Rubber tensile properties

Anorin-38 has also shown an interesting effect as a multifunctional additive (a single additive to replace many of the conventional additives) for natural rubber (NR). It showed excellent blending behavior and compatibility with NR. Aorin-38 enhances the tensile properties and percent elongation, decreases fatigue, acts as an antioxidant and antiozonant, and positively affects many of the other properties, apart from acting as a process aid and a cure enhancer [183-186]. 

They have studied the properties of NR-epoxidized natural rubber (ENR) blend nanocomposites also. Vulcanization kinetics of natural mbber-based nanocomposite was also smdied. The effect of different nanoclays on the properties of NR-based nanocomposite was studied. The tensile properties of different nanocomposites are shown in Figure 2.7 [33]. 

Jha A. and Bhowmick A.K., Thermoplastic elastomeric blends of poly(ethyleneterephthalate) and carylate rubber 1. Influence of interaction on thermal, dynamic mechanical and tensile properties. Polymer, 38, 4337, 1997. 

Speckhard T.A. and Cooper S.L., Ultimate tensile properties of segmented pol3furethane elastomers Factors leading to reduced properties for pol3mrethane based on nonpolar soft segments. Rubber Chem. TechnoL, 59, 405, 1986. 

Mechanics of Generation of Great Tensile Properties IN Carbon-Filled Rubber... 

Finally, from stress-stress experiments it was found that the Young s modulus increases from 1.93 MPa to 27.24 MPa with the addition of 10 phr clay along with 10 phr stearic acid. However, it is evident from Fig. 43b that the improvement of tensile properties is not as high as expected from other studies. Insufficient cross-linking of the rubber matrix could be the reason behind this observation. 

For both EPDM-LDH and XNBR-LDH nanocomposites, the various tensile properties are summarized in Table 13 and their typical stress-strain plots are shown in Fig. 58 [104]. In Fig. 58a, the gum vulcanizates of both rubber systems showed typical NR-like stress-strain behavior with a sharp upturn in the stress-strain plot after an apparent plateau region, indicating strain-induced crystallization. With the addition of LDH-C10 in the XNBR matrix, the stress value at all strains increased significantly, indicating that the matrix undergoes further curing (Fig. 58b). 

Fig. 11 Effect of on tensile properties for PCL/PPO blends containing 60% of PCL (numbers indicate rubber particle size arrows indicate the respective properties)...

As a result, the positive effect of the particle size reduction on the tensile properties seems to be counteracted by the negative effect of the rubber connectivity. 

An important feature of filled elastomers is the stress softening whereby an elastomer exhibits lower tensile properties at extensions less than those previously applied. As a result of this effect, a hysteresis loop on the stress-strain curve is observed. This effect is irreversible it is not connected with relaxation processes but the internal structure changes during stress softening. The reinforcement results from the polymer-filler interaction which include both physical and chemical bonds. Thus, deforma-tional properties and strength of filled rubbers are closely connected with the polymer-particle interactions and the ability of these bonds to become reformed under stress. 

Natural rubber exhibits unique physical and chemical properties. Rubbers stress-strain behavior exhibits the Mullins effect and the Payne effect. It strain crystallizes. Under repeated tensile strain, many filler reinforced rubbers exhibit a reduction in stress after the initial extension, and this is the so-called Mullins Effect which is technically understood as stress decay or relaxation. The phenomenon is named after the British rubber scientist Leonard Mullins, working at MBL Group in Leyland, and can be applied for many purposes as an instantaneous and irreversible softening of the stress-strain curve that occurs whenever the load increases beyond... 

Standard methods for determining tensile properties of rubbers have evolved gradually and are now in a well-defined state. Essentially, dumbbell shaped, or less often ring, test pieces are strained at a constant rate of traverse and force and corresponding extension recorded. The force readings are expressed as stresses by reference to the original cross-sectional area of the test piece. 

The standardised test procedures are concerned with the resistance of the rubber to the liquid, not the estimation of degree of cure, and generally recommend the measurement of change in dimensions, tensile properties and... 

Amines as Antioxidants or Antiozonants for Rubber (13). Oxidative degradation of vulcanized rubber is evaluated from the depression in the tensile properties during aging in the Geer oven. 

Reactivities of Amines in Homogeneous Systems (14, 17). The decrease in the tensile properties of the vulcanized rubber during aging may be attributed to the degradation of the rubber molecule by oxidation. This may be supported by the experimental result in the oxidation of rubber solution. 

Tensile properties of these two EPDM rubbers are fairly representative of what can be obtained using commercial polymers having a 125° C Mooney viscosity near 55. Tensile strengths as high as 2900 psi have... 

Standard testing for tensile properties of plastics Standard testing for tensile properties of rubbers... 

Du et al. (50) reported the synthesis of butadiene styrene rubber nanocomposites with halloysite nanotubes. The tensile properties of the composites containing various amounts of nanotubes are depicted in Table 2.2. The tensile properties were observed to significantly increase as a function of increasing amount of nanotubes in the composites. For the maximum loading of the nanotubes, a tensile modulus of 5.56 MPa was observed as compared to 1.52 MPa for the pure polymer. 

The micromechanical deformation behavior of SAN copolymers and rubber-reinforced SAN copolymers have been examined in both compression [102] and in tension [103,104]. Both modes are important, as the geometry of the part in a given application and the nature of the deformation can create either stress state. However, the tensile mode is often viewed as more critical since these materials are more brittle in tension. The tensile properties also depend on temperature as illustrated in Figure 13.6 for a typical SAN copolymer [27]. This resin transforms from a brittle to ductile material under a tensile load between 40 and 60 C. 

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