Rate of Adsorption of High Polymers on Carbon Black in Relation to Their Molecular Weight

1956 ◽  
Vol 29 (4) ◽  
pp. 1300-1302 ◽  
Author(s):  
A. I. Yurzhenko ◽  
I. I. Maleev
Keyword(s):  
Molecular Weight ◽  
Carbon Black ◽  
Butyl Acetate ◽  
Benzene Solution ◽  
Plant Sample ◽  
Fractional Precipitation ◽  
Characteristic Viscosity ◽  
Molecular Substances ◽  
Work Samples ◽  
Molecular Compounds

Abstract The nature and rate of adsorption of high-molecular substances on carbon black is of interest in a number of instances, particularly in the development of adsorption methods of fractionation of high-molecular substances, but also in the use of carbon black as a filler for rubber ; the number of papers on the adsorption of high-molecular compounds is small. The effect of the molecular weight of different polymers on the rate of adsorption of high-molecular substances from their dilute solutions at C=0.1–0.25 per cent was studied in this work. Samples of polyisoprene, polystyrene, emulsion polymerization at a temperature of +5° and +50°, and also a plant sample of SKS-30 rubber, were the objects of the investigation. Moreover, a series of polystyrene fractions was obtained by the method of fractional precipitation from methyl ethyl ketone and butyl acetate, using methanol as the precipitant. For all the polymers and their fractions the characteristic viscosity was determined, from which the molecular weight value of the polymer was determined. Carbon black of the Ukhtinsky and Dashavsky factories was used as the adsorbent, the specific surface of which was determined by the adsorption of acetic acid from a benzene solution.

Sorption of GR-S Type of Polymer on Carbon Black. III. Sorption by Commercial Blacks

1953 ◽  
Vol 26 (1) ◽  
pp. 102-114 ◽  
Author(s):  
I. M. Kolthoff ◽  
R. G. Gutmacher
Keyword(s):  
Molecular Weight ◽  
Carbon Black ◽  
Intrinsic Viscosity ◽  
Benzene Solution ◽  
Weight Fraction ◽  
High Molecular Weight Fraction ◽  
Molecular Weights ◽  
Bound Rubber ◽  
Flow Through ◽  
Peculiar Behavior

Abstract The sorption capacities toward GR-S five commercial carbon blacks are in decreasing order: Spheron-6, Vulcan-1, Philblack-0, Sterling-105, Philblack-A. Apparently, the sorption is not related to surface area. The sorption on Vulcan-1 of GR-S from its solutions in seven different solvents or mixtures of solvents increases with decreasing solvent power for the rubber. The sorption curves of two “cold rubbers,” polymerized at −10 and +5° respectively, showed little difference from that of 50° GR-S. Previous heating of carbon black in nitrogen at 500 or 1100° increased the sorption by about 20 per cent over unheated carbon. Air-heating of carbon black at 425° did not cause a difference in the sorption from benzene solution, but produced an increase in the sorption of rubber from n-heptane solution. In the range 75% butadiene-25% styrene to 5% butadiene-95% styrene, there is practically no effect of the degree of unsaturation on the sorption. Polystyrene of high intrinsic viscosity exhibits a peculiar behavior with furnace blacks. Vulcan-1 sorbed microgel as well as the sol fraction from n-heptane solutions of GR-S containing microgel (conversion 74.7 and 81.5 per cent). There was no appreciable difference in the amount of sorption of rubber fractions having average molecular weights varying from 433,000 to 85,000. There is little change in the amount sorbed after two hours of shaking, but the intrinsic viscosity of the residual rubber decreases with time. The low molecular-weight rubber is sorbed more rapidly, but is slowly replaced by the more tightly sorbed high molecular weight fraction. Partial fractionation of a rubber sample can be achieved by allowing the rubber solution to flow through a column of weakly sorbing carbon black. A large portion of the sorbed rubber can be recovered from the column by washing it with a good solvent such as xylene. Bound rubber is produced by intimate mixing of equal parts of carbon black and rubber swollen in chloroform, when the mixture is dried in vacuum at 80° or at room temperature. Milling is not essential to get bound rubber.

Isoprene and Rubber. Part 32.The Constitution of Rubber

1931 ◽  
Vol 4 (3) ◽  
pp. 368-380
Author(s):  
H. Staudinger
Keyword(s):  
Molecular Weight ◽  
Colloidal Particles ◽  
Molecular Size ◽  
Group Method ◽  
Decomposition Products ◽  
True Solution ◽  
Rubber Part ◽  
Molecular Substances ◽  
Molecular Compounds ◽  
End Group

Abstract 1. The establishment of the molecular size of high molecular compounds which are composed of fiber molecules by the end-group method of determination is only possible if homologous polymeric series of similar type are concerned. 2. The end-group method assures reliable values with molecules up to a molecular weight of 1000 at the highest. With higher molecular products, like cellulose and rubber, the method is inexact. 3. The molecular weight of rubber and balata may be determined by viscosity determinations in the following two ways: (a) M=ηsp/cKm (b) M=Kc.Kcm. The constants Km and Kcm are determined with low molecular decomposition products. 4. Rubber and balata are composed of fiber molecules, which in one dimension have the magnitude of colloidal particles and in both the others, the dimensions of low molecular substances. 5. In highly viscous rubber solutions, there is the characteristic state of solution. As a result, the sphere of action of the dissolved molecule is greater than the volume at the disposal of the solution. This solution is midway between a true solution and a gel, and is therefore designated as a gel solution. It occurs only with high molecular substances, and is characteristic of them. 6. The readiness with which rubber solutions vary is explained by the fact that the rubber molecules are very sensitive to chemical influences and to changes in temperature as a result of the position of the double bonds. This sensitivity varies with the length of the molecules.

scholarly journals Purification and properties of two extracellular β-lactamases from Bacillus cereus 569/H

1970 ◽  
Vol 118 (3) ◽  
pp. 457-465 ◽  
Author(s):  
S. Kuwabara
Keyword(s):  
Molecular Weight ◽  
Bacillus Cereus ◽  
Zinc Sulphate ◽  
Deae Cellulose ◽  
Casein Hydrolysate ◽  
Crystalline Form ◽  
Casamino Acid ◽  
Fractional Precipitation ◽  
Purification And Properties ◽  
Rapid Production

1. When Bacillus cereus 569/H was grown in a casamino acid (casein-hydrolysate) medium containing zinc sulphate rapid production of extracellular β-lactamase II preceded that of β-lactamase I. 2. β-Lactamase I was separated from β-lactamase II by fractional precipitation with ammonium sulphate. 3. β-Lactamase I was purified by a process involving chromatography on Celite and DEAE-cellulose and β-lactamase II by chromatography on DEAE-cellulose after denaturation of β-lactamase I by heat. Both enzymes were obtained in crystalline form. 4. β-Lactamase II prepared in this way appeared to have a higher molecular weight than β-lactamase I and required Zn2+ as a cofactor for both cephalosporinase and penicillinase activities.

scholarly journals High temperature transformation of tar-asphaltene components of oil sand bitumen

2017 ◽  
Vol 82 (9) ◽  
pp. 1063-1073 ◽  
Author(s):  
Yerzhan Imanbayev ◽  
Yerdos Ongarbayev ◽  
Yerbol Tileuberdi ◽  
Evgeniy Krivtsov ◽  
Anatoly Golovko ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Molecular Weight ◽  
Infrared Spectroscopy ◽  
Thermal Processing ◽  
Molecular Structures ◽  
Natural Bitumen ◽  
Oil Sand ◽  
Before And After ◽  
Temperature Transformation ◽  
Molecular Compounds

Transformations of high-molecular-weight compounds of oil sand natural bitumen under the heat treatment were studied in this work. For that purpose the natural bitumen isolated from oil sand taken from the Beke field (Kazakhstan) was used as a substrate. Thermal processing of natural bitumen leads to a general change in the chemical composition of components and to an increase in the output of certain fractions. The contents of oil, tar and asphaltenes were determined and the elemental composition of tar-asphaltene compounds was evaluated. Molecular structures of the tar and asphaltene components of natural bitumen before and after cracking have been defined from the data of elemental analysis, NMR spectroscopy and molecular weight. The high molecular compounds were presented as giant molecules containing small aromatic islands some of which were linked by aliphatic chains, that was proved by infrared spectroscopy.

Mixing of Carbon Black with Rubber. VI. Analysis of NR/SBR Blends

1988 ◽  
Vol 61 (4) ◽  
pp. 609-618 ◽  
Author(s):  
George R. Cotten ◽  
Lawrence J. Murphy
Keyword(s):  
Molecular Weight ◽  
Carbon Black ◽  
High Molecular Weight ◽  
Surface Area ◽  
Bound Rubber ◽  
Very High

Abstract The distribution of carbon black in NR/SBR blends was determined through the analysis of bound rubber. The NR/SBR blends were found to be very different from the previously studied SBR/BR compounds: these differences were assigned to mutual insolubility of the two polymers and a very high molecular weight of NR. In NR/SBR blends, it was found that changes in molecular weight of the polymer has no effect on the carbon black distribution in the blend. While the “activity” of carbon black did not affect the distribution, the loading of the black in NR decreased linearly with increasing surface area of the black. Approximately 35% of normal tread blacks (surface area 80–100 m2/g) was found in the NR phase. However, the bond between NR and carbon black is quite weak, and black continues to migrate into the SBR phase on prolonged mixing or during blending of NR and SBR masterbatches.

Effect of Mechanical Shear on the Structure of Carbon Black in Reinforced Elastomers

1970 ◽  
Vol 43 (5) ◽  
pp. 943-959 ◽  
Author(s):  
A. M. Gessler
Keyword(s):  
Molecular Weight ◽  
Carbon Black ◽  
Related Result ◽  
Critical Factor ◽  
Aggregate Structure ◽  
Carbon Black Concentration ◽  
Roll Mill ◽  
Total Structure ◽  
High Structure ◽  
High Shearing

Abstract The primary aggregate structure in high structure blacks is broken down when the blacks are milled in rubber. The breakdown, it is shown further, involves the disruption initially of more easily disrupted forces, and then subsequently of more difficultly disrupted forces. If the total structure breakdown is segmented accordingly, one finds that carbon blacks differ markedly in the proportion of the breakdown which occurs in each segment. But only the breakage of more difficultly disrupted structure is identified with chemical changes in the black and with concomitantly increased carbon—polymer interaction activity, i.e., with enhanced reinforcement. In studying the breakage of aggregate black structure which occurs when the blacks are milled in rubber, the following factors are considered: (1) Carbon Black Concentration: Breakage increases continuously, though not steadily, with carbon black concentration. This result is used to emphasize the merits of concentrated black masterbatching as the means for producing high quality products from SBR, BR, and EPDM rubbers. (2) Carbon Black Structure: Taking the total structure breakage over a broad range of carbon black concentrations, the extent of the breakage increases with the extent of the primary aggregate structure in the original black. (3) Polymer Viscosity or Molecular Weight: The extent to which breakage occurs on milling increases with the polymer viscosity or molecular weight. Since this result clearly cites the need for high shearing forces during milling, the severe limitations which must attend the use of plasticizing oils is implied. (4) Open Mill vs Banbury Mixing: The extent to which breakage occurs in the Banbury is significantly less than that on the two roll mill. Evidence is presented to show that this, clearly, is a temperature related result and, as in (3) above, that the magnitude of the shearing forces is the critical factor.

The Surface Tension of Rubber Solutions

1931 ◽  
Vol 4 (3) ◽  
pp. 354-360
Author(s):  
G. W. Shacklock
Keyword(s):  
Molecular Structure ◽  
Molecular Weight ◽  
Surface Tension ◽  
Benzene Solution ◽  
Rubber Particle ◽  
Mechanical Action ◽  
The Past ◽  
Pure Product ◽  
Simple Molecules ◽  
Improved Methods

Abstract During the past few years much attention has been paid to the constitution of raw rubber. The much improved methods of production of plantation rubber have resulted in a reasonably pure product available for investigation, and chemical analysis undoubtedly shows an empirical formula of C5H8 for the hydrocarbon. From this point onward, knowledge becomes less certain. Osmotic pressure and molecular weight measurements give no confirmation of a simple molecular structure, but show, in benzene solution, a behavior comparable with that of colloids. This is supported by experiments on swelling and viscosity, and by ultramicroscopic examination, all of which lead to the conclusion that rubber is a lyophilic colloid. Hence arose the concept that the rubber particle is a polymer of simple molecules of formula C5H8 (possibly isoprene), such a structure being in agreement with the production of rubber-like substances by the action of sodium upon isoprene and butadiene (Harries, Annalen, 395, 211 (1912)). The decrease in viscosity of a rubber solution with increasing periods of mastication of the rubber is hence regarded as a measure of depolymerization due to mechanical action; the increased ease of solution after mastication is confirmatory evidence.

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