Developing Natural Rubber Based Manufacturing Microenterprise Cluster in the State of Tripura

Abstract The latex and natural rubber from rubber trees [Hevea brasiliensis (Willd. exAdr. de Juss.) Muell. Arg.] from clones (RRIM 600, IAN 873, GT 1 and PB 252) recommended to the state of São Paulo, Brazil, were studied in three different tapping systems. The parameters studied were dry rubber content (DRC), percentages of ash and of nitrogen, Wallace Plasticity (P0) and Mooney Viscosity (VR). The rubber properties vary considerably as a function of clone type, tapping method and season of the year. DRC tends to decrease in the beginning of the dry, cold season (May and June), whereas both nitrogen % and ash % increase in the same period. A good linear correlation was obtained for P0 and VR. The highest P0 and VR were obtained for RRIM 600.

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Changes in the Specific Volume of Rubber during Elongation

Rubber Chemistry and Technology ◽

10.5254/1.3542302 ◽

1958 ◽

Vol 31 (3) ◽

pp. 513-518 ◽

Cited By ~ 1

Author(s):

A. B. Kusov ◽

V. I. Trofimova ◽

Yu I. Nilova

Keyword(s):

Natural Rubber ◽

Specific Volume ◽

The State ◽

Volume Versus ◽

Inflection Points

Abstract 1. It was shown that an increase in volume under strain, which reaches 2% at the maximum elongations, is observed in both loaded and unloaded stocks based on different rubbers. 2. The curves of specific volume versus elongation are characteristically S-shaped in the general case, and the inflection points of these curves correspond to the same elongations as do the inflection points in the curves of stress versus elongation. 3. Natural rubber stocks show a drop in volume, related to the crystallization of the rubber, until a certain elongation is reached ; the higher the state of cure, the higher this elongation.

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The Oil Resistance of Rubber. IV. Mechanism of the Oil Resistance of Neoprene

Rubber Chemistry and Technology ◽

10.5254/1.3538982 ◽

1937 ◽

Vol 10 (2) ◽

pp. 312-316

Author(s):

Shĭ Kambara

Keyword(s):

Dielectric Properties ◽

Natural Rubber ◽

Chain Length ◽

Complex Structure ◽

The State ◽

Oil Resistance ◽

High Polarization

Abstract To study the mechanism of the oil resistance of Neoprene, the following points were investigated. 1. The dielectric properties of Neoprene and its comparison with the crude and purified natural rubber. 2. The viscosity of benzene solutions of Neoprene and natural rubber of various concentrations. From data on the relation between polarization, the chain-length of solute and the concentration, the state of solutes in solution was discussed, and the oil resistance of Neoprene is explained on the basis of its high polarization and its complex structure. In conclusion, the author wishes to express his thanks to Professor Yoshio Tanaka for valuable suggestions and criticisms.

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Quantitative Characterization of Cure. II. Use of Modulus as a Measure of the State of Cure of Pure-Gum Natural-Rubber Vulcanizates

Rubber Chemistry and Technology ◽

10.5254/1.3543409 ◽

1952 ◽

Vol 25 (3) ◽

pp. 439-446 ◽

Cited By ~ 1

Author(s):

W. P. Fletcher ◽

Geoffrey Gee ◽

S. H. Morrell

Keyword(s):

Natural Rubber ◽

The State ◽

Quantitative Characterization ◽

Natural Rubber Vulcanizates ◽

Practical Disadvantage ◽

Practical Measure

Abstract The purpose of this investigation was to develop methods of measuring state of cure which involved only measurements normally available or very readily made. Swelling measurements, although suitable in theory, suffer the practical disadvantage of being time-consuming, but it is shown that they can be replaced very satisfactorily by modulus at 100 per cent elongation. This is a good practical measure of state of cure for most purposes, and simple corrections are developed which extend its range of usefulness. An easily constructed machine is described for the accurate measure of modulus at small elongations.

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The Elasticity of Rubber-Bitumen Binders for Use in Roads

Rubber Chemistry and Technology ◽

10.5254/1.3540337 ◽

1964 ◽

Vol 37 (2) ◽

pp. 457-476

Author(s):

Jacqueline de Merlier ◽

J. Leveque ◽

J. Curchod

Keyword(s):

Molecular Weight ◽

Natural Rubber ◽

Elastic Properties ◽

Elastic Recovery ◽

Test Methods ◽

The State ◽

The Other ◽

Polymer Analysis ◽

Rubber Blends ◽

The One

Abstract The authors have first described test methods used, on the one part, to determine, in a simple way, the elastic recovery of binders after deformation, and on the other, to characterize accurately the state of degradation of the rubber within the bitumen by assessing the molecular weight of the dispersed polymer. Analysis and interpretation of results have stressed: (a) the effect of the molecular weight of crude natural rubber on the elastic recovery of bitumen-rubber blends; (b) the effect of the way in which bitumen-crude natural rubber blends are prepared on their elastic properties and (c) the effect of the nature of synthetic elastomers on the elasticity of bitumen blends.

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Numerical natural rubber curing simulation, obtaining a controlled gradient of the state of cure in a thick-section part

10.1063/1.2729631 ◽

2007 ◽

Author(s):

A. El Labban ◽

P. Mousseau ◽

J. L. Bailleul ◽

R. Deterre

Keyword(s):

Natural Rubber ◽

The State ◽

Thick Section

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State of Cure of Neoprene Vulcanizates. Measurement by the T-50 Test

Rubber Chemistry and Technology ◽

10.5254/1.3543285 ◽

1947 ◽

Vol 20 (2) ◽

pp. 527-536

Author(s):

D. B. Forman ◽

R. R. Radcliff

Keyword(s):

Natural Rubber ◽

Physical Properties ◽

Production Control ◽

The State ◽

Chemical Analyses ◽

Chemical Effects ◽

Rubber Vulcanizate ◽

Natural Rubber Vulcanizates

Abstract Generally the physical properties of elastomer vulcanizates are considered to depend on their states of cure. Although many tests for measuring the state of cure have been developed, none are completely satisfactory. Some of them fail to distinguish between the physical or chemical effects of compounding ingredients, others are too laborious to be of practical value. The T-50 test developed by Gibbons, Gerke, and Tingey for natural rubber vulcanizates eliminates some of these difficulties and further reduces the number of tests required for production control. The T-50 test is based on the retraction of a stretched and frozen specimen with an increase in temperature. The temperature at which the sample retracts to 50 per cent of its initial frozen elongation is termed the T-50 value. From a physical standpoint the test is sensitive, precise, and easily performed. From a chemical standpoint the original workers as well as Vila showed that, for any specific natural rubber composition, the T-50 value correlates with the amount of combined sulfur. Since the state of cure of a rubber vulcanizate is frequently discussed in terms of combined sulfur, the T-50 test offers a correlation of the state of cure with combined sulfur without the necessity for involved chemical analyses.

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Peroxide vulcanization of natural rubber. Part II: effect of peroxides and co-agents

Journal of Polymer Engineering ◽

10.1515/polyeng-2014-0035 ◽

2015 ◽

Vol 35 (1) ◽

pp. 21-29 ◽

Cited By ~ 14

Author(s):

Ján Kruželák ◽

Richard Sýkora ◽

Ivan Hudec

Keyword(s):

Mechanical Properties ◽

Natural Rubber ◽

The State ◽

Rubber Matrix ◽

Cross Linking ◽

Type I ◽

Type Ii ◽

Rubber Compounds ◽

Rubber Part

Abstract Four types of peroxides in combination with two types of co-agents were used as cross-linking agents for the preparation of rubber compounds based on natural rubber. The effects of Type I and Type II co-agents on cross-linking and physical-mechanical properties of vulcanizates were investigated. The correlation between mechanisms of the interaction of co-agents with the rubber matrix in relation to the characteristics of tested systems was discussed. The results showed that the Type I co-agent influenced the rate and the state of cure. Physical-mechanical properties were improved by addition of the Type I co-agent. By contrast, the Type II co-agent had no contribution to the rate and state of cure. Moreover, physical-mechanical properties of vulcanizates deteriorated in the presence of this type of co-agent.

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