Showing papers on "Styrene-butadiene published in 1968"
TL;DR: In this paper, the physical properties of styrene-butadiene block copolymers are reported for a number of different kinds synthesized by the Living Polymer Technique (LPT).
82 citations
52 citations
TL;DR: Several narrow molecular weight distribution block copolymers were prepared by a two-stage anionic polymerization technique as mentioned in this paper, and the films cast from these solutions were studied by electron microscopy.
Abstract: Several narrow molecular weight distribution block copolymers were prepared by a two-stage anionic polymerization technique. Films cast from these solutions were studied by electron microscopy. Replicas showed that the film surfaces were composed of layered structures with various orientations. Micrographs of ultrathin sections of stained films demonstrate that layered structure occur throughout the film. The widths of the copolymer layer spacings increase with increasing molecular weight and agree quite well with the calculated values.
48 citations
01 Mar 1968
TL;DR: In this article, the authors described the dialysis, the determination of the total soap content in the latex system by conductometric titration, the effect of dilution on soap distribution between the aqueous and polymer phases, the confirmation of the average diameter of the latex particles, the electrophoretic behavior, and the establishment of the solids content below which the latex behaves according toBeer's law for the transmission of light.
Abstract: SummaryThis work describes the dialysis, the determination of the total soap content in the latex system by conductometric titration, the effect of dilution on soap distribution between the aqueous and polymer phases, the confirmation of the average diameter of the latex particles, the electrophoretic behavior, and the establishment of the solids content below which the latex behaves according toBeer's law for the transmission of light. The colloidal system used in this study was a styrenebutadiene (∼ 1∶1) latex (Naugatex 2740) with potassium salt of the disproportionated rosin (Dresinate 214) as emulsifier.ZusammenfassungAn einem Styrol-Butadien (∼1∶1)-Latex (Naugatex 2740) mit dem Kaliumsalz von disproportioniertem Harz (Dresinate 214) als Emulgator wurden folgende Untersuchungen durchgeführt: Dialyse, konduktometrische Bestimmung der Gesamtkonzentration an Seife im Latex, Einfluß der Verdünnung auf die Verteilung der Seife zwischen wässeriger und polymerer Phase, Ermittlung des mittleren Durchmessers der Partikel und elektrophoretisches Verhalten. Weiterhin wurde noch festgestellt, bis zu welchem Feststoffgehalt dasBeersche Gesetz für die Latexssuspension gilt.
25 citations
TL;DR: In this article, the viscoelastic properties of three samples of a random styrene-butadiene co-polymer with 23.5 wt% styrene, cross-linked by dicumyl peroxide to different extents, have been studied by dynamic shear and shear creep measurements, and the unvulcanized precursor has been studied in creep.
Abstract: The viscoelastic properties of three samples of a random styrene‐butadiene co‐polymer with 23.5 wt‐% styrene, cross‐linked by dicumyl peroxide to different extents, have been studied by dynamic shear and shear creep measurements, and the unvulcanized precursor has been studied in creep. The frequency and temperature ranges were 0.2 to 3600 cps and −30 to 55°C. The creep data were converted to the corresponding dynamic viscoelastic functions at very low frequencies. All data were reduced to T0=298°K by shift factors calculated from the equation log aT=−4.57(T−T0)/(113.6+T−T0). By fitting the creep to a modification of the empirical equation of Thirion and Chasset, values of the equilibrium compliance and relaxation parameters were obtained in good agreement with results of those authors from stress relaxation in extension. All the viscoelastic functions displayed two principal regions of frequency dependence as found for other rubberlike polymers. The high‐frequency dispersion, near 105 on the radian frequ...
24 citations
Patent•
20 Mar 1968TL;DR: In this paper, a block coprolymers are provided with POLYVINYL ARENE END BLOCKS and a HIGHLY HYDROXYLATED CONJUGATED DIENE CENTER BLOCK CAPABLE OF SWELLING IN WATER and other HYDROGEN BONDING SOLVENTS.
Abstract: BLOCK COPOLYMERS ARE PROVIDED WHICH HAVE POLYVINYL ARENE END BLOCKS AND A HIGHLY HYDROXYLATED CONJUGATED DIENE CENTER BLOCK CAPABLE OF SWELLING IN WATER AND OTHER HYDROGEN BONDING SOLVENTS.
23 citations
TL;DR: In this paper, temperature dependence of dielectric loss, mechancial loss, and dynamic modulus were measured to study polymer blending, and the results indicated that the blends were microheterogeneous.
Abstract: Temperature dependence of dielectric loss, mechancial loss, and dynamic modulus were measured to study polymer blending. Results were as follows: Dielectric loss and dynamic modulus of NR—BR blends showed two peaks corresponding to NR and BR, indicating that the blends were microheterogeneous. A single, broad maximum absorption band observed for SBR—BR blends indicated that the blends were microhomogeneous. Mill mixing and solution mixing of NR and BR made very little difference in blended state and physical properties. Nearly homogeneous SBR—BR blends can be obtained with a few minutes mill mixing. In vulcanization of NR—BR blends, BR was overcured rapidly due to migration of sulfur and accelerators from NR.
22 citations
TL;DR: In this paper, DICKENSON'S HYPOTHESIS is that the BIOLOGIC degradation of the RUBBER MUST be PRECEDED by a NORMAL OXIDATION PROCESS that BREAKS the long HYDROCARBON CHAIN into SHORTER MOLECULES WHICH then may be CONSUMED.
Abstract: DEGRADATION HAS BEEN REPORTED OF NATURAL RUBBER GASKETS USED FOR SEALING PIPE JOINTS OF ASBESTOS-CEMENT PIPES IN THE NETHERLANDS. THE DEGRADATION WAS CAUSED BY THE ATTACK OF SPECIFIC BACTERIA OF THE GENUS STREPTOMYCES. THE ABILITY OF THESE ORGANISMS TO CONSUME THE HYDROCARBON OF VULCANIZED NATURAL RUBBER WAS CONFIRMED BY PURE CULTURE TESTS. SYNTHETIC RUBBER COMPOUNDS PROVED TO BE RESISTANT, WITH THE EXCEPTION OF SYNTHETIC POLYISOPRENE, THE HYDROCARBON COMPONENT OF NATURAL RUBBER. DICKENSON'S HYPOTHESIS IS THAT THE BIOLOGIC DEGRADATION OF THE RUBBER MUST BE PRECEDED BY A NORMAL OXIDATION PROCESS THAT BREAKS THE LONG HYDROCARBON CHAIN INTO SHORTER MOLECULES WHICH THEN MAY BE CONSUMED. BACTERIOLOGIC WORKS SHOW THE UTILIZATION OF VARIOUS ALIPHATIC HYDROCARBONS BY BACTERIA. A REPRESENTATIVE NUMBER OF AMERICAN GASKETS WERE TESTED WITH REGARD TO THEIR RESISTANCE TO BIOLOGICAL ATTACK, UNDER EXACTLY THE SAME CONDITIONS THE DUTCH RINGS WERE TESTED. NONE OF THE SYNTHETIC COMPOUNDS, INCLUDING NITRILE, NEOPRENE, ETHYLENE- PROPYLENE AND STYRENE-BUTADIENE RUBBER WAS ATTACKED. THE RESISTANCE OF SYNTHETIC RUBBER COMPOUNDS WAS CONFIRMED. ALL NATURAL RUBBER AND SYNTHETIC POLYISOPRENE RUBBERS WERE ATTACKED. THE THREE MIXED COMPOUNDS OF NATURAL RUBBER OR POLYISOPRENE WITH ADDED SYNTHETIC ELASTOMER STYRENE BUTADIENE RUBBER (SBR) ARE ALL VERY RESISTANT. THE RATIO OF NATURAL RUBBER AND SBR IN THESE MIXTURES IS UNKNOWN. THE GREATER RESISTANCE TO BIOLOGIC ATTACK IN THE U. S. MAY BE DUE TO DIFFERENT WATER CONDITIONS.
14 citations
6 citations
TL;DR: In this article, the discrepancy between the reported values reported for the weight-average molecular weight and molecular weight distribution of cold-type styrene-butadiene rubber is examined.
Abstract: The discrepancy between the values reported for the weight-average molecular weight and molecular weight distribution of cold-type styrene-butadiene rubber is examined. The results obtained indicate that aggregation of the rubber due to hydrogen bonding or cluster formation is not a contributing factor to the high weight-average molecular weights obtained. The very broad molecular weight distributions, the Mw/Mn of the order of 10–20, are attributable to the presence of a few per cent of very high molecular weight fraction microgel in samples polymerized to moderate conversions. This microgel has been removed to various degrees by several methods: (1) mastication, (2) treatment with CaSO4, (3) ultracentrifugation, and (4) ultrafiltration. The nature of this microgel is examined in terms of its light-scattering property, intrinsic viscosity, and concentrated solution viscosity. The weight-average molecular weight obtained by light scattering on these samples after removal of microgel are lower by as much as an order of magnitude. The operational definition of the weight-average molecular weight, M′w, is therefore introduced, corresponding to the one obtained after removal of the microgel. It is suggested that the actual and the operational weight-average molecular weights be used in conjunction in the characterization of these copolymers.
6 citations
Patent•
18 Jun 1968TL;DR: An improved version of the Web is described in this paper, where the authors describe an improved, synthietic, MICROPOROUS VAPOR PERMEABLE SUEDE-LIKE SHEET MATERIAL of a non-woveen SYNTHETIC FLEXIBLE FIBROUS WEB that is impregnated with a POLYMERIC BINDER of StyrENE and Butadiene.
Abstract: AN IMPROVED SUPPLE, SYNTHETIC, MICROPOROUS VAPOR PERMEABLE SUEDE-LIKE SHEET MATERIAL OF A NON-WOVEN SYNTHETIC FLEXIBLE FIBROUS WEB THAT IS IMPREGNATED WITH A POLYMERIC BINDER OF STYRENE AND BUTADIENE AND THE POLYMERIC BINDER CONTAINS ABOUT 0.1-10 PARTS IF A SILICONE OIL ADDITIVE PER 100 PARTS OF POLYMERIC.
Patent•
06 Feb 1968
TL;DR: In this paper, a process for the production of split-headed Stylenebutadioene COPOLYMERS from a CORRESPONDING COARSER COPOLINESSMER COMPOSITION is described, where the non-solvents have a higher boiling point than the solvents.
Abstract: A PROCESS FOR THE PRODUCTION OF FINELY DIVIDED STYRENEBUTADIENE COPOLYMERS FROM A CORRESPONDING COARSER COPOLYMER COMPOSITION WHICH COMPRISES DISSOLVING THE COARSER MATERIAL IN A HOMOGENEOUS SOLVENT MIXTURE WHICH CONSISTS OF AT LEAST ONE SOLVENT FOR THE COPOLYMER, AND AT LEAST ONE SOLVENT FOR THE COPOLYMER, THE NON-SOLVENT PART HAVING A HIGHER BOILING POINT THAN THAT OF THE SOLVENT; THEREAFTER REMOVING FROM THE MIXTURE BY VACUUM DISTILLATION THE SOLVENT PORTION TO AN EXTENT AT LEAST SUFFICIENT THAT THE DISSOLVED COPOLYMER IS PRECIPITATED IN THE FORM OF A DISPERSION, AND FINALLY PURIFYING THE MATERIAL THUS PRECIPITATED BY TREATING IT WITH FURTHER NON-SOLVENT WHICH IS HOMOGENEOUSLY MISCIBLE WITH THE RESIDUAL LIQUID
01 Jan 1968
TL;DR: SBR as discussed by the authors 후일 별도로 논술키 한 하다.
Abstract: SBR의 가공기술은 이미 널리 보급되어 있으므로 본고에서는 미국에서의 SBR개발과정을 중점적으로 다루고 사용기술 및 용도에 대해서는 기본적인 요점만 해설키로 한다. SBR의 용도별 전문적인 가공기술은 후일 별도로 논술키로 한다.