NMR Study of Vulcanized Rubber

1971 ◽  
Vol 44 (5) ◽  
pp. 1273-1277 ◽  
Author(s):  
Shizuro Fujiwara ◽  
Kunihiko Fujimoto
Keyword(s):  
Carbon Black ◽  
Crosslink Density ◽  
Average Distance ◽  
Inhomogeneous Structure ◽  
Rubber Layer ◽  
Vulcanized Rubber ◽  
Filled Rubber ◽  
Nmr Study ◽  
Rubber Phase

Abstract It is shown that NMR-linewidth measurements are useful to obtain information about the crosslink density and the average distance between the crosslinks in vulcanized rubber. Inhomogeneous structure of the rubber phase in carbon black-filled rubber is evidence and the thickness of the rubber layer on carbon black is estimated at 50 A˚.

States of Carbon Black Dispersion and Extensibility of Rubbers

1993 ◽  
Vol 66 (2) ◽  
pp. 317-328 ◽  
Author(s):  
Asahiro Ahagon
Keyword(s):  
Carbon Black ◽  
Tensile Property ◽  
Crosslink Density ◽  
Hydrodynamic Effect ◽  
Property Variation ◽  
Agglomerate Size ◽  
Filled Rubber ◽  
Two Temperatures ◽  
Confined Polymer ◽  
Carbon Black Dispersion

Abstract Analysis is made for the origin of the mixing-induced tensile property variation of a filled rubber. Attention is paid to the hydrodynamic effect f(ϕe) of the filler, defined here as the factor to adjust the deviation of 100% modulus from the theory of rubber elasticity. For the rubbers mixed under variety of conditions, the f(ϕe)'s are calculated from the observed values of the modulus, at 25°C and 100°C, and the crosslink density. The variation of the f(ϕe) is considered to be governed by the mobility of the polymer confined in agglomerates of the filler. The mobility variation due to mixing seems to be mainly influenced by agglomerate size at 25°C, and by agglomerate size and chemical constraints at 100°C. Therefore, the f(ϕe)'s at the two temperatures are suggested to be useful measures of the state of carbon-black micro-dispersion. The extensibility of the rubbers is closely related f(ϕe). This indicates that the failure property is also governed by the mobility of the confined polymer.

Effect of Crosslink Density on Cut Growth in Black-Filled Natural Rubber Vulcanizates

2002 ◽  
Vol 75 (5) ◽  
pp. 935-942 ◽  
Author(s):  
G. R. Hamed ◽  
N. Rattanasom
Keyword(s):  
Carbon Black ◽  
Natural Rubber ◽  
Crack Growth ◽  
Crosslink Density ◽  
Longitudinal Crack ◽  
Test Pieces ◽  
Filled Rubber ◽  
Longitudinal Cracks ◽  
Natural Rubber Vulcanizates ◽  
High Crosslink Density

Abstract Tensile strengths, σb, of gum and N115-filled natural rubber test pieces, with and without edge pre-cuts, have been determined. At low crosslink density, the regular (uncut) σb of filled and gum vulcanizates is similar. However, at high crosslink density, the gum NR becomes brittle, while the corresponding filled rubber remains strong and resistant to cut growth. It is proposed that the tightly linked gum does not strain-crystallize appreciably during stretching, but that its filled counterpart does. Carbon black appears capable of inducing crystallization in a network that alone remains amorphous during extension. Filled vulcanizates of various crosslink densities have similar normal tensile strengths ( ≈ 30 MPa), but strengths differ, sometimes more than twofold, if a pre-cut is present. Lightly crosslinked specimens containing a small cut have strengths that depend very weakly on cut size, c. Furthermore, these develop long longitudinal cracks from which catastrophic rupture initiates. With larger cuts, strength decreases more rapidly with increasing c, there is less longitudinal crack growth, and rupture initiates near the original cut tip. In contrast, the strength of a highly crosslinked vulcanizate is sensitive to small cuts and test pieces exhibit minimal longitudinal cracking before failure.

Effect of Compound Ingredients on Adhesion between Rubber and Brass-Plated Steel Cord

2005 ◽  
Vol 78 (2) ◽  
pp. 175-187 ◽  
Author(s):  
Takeshi Hotaka ◽  
Yasuhiro Ishikawa ◽  
Kunio Mori
Keyword(s):  
Carbon Black ◽  
Physical Properties ◽  
Adhesive Strength ◽  
Crosslink Density ◽  
Condensation Reaction ◽  
Gel Formation ◽  
Vulcanized Rubber ◽  
Sulfur Vulcanization ◽  
Steel Cord ◽  
Carbon Gel

Abstract Effect of several ingredients in the rubber on adhesion characteristics between brass-plated steel cord and rubber was thoroughly investigated. Amine component is generated by N,N'-dicyclohexylbenzothiazole-sulphenamide- (DCBS) accelerated sulfur vulcanization, and it is known to promote stress-induced corrosion crack in the brass layer at the brass plated steel cord. Hexamethoxymethylmelamine (HMMM), which is formulated for the condensation reaction of RF resin, has a function to trap amines, which was found to effectively improve the adhesive strength in water-aged degradation. It was clarified that the physical properties of the vulcanized rubber such as crosslink density and strain modulus are also improved by trapping the residual amine accompanying improved adhesive strength for the formulation with HMMM. Influence of carbon black on concentration of the residual amine and adhesive strength was also studied. Amount of the amine was inversely proportional to the carbon gel content, while adhesive strength linearly increased with the level of carbon gel. It was assumed that the carbon black dose enhances the adhesive strength due to a preferential entrapment of the amine at the stage of carbon gel formation.

Rubber—Black Interaction Influence on Cure Level of Vulcanizates

1972 ◽  
Vol 45 (1) ◽  
pp. 94-105 ◽  
Author(s):  
J. J. Brennan ◽  
D. H. Lambert
Keyword(s):  
Carbon Black ◽  
Induction Period ◽  
Crosslink Density ◽  
Total Concentration ◽  
Molar Concentration ◽  
Bound Rubber ◽  
Cure Time ◽  
Rubber Phase ◽  
Black Level

Abstract The crosslink density of vulcanizates has been quantitatively investigated using swelling measurements (Vr) of compounds of cis-1,4-polybutadiene reinforced with N242, N326, or N990 (Vulcan 6H, Regal 300, Sterling MT). Crosslink density in both filled and unfilled stocks is shown to be related to the molar concentration of the curatives in the unbound rubber phase of the vulcanizates and not merely to total concentration. The effects of different carbon black loadings and of cure time are demonstrated to be fully describable by the extent of carbon black—rubber interaction, measured by bound rubber; that occurs during mixing and during the induction period of the cure step. Greater rubber-black interaction, whether achieved by higher black level or from higher reinforcing blacks, always yielded vulcanizates of increased crosslink density compared to an identically vulcanized gum control. Calculating curative concentration on the basis of unbound rubber—rather than total rubber—illustrated the expected dependence of crosslink density upon curative concentration and graphically explains the presence of so-called “excess” crosslinks. Implied, also, is one cause for the “scorchy” character of highly reinforcing blacks and the higher modulus obtained with these blacks.

Reactions of Radicals in Filled Rubber Compounds: II. Generation and Subsequent Reactions of Radicals Upon Deformation

2005 ◽  
Vol 78 (4) ◽  
pp. 659-673 ◽  
Author(s):  
Makoto Kawakubo ◽  
Katsunori Tsunoda ◽  
Hirofumi Yajima ◽  
Tadahiro Ishii ◽  
Hiroyuki Kaidou ◽  
...  
Keyword(s):  
Carbon Black ◽  
Crosslink Density ◽  
Bulk Property ◽  
Density Measurements ◽  
First Order ◽  
Filled Rubber ◽  
Rubber Compounds ◽  
Bond Scission ◽  
Radical Generation ◽  
Simple Combination

Abstract Effect of stretching on oxidative crosslinking of a carbon black filled IR vulcanizate at a normal temperature was studied by means of ESR and crosslink density measurements. Upon deformation, ESR intensity increased and crosslink density decreased, indicating scission of load supporting bonds generating free radicals. Bond scission increased with increasing strain. Resting after deformation, the ESR intensity decayed steadily following simple combination of first order and second order kinetics. The decay was overwhelmingly caused by first order reactions, which were considered to be irrelevant to crosslinking. On the other hand, crosslink density increased during resting. The results strongly suggested that ESR observed the radicals at the surface of the carbon black filled rubber, while crosslink density evaluated the bulk property. The crosslink density increase during resting outweighed the reduction due to deformation. Deformation accompanied by radical generation apparently accelerated oxidative crosslinking.

DISCUSSION ABOUT THERMAL CONDUCTIVITY OF CARBON BLACK FILLED RUBBER

2015 ◽  
Vol 6 (2) ◽  
pp. 159-172 ◽  
Author(s):  
Junping Song ◽  
Lianxiang Ma ◽  
Yan He ◽  
Wei Li ◽  
Shi-Chune Yao
Keyword(s):  
Thermal Conductivity ◽  
Carbon Black ◽  
Filled Rubber

Studies on dynamic creep of carbon black-filled rubber vulcanizates.

1989 ◽  
Vol 62 (7) ◽  
pp. 448-458
Author(s):  
Kunihiko FUJIMOTO ◽  
Tatsuhiko HATAKEYAMA
Keyword(s):  
Carbon Black ◽  
Filled Rubber ◽  
Dynamic Creep

STUDY ON NANOMORPHOLOGY OF HIGH-STRUCTURE CARBON BLACK AND ITS BOUND RUBBER BY AFM

2012 ◽  
Vol 19 (01) ◽  
pp. 1250003
Author(s):  
JIAN CHEN ◽  
YONGZHONG JIN ◽  
JINGYU ZHANG ◽  
YAFENG WU ◽  
CHUNCAI MENG
Keyword(s):  
Carbon Black ◽  
Cluster Structure ◽  
Chemical Activity ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Atomic Force ◽  
Filled Rubber ◽  
Bound Rubber ◽  
Styrene Butadiene ◽  
High Structure

Bound rubber in carbon black (CB) filled rubber (natural rubber (NR) and styrene–butadiene rubber (SBS)) was prepared by the solvent method. The nanomorphology of CB and rubber/CB soluble rubber was observed by atomic force microscope. The results show that high-structure CB DZ13 has a "grape cluster" structure which consists of many original particles with the grain size of about 30–50 nm. Graphitizing process of CB decreases the amount of bound rubber. The NR/DZ13 soluble rubber with island–rim structure has been obtained, where the islands are DZ13 particles and the rims around the islands are occupied by NR film. But when the graphitized DZ13 particles were used as fillers of rubber, we have only observed that some graphitized DZ13 particles were deposited on the surface of the globular-like NR molecular chains, instead of the spreading of NR molecular chains along the surface of DZ13 particles, indicating that graphitized DZ13 has lower chemical activity than ungraphitized DZ13. Especially, we have already observed an interesting unusual bound rubber phenomenon, the blocked "bracelet" structure with the diameter of about 600 nm in which CB particles were blocked in ring-shaped SBS monomer.

Carbon Black. I—A Study of Its Volatile Constituents

1928 ◽  
Vol 1 (3) ◽  
pp. 485-497 ◽  
Author(s):  
C. R. Johnson
Keyword(s):  
Carbon Black ◽  
Volatile Matter ◽  
Original Sample ◽  
Missing Information ◽  
Volatile Constituents ◽  
Vulcanized Rubber ◽  
Rates Of Evolution ◽  
Temperature And Pressure ◽  
The Relationship

Abstract The rates of evolution of gas from carbon black with variation of time, temperature, and pressure have been determined. Complete analyses have been made of five types of carbon black, which involve an organic combustion of the original sample, an organic combustion of the sample after the gases have been removed, a determination of the loss in weight represented by the gases removed, analyses of the gases removed, and finally a complete accounting, or balance, of the carbon in the steps considered. In an attempt to supply some missing information not revealed by the foregoing, some special gas analyses under varying conditions were made. The relationship between the amount and composition of volatile matter evolved from carbon blacks and the properties imparted to vulcanized rubber when compounded with these blacks has been studied.

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