiene or isoprene with styrene maintain the domain structure of the block polymer well beyond the polystyrene domain Tg, but form homogeneous melts above a critical temperature, Tc lies some 20°C below the usual hot melt processing temperature.
Abstract: Rheological and small angle x-ray scattering (SAXS) measurements show that typical pressure sensitive adhesives prepared from block polymers of butadiene or isoprene with styrene maintain the domain structure of the block polymer well beyond the polystyrene domain Tg, but form homogeneous melts above a critical temperature, Tc. For the examples investigated, Tc lies some 20°C below the usual hot melt processing temperature. The extremely high resistance to creep of the adhesives at service temperatures is explained as being the result of viscous flow with the domain structure in a state of dynamic equilibrium, in which polystyrene blocks are detached from domains and reattached to others. A transition between nonequilibrium and equilibrium domain structures is revealed clearly by SAXS for one of the block polymers used in this work.
TL;DR: In this article, a series of interpenetrating polymer networks, IPN's, and semi-1 IPNs of poly(n-butyl acrylate) and polystyrene were prepared.
Abstract: A series of interpenetrating polymer networks, IPN's, and semi-1 IPN's of poly(n-butyl acrylate) and polystyrene were prepared. The glass transition behavior via dynamic mechanical spectroscopy (DMS) and the morphology via transmission electron microscopy (TEM) were studied as a function of composition ratio and crosslink density. Transition-broadening was observed at low crosslink concentrations, while a single broad glass transition peak at an intermediate position was attained at high crosslink density levels. A cellular domain structure was the morphological characteristic of those IPN's and semi-1 IPN's possessing a low cross-link density and mid-range composition ratio. At higher levels of crosslink density, irregular shapes of the domain morphology prevailed. Phase connectivity was also observed at high polymer II compositions. Theoretical phase domain sizes of polymer II were calculated using both the theories developed by the present authors and that published earlier by Donatelli, et al., and were found to agree with the experimental domain sizes. While the theory was developed for uniform spheres, some of the domain structures observed experimentally for high polymer II contents had connectivity and/or a cylindrical shape.
TL;DR: The selectivity of the reaction of benzoyloxy radicals with styrene has been examined in this article, showing that 80% tail addition, 5% head addition, and 15% aromatic substitution are possible.
Abstract: The selectivity of the reaction of benzoyloxy radicals with styrene has been examined. Analysis of the products formed when benzoyl peroxide is decomposed in styrene at 60°C in the presence of a radical trapping agent (2,2,6,6-tetramethylpiperidine-1-oxyl) shows that the reaction of benzoyloxy radicals with styrene proceeds with 80% “tail” addition, 5% “head” addition, and 15% aromatic substitution. Phenyl radicals (formed by decarboxylation of benzoyloxy radicals) also may add to either the double bond or the aromatic ring of styrene. The importance of the above-mentioned processes to the structure and properties of benzoyl-peroxide-initiated polystyrene is discussed.
TL;DR: In this paper, small and wide-angle x-ray scattering results for a series of unneutralized and neutralized sulfonated polystyrenes are presented for the range of sulfonation from 0 to 7.26 mol %.
Abstract: Small- and wide-angle x-ray scattering results for a series of un-neutralized and neutralized sulfonated polystyrenes are presented for the range of sulfonation from 0 to 7.26 mol %. From the small-angle scattering it is shown that above the 3 mol % level for both the zinc and sodium salts, a Bragg spacing (37 A) and diameter (6.9-8.4 A) of the scattering unit can be calculated. When the concentration of salt is increased, there is no appreciable change in the latter two measurements. The wide-angle data indicate that the cations do not influence to any large extent the basic intramolecular and intermolecular structure of polystyrene. All the data are consistent with the onset of clustering above a critical ion concentration.
TL;DR: Partially 2-carboxylbenzoyl (1) and 3 carboxyl-2-naphthoyl substituted polystyrene were prepared by the Friedel-Crafts reaction of poly styrene with corresponding dicarboxylic anhydrides.
Abstract: Partially 2-carboxylbenzoyl (1) and 3-carboxyl-2-naphthoyl (2) substituted polystyrene were prepared by the Friedel-Crafts reaction of polystyrene with corresponding dicarboxylic anhydrides. Europium (III) salts of (1) and (2) and the copolymer of 4-vinylbenzoyl 2′-carboxylbenzoate-di(2-benzoyl benzoate) and styrene (5) were prepared. Polymer (5) was prepared by the copolymerization of the Eu3+ salt of 4-vinylbenzoyl 2′-benzoate and 2-benzoylbenzoate (ratio 1:2) with styrene. The fluorescence emission intensity was measured on fine powder samples. The intensity of (5) increased linearly as the Eu content increased. However, for the 1 and 2 systems the intensity reached a maximum at a Eu content as small as 0.5 wt% and remained constant when further increases were made. This phenomenon was accounted for by steric hindrance and a decrease in the freedom of bond rotation, which prevent the formation of multiple coordination linkages between Eu3+ and the benzoate groups.
TL;DR: In this article, the forces between mica surfaces a distance D apart immersed in cyclohexane, bearing adsorbed layers of polystyrene, have been measured at temperatures lower than the corresponding critical temperatures.
Patent•
31 Mar 1982
TL;DR: In this paper, an immunoassay of a specimen of a serum or the like to determine immune complexes, includes producing on a plastic base a layer of a non-proteinaceous, non-ionic polymer which will adhere to the plastic base and has the capability of absorbing immune complexes of the specimen, placing a specimen on the layer and treating the layer to produce an indication of the amount of immune complexes.
Abstract: An immunoassay of a specimen of a serum or the like to determine immune complexes, includes producing on a plastic base a layer of a non-proteinaceous, non-ionic polymer which will adhere to the plastic base and has the capability of absorbing immune complexes of the specimen, placing a specimen on the layer and treating the layer to produce an indication of the amount of immune complexes. The polymer may be polyethylene glycol, dextran, polyvinyl chloride, a polymeric polyol or an adduct of polyethylene glycol. Washing with conventional solutions, addition of an antihuman IgG coupled with an enzyme and addition of a substrate reactive therewith, are similar to the ELISA test, with color measurement as by spectrophotometer. Or, the addition of anti IgG-I 125 and measurement by a scintillation counter may be used. The ethylene glycol may range in molecular weight from 2,000 to 20,000, although 6,000 to 8,000 is preferred. A product for use in such an assay is a plate having wells or a test tube formed of plastic, polystyrene and polyvinyl chloride being preferred, with a layer of such non-proteinaceous, non-ionic layer on the plate wells or the cavity of the test tube. This product, if it is not to be used immediately, should be provided with a layer or film protecting the polymer layer from the air.
TL;DR: In this article, the phase separation process in Polymer Systems III. Spinodal Decomposition in the Critical Mixture of Polystyrene and Poly(methylphenylsiloxane) and Scaling Analysis
Abstract: Phase Separation Process in Polymer Systems III. Spinodal Decomposition in the Critical Mixture of Polystyrene and Poly(methylphenylsiloxane) and Scaling Analysis
Patent•
29 Mar 1982
TL;DR: In this paper, a small cells at junction points between membranes of polystyrene foam are formed by extruding poly styrene, nucleating agent, physical blowing agent, and water where the physical blowing agents and water are injected into extruder to provide blowing system.
Abstract: Forming polystyrene foam by extruding polystyrene, nucleating agent, physical blowing agent, and water where the physical blowing agent and water are injected into extruder to provide blowing system. The product produced has small cells at junction points between membranes of the foam.