Crystallization in Butadiene-Styrene Copolymers

1955 ◽  
Vol 28 (1) ◽  
pp. 51-56
Author(s):  
Lawrence A. Wood
Keyword(s):  
Experimental Observation ◽  
Polymerization Temperature ◽  
Styrene Copolymers ◽  
Styrene Content ◽  
Butadiene Styrene

Abstract From Figure 3 one draws the following significant conclusions: (1) Crystallization is not observed if the polymerization temperature is above 60° C. (2) For polymerization at 50° C, a small amount (2 to 6 per cent) of bound styrene inhibits crystallization completely. (3) For polymerizations at 5° C, the limit is at about 15 to 18 per cent bound styrene content. (4) At the lowest polymerization temperatures normally utilized, this limit is at about 30 per cent bound styrene. Direct experimental observation is in general accord with these conclusions.

Styrene-Diene Resins in Rubber Compounding

1947 ◽  
Vol 20 (1) ◽  
pp. 241-248
Author(s):  
A. M. Borders ◽  
R. D. Juve ◽  
L. D. Hess
Keyword(s):  
Tensile Elongation ◽  
Chemical Properties ◽  
Aryl Hydrocarbon ◽  
Styrene Copolymers ◽  
Synthetic Rubber ◽  
Brittle Point ◽  
Styrene Content ◽  
Physical And Chemical ◽  
Preparation And Evaluation ◽  
Butadiene Styrene

Abstract Early in the investigation of butadiene-styrene copolymers as synthetic rubbers, this laboratory became interested in copolymers containing much more styrene than any of the American or German synthetics. This interest was soon directed to the resinous copolymers obtained when the styrene content is increased beyond the range in which rubberlike properties are observed at room temperature. The exploratory work, therefore, involved preparation and evaluation of butadiene-styrene copolymers containing from 65 to 98 per cent styrene. No description of similar polymers has been found. Konrad and Ludwig claimed the improvement of rubberlike properties of butadiene-styrene copolymers by increasing the styrene content from the normal range to “between about 47.5 and about 70 per cent”. The claims and examples of this patent emphasize the improvement of rubberlike properties, such as tensile, elongation, and rebound, at high temperatures. It is well known in this country, however, that increase in styrene content beyond a certain point, perhaps 50–55 per cent, is accompanied by a loss of overall balance of rubber characteristics. Therefore, the copolymers at the upper end of the range described by Konrad and Ludwig have definite limitations for rubber uses—for example, low rebound, high brittle point, shortness, etc. In the writers' laboratory useful resins have been prepared from dienes and vinyl aryl hydrocarbons in the range 5 to 20 per cent diene and 80 to 95 per cent vinyl aryl hydrocarbon. This paper describes the properties and certain uses of one of these copolymers containing approximately 15 parts of butadiene and 85 parts of styrene. This material possesses a combination of physical and chemical properties which permit its use in several applications where cyclized natural or synthetic rubbers are commonly employed. Cyclized natural rubber has been described by Bruson, Endres, and Thies and Clifford. Cyclized synthetic rubbers were described recently by Endres. One product of this type is made from a special synthetic rubber. The new 15 butadiene—85 styrene copolymer is now identified as Pliolite S-3, since it may be used in many Pliolite applications, often with distinct advantages over either the natural or synthetic rubber derivatives.

LABORATORY STUDY OF LOW RATIO BUTADIENE–STYRENE COPOLYMERS

1949 ◽  
Vol 27f (2) ◽  
pp. 35-46 ◽  
Author(s):  
J. M. Mitchell ◽  
H. Leverne Williams
Keyword(s):  
Induction Period ◽  
Chain Transfer ◽  
Viscosity Data ◽  
Reactivity Ratios ◽  
Styrene Copolymers ◽  
Rate Of Reaction ◽  
Styrene Content ◽  
Mass Basis ◽  
Dodecyl Mercaptan ◽  
Butadiene Styrene

The copolymerization of styrene and butadiene in ratios in which the styrene equals or predominates over the butadiene on a mass basis is essentially similar to copolymerization in the presence of a predominance of butadiene. However, the rate of reaction and the length of the induction period is increased. Increasing the amount of the dodecyl mercaptan regulator results in a slight increase in rate and diminution of the induction period. The dodecyl mercaptan reacts at a lower rate than during the production of GR–S. The regulating index as defined by the ratio of the logarithm of the residual mercaptan over the conversion is 1.53. The bound styrene and increment styrene curves seem to be normal and indicate reactivity ratios r1 (butadiene) equal to 1.4 to 2.2, r2 equal to 0.5 to 0.7. If these reactivity ratios are corrected for the bifunctional nature of butadiene then the constants for butadiene monomer are Q equal to 0.9 and e equal to − 1. Likewise the gel–viscosity data are similar to those observed with GR–S except that the pre-gel rise in viscosity, the formation of gel, and the slope of the viscosity conversion curves diminish with increasing styrene in the charge. The chain transfer action of styrene is increasingly evident with increasing styrene content in the charge but in all cases the regulating effect of dodecyl mercaptan is still apparent.

Spectrophotometric Determination of the Styrene Content of Butadiene-Styrene Copolymers

1946 ◽  
Vol 19 (4) ◽  
pp. 1077-1084 ◽  
Author(s):  
E. J. Meehan
Keyword(s):  
Molecular Weight ◽  
Spectrophotometric Determination ◽  
Extinction Coefficient ◽  
Ultraviolet Spectrophotometry ◽  
Relative Precision ◽  
Specific Extinction Coefficient ◽  
Styrene Copolymers ◽  
Styrene Content ◽  
Butadiene Styrene

Abstract The ultraviolet absorption of polystyrene, with maximum absorption at 262 mµ, is due to the presence of phenyl residues in the polymer. The specific extinction coefficient is constant, i.e., independent of the molecular weight of the polymer. This shows that the extinction of the phenyl residues is additive. On the basis of this fact, it is shown that the styrene content of a butadiene-styrene copolymer (such as GR-S rubber) can be determined by ultraviolet spectrophotometry. The relative precision of the determination is about 1 per cent, the probable relative accuracy is about 3 per cent.

The Effect of Comonomer on the Microstructure of Butadiene Copolymers

1953 ◽  
Vol 26 (4) ◽  
pp. 832-839
Author(s):  
Frederick C. Foster ◽  
John L. Binder
Keyword(s):  
Infrared Absorption ◽  
Theoretical Explanation ◽  
Experimental Results ◽  
Vinyl Monomers ◽  
Styrene Copolymers ◽  
Wide Range ◽  
Styrene Content ◽  
Comonomer Content ◽  
Butadiene Styrene

Abstract The microstructure of butadiene-styrene copolymers having a wide range of styrene contents has been determined by infrared absorption. The results demonstrate that the percentage of trans-1,4-addition increases, the 1,2-addition decreases, and the cis-1,4-addition decreases as the styrene content is increased. Similar measurements of five other butadiene copolymer systems indicate that all these vinyl monomers, acrylonitrile, methacrylonitrile, methylvinyl ketone, vinylpyridine, and α-methylstyrene, change the microstructure in the same direction as styrene, differing only in the magnitude of their effect. A theoretical explanation, consistent with the experimental results obtained, is given for the change in microstructure with comonomer content.

Plastic Yield of Butadiene-Styrene and Isoprene-Styrene Ebonites

1951 ◽  
Vol 24 (2) ◽  
pp. 381-383 ◽  
Author(s):  
J. R. Scott
Keyword(s):  
Plastic Deformation ◽  
Natural Rubber ◽  
Elevated Temperatures ◽  
Styrene Copolymer ◽  
Heat Resistant ◽  
Plastic Yield ◽  
Styrene Copolymers ◽  
Styrene Content ◽  
Butadiene Styrene

Abstract In unloaded ebonites made from butadiene-styrene copolymers, the resistance to plastic deformation at elevated temperatures is better the higher the styrene content of the copolymer, at least up to 46 per cent. An isoprene-styrene copolymer ebonite has poorer plastic-yield resistance than a corresponding butadiene-styrene ebonite. All the styrene-containing copolymers, however give ebonites more heat-resistant than natural rubber ebonite, the best giving yield temperatures 30° C above the latter. To attain the best plastic-yield resistance in butadiene-styrene ebonites, the amount of sulfur added should correspond to more than 1 atom (e.g., 1.2 or even 1.4 atoms) per butadiene molecule.

THE COMPOSITIONAL HETEROGENEITY OF BUTADIENE-STYRENE COPOLYMERS SYNTHESIZED AT −18°C. IN EMULSION

1951 ◽  
Vol 29 (3) ◽  
pp. 270-283 ◽  
Author(s):  
R. J. Orr ◽  
H. Leverne Williams
Keyword(s):  
Transfer Reaction ◽  
Chain Transfer ◽  
Polymerization Temperature ◽  
Viscosity Data ◽  
Compositional Heterogeneity ◽  
Molecular Weights ◽  
Styrene Copolymers ◽  
Chain Transfer Reaction ◽  
Molecular Weight Heterogeneity ◽  
Butadiene Styrene

A study has been made of butadiene-styrene copolymers formed at −18°C. From analyses for bound styrene in the product for various conversions and initial butadiene-styrene ratios the reactivity ratios were calculated to be r1 = 1.37 and r2 = 0.38 compared with 1.8 and 0.6 at 45°C. Q and e for butadiene were 1.38 and 0.008 relative to styrene at 1 and −0.8. Increment bound styrene curves calculated for each stage of the reaction indicated that the polymers were remarkably homogeneous at low conversions. The chain transfer reaction using mixed tertiary mercaptans as the modifier was studied. Regulating indices were found to have decreased with polymerization temperature. Number average [Formula: see text] and viscosity average [Formula: see text] molecular weights were calculated from mercaptan disappearance and vistex intrinsic viscosity data respectively. The molecular weight heterogeneity increased with increasing conversion and initial mercaptan content. The increment number average molecular weights were found to diminish with conversions, whereas the increment viscosity average increased at higher conversions as conversion increased.

Evaluation of Sodium-Catalyzed Copolymers of 1,3-Butadiene and Styrene

1948 ◽  
Vol 21 (2) ◽  
pp. 452-460
Author(s):  
A. E. Juve ◽  
M. M. Goff ◽  
C. H. Schroeder ◽  
A. W. Meyer ◽  
M. C. Brooks
Keyword(s):  
High Temperature ◽  
Free Radical ◽  
Low Temperature ◽  
Crack Growth ◽  
Monomer Composition ◽  
Styrene Copolymers ◽  
Identical Monomer ◽  
Emulsion Polymers ◽  
Styrene Content ◽  
Butadiene Styrene

Abstract Sodium-catalyzed butadiene-styrene copolymers (S-BS), of composition 75 weight-per cent butadiene: 25 weight-per cent styrene, have been compounded in tread type recipes. Evaluation tests showed properties significantly different from those of GR-S, the emulsion-phase free radical—catalyzed copolymers of identical monomer composition. 1. The processing characteristics of S-BS are considerably superior to those of GR-S, although one experience with a high temperature internal mix may indicate some limitation. Objective laboratory processing tests show that S-BS resembles high-styrene emulsion copolymers in that it can be satisfactorily fabricated from stocks containing less filler than is required in GR-S stocks for similar uses. 2. Stress-strain properties based on limited compounding studies are similar to those of GR-S. 3. The flex crack growth—hysteresis balance for S-BS vulcanizates is much superior to that of GR-S vulcanizates. Vulcanizates of emulsion polymers of high styrene content also had a flex crack growth—hysteresis balance superior to that of GR-S vulcanizates. 4. The low temperature properties of S-BS vulcanizates are inferior to those of GR-S vulcanizates. Brittle points and low temperature Young's modulus of S-BS vulcanizates are much higher than those of GR-S vulcanizates.

X-Ray Studies of Low-Temperature Polybutadiene and Butadiene-Styrene Copolymers

1949 ◽  
Vol 22 (2) ◽  
pp. 356-369 ◽  
Author(s):  
Karl E. Beu ◽  
W. B. Reynolds ◽  
C. F. Fryling ◽  
H. L. McMurry
Keyword(s):  
Molecular Weight ◽  
Low Temperature ◽  
Polymer Chains ◽  
Polymerization Temperature ◽  
X Ray ◽  
Styrene Copolymers ◽  
Emulsion Polymerizations ◽  
Diffraction Patterns ◽  
Ray Patterns ◽  
Butadiene Styrene

Abstract Although it is now generally recognized that the temperature of polymerization affects profoundly the properties of emulsion elastomers, there is very little evidence available pertaining to the cause of the variations of properties. It is felt by some that the improved properties of low-temperature elastomers can be related to variations in molecular weight and molecular-weight distribution. In this laboratory, however, the opinion has prevailed that the lower emulsion polymerization temperatures appreciably alter the fine structure of the molecules with an increase in the regularity of the polymer chains. If there were actually less branching and cross-linking in low-temperature polymers, and less 1,2-addition to monomer components, the increased order should be evident from x-ray diffraction patterns. To provide information on the above questions, x-ray studies were made with four purposes in view: (1) to determine the effect of polymerization temperature on the crystallization properties of unstretched and stretched polybutadienes; (2) to determine the influence of styrene content on the crystallization of butadiene-styrene copolymers; (3) to study some effects of compounding and vulcanization on crystallizable polybutadiene; and (4) to use the preferred orientation patterns obtained from some of these polymers for structural evaluations. To accomplish these objectives, x-ray patterns were obtained at several temperatures of some unstretched and stretched polybutadiene polymers, butadiene-styrene copolymers, and a vulcanized and compounded polybutadiene. The polybutadienes were prepared by emulsion polymerizations at 55°, 40°, 30°, 20°, 5°, −10° and −20° C. Since the −20° C polybutadiene showed the most marked crystallization patterns, the effects of compounding and of styrene addition were studied, using polymers prepared at this temperature for comparison. Three butadiene-styrene copolymers containing, respectively, 10, 20, and 30 per cent styrene in the monomer charge and one vulcanized polybutadiene compounded with Wyex carbon black were studied.

Effect of styrene–butadiene–styrene content on the adhesion properties of bitumen before and after heat aging

2008 ◽  
Vol 35 (5) ◽  
pp. 454-460 ◽  
Author(s):  
Krzysztof Zieliński
Keyword(s):  
Adhesion Strength ◽  
Test Results ◽  
Adhesion Properties ◽  
Before And After ◽  
Styrene Content ◽  
Styrene Butadiene Styrene ◽  
Styrene Butadiene ◽  
Steel Substrates ◽  
Butadiene Styrene

This article describes the effect of heat aging and styrene–butadiene–styrene (SBS) content in bitumen on the adhesion properties of mastics (bitumen-filler mix) to concrete and steel substrates. Test results showed that the adhesion strength of bituminous mastics to concrete and steel substrates decreased as the SBS content increased. Bitumen types modified with 9%–12% of SBS, commonly used in waterproofing materials, showed an approximately three times weaker bond with concrete and steel substrates than the nonmodified equivalents. Results also showed that after heat aging, the adhesion strength of the nonmodified bitumen was always higher than that of the unheated bitumen modified with 9%–12% of SBS.

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