Volume change and gas transport at uniaxial deformation of filled natural rubber

1987 ◽  
Vol 22 (10) ◽  
pp. 3470-3476 ◽  
Author(s):  
W. F. Reichert ◽  
M. K. Hopfenm�ller ◽  
D. G�ritz
Keyword(s):  
Natural Rubber ◽  
Volume Change ◽  
Gas Transport ◽  
Uniaxial Deformation

Heats of Reaction of Natural Rubber with Sulfur

1970 ◽  
Vol 43 (6) ◽  
pp. 1275-1293 ◽  
Author(s):  
N. Bekkedahl ◽  
J. J. Weeks
Keyword(s):  
Hydrogen Sulfide ◽  
Standard Deviation ◽  
Natural Rubber ◽  
Volume Change ◽  
Side Reaction ◽  
Enthalpy Change ◽  
Heat Of Reaction ◽  
Use Of Data ◽  
Heats Of Reaction

Abstract An adiabatic copper calorimeter was used to determine the heats of vulcanization of pale crepe natural rubber with sulfur for mixtures varying in composition from 0 to 32 per cent added sulfur. The side reaction that produces hydrogen sulfide was avoided by using reaction temperatures near 155° C. Heats of reaction at 25° C and at 155° C are reported. The enthalpy change at 25° C for compounds containing up to about 18 per cent sulfur is given in joules per gram of vulcanizate by the equation, ΔH25=−21.1·S with a standard deviation of 11 J/g. Here S is the percentage of combined sulfur. Above 18 per cent sulfur the heat of reaction at 25° C remains approximately constant at 380 ± 8 J/g. A comparison is made between the heat of vulcanization and the volume change on vulcanization, both as functions of combined sulfur, by making use of data in the literature.

Strain-Induced Crystallization of Natural Rubber: Effect of Proteins and Phospholipids

2008 ◽  
Vol 81 (5) ◽  
pp. 753-766 ◽  
Author(s):  
Sureerut Amnuaypornsri ◽  
Jitladda Sakdapipanich ◽  
Shigeyuki Toki ◽  
Benjamin S. Hsiao ◽  
Naoya Ichikawa ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Decomposition Methods ◽  
Uniaxial Deformation ◽  
X Ray Diffraction ◽  
High Mechanical Property ◽  
Naturally Occurring ◽  
Stress Strain Relation ◽  
Strain Induced Crystallization ◽  
Induced Crystallization

Abstract The effects of proteins and phospholipids in natural rubber (NR) on the strain-induced crystallization behavior during uniaxial deformation were studied by in-situ synchrotron wide-angle X-ray diffraction (WAXD) technique and simultaneous measurements of stress-strain relation. The influences of proteins and phospholipids in NR were evaluated separately by decomposition methods using deproteinization and lipase treatment, respectively. It was found that both components form a naturally occurring network, which is responsible for the strain-induced crystallizability of unvulcanized NR and the corresponding high mechanical property. This network also plays a significant role in strain-induced crystallization of vulcanized natural rubber.

The Synergistic Effect of Natural Rubber on the Crystallization of Lithium Poly(Isoprene)S (Coral Rubber)

1972 ◽  
Vol 45 (5) ◽  
pp. 1303-1314 ◽  
Author(s):  
M. J. Brock ◽  
Marjorie J. Hackathorn
Keyword(s):  
Synergistic Effect ◽  
Natural Rubber ◽  
Silver Nitrate ◽  
Induction Period ◽  
Volume Change ◽  
Crystallization Rate ◽  
Similar Species ◽  
Retarding Effect ◽  
Seeding Effect ◽  
Crystallizable Polymer

Abstract The influence of silver nitrate on the crystallization of poly(isoprene)s has been demonstrated as well as the synergistic effect of natural rubber on the crystallization of lithium catalyzed poly(isoprene). This synergism does not appear to be a “seeding” effect in the strictly definitive sense, since no seed crystals are actually added. In this case a better description of this effect might be cocrystallization where nucleation is promoted by the addition of a quantity of a highly regular similar species. Actually there is a good probability that the nucleating crystals themselves contain segments of the synthetic poly(isoprene). This conclusion is supported by the data shown in Figure 6 for a 50/50 mixture of natural rubber and a noncrystallizable Alfin polymer. The dilato meter curve for this mixture indicates that the 50 per cent non-crystallizable polymer has a slight retarding effect on the induction period for the crystallization of the natural rubber but the crystallization rate of the natural rubber in the 50/50 mixture is quite rapid up to the total volume change expected for natural rubber portion of the mixture. However, in the presence of 50 per cent of a crystallizable lithium poly(isoprene) (also shown in Figure 6), the crystallization rate of this mixture is much slower due to co crystallization. The proposed change from head-tail cis-1,4 addition to tail-head cis-4,1 addition whenever a 3,4 unit is introduced into the polymer chain seems to explain the experimental crystallinity data obtained in these studies. In addition, it raises some questions about the polymerization mechanisms involved and resulting from the orientation of a 3,4 unit being added to the growing end of a polydienyl chain.

Volume Changes in the Stretching of Vulcanized Natural Rubber

1951 ◽  
Vol 24 (4) ◽  
pp. 767-772 ◽  
Author(s):  
Geoffrey Gee ◽  
Jan Stern ◽  
L. R. G. Treloar
Keyword(s):  
Tensile Stress ◽  
Natural Rubber ◽  
Volume Change ◽  
Isotropic Material ◽  
Volume Changes ◽  
Change Mechanism ◽  
Hydrostatic Component

Abstract Measurements are presented of the volume changes accompanying small (≯100%) elongations of vulcanized natural rubber completely free from undissolved particles. The small expansions found agree with those calculated from the known compressibility of rubber and the hydrostatic component of the stretching force. It is pointed out that this volume change mechanism applies generally to any isotropic material, and does not contribute significantly (in rubber) to the tensile stress.

New Insights into Structural Development in Natural Rubber during Uniaxial Deformation by In Situ Synchrotron X-ray Diffraction

2002 ◽  
Vol 35 (17) ◽  
pp. 6578-6584 ◽  
Author(s):  
Shigeyuki Toki ◽  
Igors Sics ◽  
Shaofeng Ran ◽  
Lizui Liu ◽  
Benjamin S. Hsiao ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Structural Development ◽  
Uniaxial Deformation ◽  
X Ray Diffraction ◽  
X Ray

Structural evolution during uniaxial deformation of natural rubber reinforced with nano-alumina

2010 ◽  
Vol 22 (12) ◽  
pp. 2001-2008 ◽  
Author(s):  
Yijing Nie ◽  
Guangsu Huang ◽  
Liangliang Qu ◽  
Peng Zhang ◽  
Gengsheng Weng ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Structural Evolution ◽  
Uniaxial Deformation ◽  
Nano Alumina
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