Tensile Strength Of Rubber Research Articles

Tensile strength of rubber described via the formation and rupture of load-bearing polymer chains.

A theoretical picture describing the tensile strength σ_{T} of elastomers is developed. σ_{T} is composed of three factors: (1) the tensile strength of individual polymer load-bearing chains (LBCs) according to Eyring's theory, (2) an occupation number of LBC states using Fermi statistics, and (3) an excluded volume factor reducing the number of possible LBCs due to the presence of filler particles or crosslinks between polymers. This description is compared to experimental tensile strengths of carbon black (N339)-filled EPDM (Keltan 4450) as well as to other experiments in the literature studying the effects of temperature, filler concentration, and particle size as well as crosslink density.

DISPERSION AND MECHANICAL PROPERTIES OF CERIUM OXIDE FILLED INTO RUBBER COMPOSITES

ABSTRACT Rubber composites were synthesized by natural rubber filled with cerium oxide with different particle diameters. The dispersion morphology of cerium oxide in rubber matrix and the mechanical properties of composites were studied, and the contrast experiment of reinforcing rubber with cerium oxide was performed. The results showed that the small particles of cerium oxide had better disparity than the large particles of cerium oxide in NR. The mechanical properties of rubber filled with small particles of cerium oxide were better than those of rubber filled with large particles of cerium oxide. The crystalline rubber was measured by X-ray diffraction, which indicated that the CeO2 accelerated crystallization capacity and confined the rubber chain movement. The tensile strength of rubber was increased by this confinement.

Delaminations in Resin-EPDM Monomer Bondlines as a Result of Solvent Exposure and Adhesive-Induced Phenolic Resin Disproportionation Reactions

Delaminations in aluminum-to-phenolic resin-cured ethylene-propylene-diene monomer (EPDM) rubber bondlines were studied by a variety of techniques, including surface chemical analysis, microscopy, gas chromatography/mass spectrometry (GC/MS), pyrolysis gas chromatography/mass spectrometry (PyGC/MS), and analysis of solvent extracts from the failures by high performance liquid chromatography/mass spectrometry (HPLC/MS). The rubber was bonded to the aluminum using a common, commercially available metal primer and rubber-to-metal adhesive. The locus of failure was cohesive in a thin layer of rubber near the rubber/adhesive interface. Two chemical contributing factors to the debonding were found. One was the use of a cleaning solvent (d-limonene) that reacts with rubber and competes with normal cross-linking. Another was an incompatibility with the rubber-to-metal adhesive that causes disproportionation and breakdown of the phenolic resin. Both mechanisms are expected to cause a lowered cross-link density and reduce rubber tensile strength, leading to weakened rubber near the rubber/adhesive interface.

Study on Physics Properties of ESPCP Stator Rubber with Oil Erosion

For studying physical properties of Nitrile Butadiene Rubber(NBR) stator of Electrical Submersible-motor-driven Progressive Cavity Pumping (ESPCP) with oil erosion, two different formulations of NBR soaked in crude oil at 90 °C for 168h. Variation rule with time of rubber quality, hardness, volume, tensile strength and elongation rate are got. The results show that erosion in the same temperature, rubber quality increase rapidly in the first 24h, increase slowly down in 24~168h. Rubber hardness does not change significantly soaked within 168h. Rubber volume change obviously in the first 72h and change slowly in 72~168h. In the first 96h, the rubber's tensile strength and elongation rate change quickly, slowly changes in 96~168h. The study has a certain reference of design of ESPCP stator under certain operating conditions.

The Effect of Accelerators on Curing Characteristics and Properties of Natural Rubber/Chlorosulphonated Polyethylene Rubber Blend

The aim of this work was to determine the influence of accelerator type on curing behavior and properties of sulphur vulcanized rubber blend based on natural rubber (NR) and chlorosulphonated polyethylene (CSM). In NR/CSM compounds filled with carbon black three types of accelerator were used: N-cyclohexylbenzothiazylsulphenamide (CBS), tetramethylthiuram disulphide (TMTD), and 2-mercaptobenzothiazol (MBT). The curing characteristics were estimated using oscillating disk rheometer. The results revealed that the accelerator type not only affects the cure characteristics, but also has great influence on the mechanical properties of obtained elastomers. It was determined that the tensile strength of rubber blends cured in the presence of TMTD was relatively high.

Modyfikacja kauczuku butadienowo-styrenowego polimetylosiloksanami. Cz. II. Uklady napelnione krzemionka

The effects of several modifiers, from the group of polymethylhydrosiloxanes (PMHS, Table 1), on the morphology and selected properties of styrene-butadiene rubber (SBR) vulcanizates filled with silica (Table 2) were studied. The kinetics of rubber crosslinking changes as a result of blocking of active centers on the silica surface by the particles of reactive modifier (Table 3). Crosslinking density of vulcanizate increases with an increase in reactivity of modifier used, expressed as a ratio of the amounts of methylhydrosiloxane mers (DH) and dimethylsiloxane ones (D) in its particle (Table 4). The results of investigations of degree of filler dispersion in the rubber matrix (Fig. 1 a-e) correspond with the results of an estimation of vulcanizates’ mechanical characteristics (Table 5). Namely, better silica dispersion causes clear increase in rubber tensile strength with just slight decrease in relative elongation at break. So PMHS investigated play a double role in the filled SBR as dispersants and crosslinking co-agents. Migration of modifiers to the rubber surface, causing decrease in friction factor (Fig. 2), was also found. This effect is the greater the lower reactivity of modifier used. An interpretation of this phenomenon is presented.

Adequacy of the tensile/elongation test as a quality control criterion for vehicle tires

Most tire failures in Saudi Arabia result in severe vehicle crashes. Tire failures, such as tread separation and blowouts, are the most notable events that occur on a daily basis. This paper deals with the elongation and tensile strength of the tire rubber as quality control criteria in evaluating vehicle tires. Specimens from six different tire brands were subjected to laboratory tests to investigate the tensile strength and elongation of the tire rubber. The laboratory results and the statistical field survey data were compared to determine the possibility of using the tensile strength of rubber as a quality control criterion. The thermal oxidative durability of the investigated tires during aging were also estimated through the loss in their strength.

The effect of a low‐viscosity swelling liquid on the tensile strength of rubber

AbstractThe paper examines the effect of swelling on a number of different gum rubbers and rubbers filled with different types and concentrations of black. The observed decrease in strength with decreasing rubber fraction Vr (increasing swelling ratio) is, in the case of gum rubbers, associated with a decrease in internal friction. The incorporation of a black filler is shown to increase strength by hydrodynamic stiffening and by an increase in internal friction of the rubber network, and a simple reduction scheme of the data shows a close analogy between the strength as a function of Vr and the dynamic modulus of a rubber solution as a function of concentration. The results lead to a failure criterion, which describes the energy density at break as a simple function of the hysteresis near break.

The Tensile Strength of Rubber and Rubber Molecule

Abstract The tensile strengths of crystallized crude rubber and vulcanized rubber are remarkably different from each other at room temperature, but are found to be almost the same at the temperature of liquid air. By assuming that the tensile strength of crystallized rubber at this low temperature is entirely due to its chain molecules, the forced needed to break a chain molecule of rubber at its weakest point is estimated.

Impact Machine for Rubber Testing. Determining the Stress-Strain Diagram at High Speed

Abstract IN CONTRAST to the ordinary standard procedure at low speed, various methods have been devised to carry out tensile tests of rubber under rapid application of load, with the purpose of securing more definite indications, at a speed in agreement with actual performance. The application of those methods to the study of the tensile properties of rubber stocks goes as far back as 1910, when Beadle and Stevens (1) made use of the pendulum to investigate these properties. Their work applied to rubber compounds of different compositions and different loadings. More recently, Van Rossem and Beverdam (2) presented a set of results tending to prove an optimum in the tensile properties, coinciding with the best cure as determined by practical observation. However, all experiments, previous to those here reported, are limited to the determination of the tensile strength of rubber, and no attempt was made to extend the investigations to the determination of the resistance of rubber at different elongations. The machine here illustrated is designed to measure not only the energy absorbed at break, under conditions of high speed, by impact, but also the stress-strain relation.

Hardness of Vulcanized Rubber at Low Temperatures

Abstract 1. By means of a new apparatus which is described, it is possible to estimate the hardness of vulcanized rubber at low temperatures. 2. The hardness of rubber-sulfur vulcanizates increases hyperbolically with lowering of temperature and they become “frozen” and hard at −50° C. 3. Since ordinary softening agents having high viscosities solidify at −30° to −40° C., these are unsuitable for softening rubber to be exposed to temperatures below this range. 4. Softening agents which do not solidify at −50° C. are among those ordinarily used as solvents, and they have very low viscosities. Though their effect on the hardness of rubber at −50° C. is small when they are used in small percentages, they prevent the freezing of rubber at −50° C. when large proportions are used. They are, however, of no practical value, since they decrease the tensile strength of rubber. 5. Vulcanized rubber containing 30 per cent of reclaimed rubber also froze to a hard product at −50° C. 6. The relation between temperature and hardness of rubber vulcanized with organic accelerators is the same as that in the case of rubber vulcanized with sulfur alone.