Rubber formulation Tensile strength

Tensile strengths of chlorosulfonated polyethylene rubber (CSM) vulcanisates are around 3.5 MPa, depending upon formulation. In resilience, the elastomer compares favourably with other synthetic elastomers, though generally its resilience is lower than NR vulcanisates. Flex and abrasion resistance are very good and CSM will not support combustion. 

The cured polymers are hard, clear, and glassy thermoplastic resins with high tensile strengths. The polymers, because of their highly polar structure, exhibit excellent adhesion to a wide variety of substrate combinations. They tend to be somewhat britde and have only low to moderate impact and peel strengths. The addition of fillers such as poly (methyl methacrylate) (PMMA) reduces the brittleness somewhat. Newer formulations are now available that contain dissolved elastomeric materials of various types. These rubber-modified products have been found to offer adhesive bonds of considerably improved toughness (3,4). 

The cured properties of UV-aerobic acrylics include high tensile strengths, heat resistance, impact strength, and other properties expected of aerobic acrylics. Formulations have been developed with properties ranging from hard, tough adhesives with a Shore-D hardness of 80 to soft, elastomeric materials with a Shore-A of 10, similar to silicone rubber. 

Styrenic TPEs have strength properties equal to vulcanized rubber, but they do not require vulcanization. Properties are determined by polymer type and formulation. There is a wide latitude in compounding to meet a wide variety of application properties. According to application-driven formulations, Kratons are compounded with a hardness range from Shore A 28 to 95 (Shore A 95 is approximately equal to Shore D 40), sp gr from 0.90 to 1.18, tensile strengths from 150 to 5000 Ib/in (1.03 to 34.4 MPa), and flexibility down to 112°F (-80 C) (see Table 3.1).2... 

Compared with similar natural rubber compositions of the same hardness, styrene butadiene rubber (SBR) formulations are characterized by lower tensile strength, elongation, and resilience, lower resistance to tear, flexing, abrasion, ozone, and sunlight, and higher permanent set. The freeze resistance and permeability to gases of styrene butadiene are equivalent to those of comparable natural rubber, and so are the electrical characteristics. 

Crystallization. Some elastomers crystallize at temperatures that can significantly impact processing and vulcanizate behavior. Thus it is necessary to account for these behaviors when developing rubber compound formulations and processes. Crystallization is manifested by stiffening and hardening of the raw polymer, uncured compounded polymer, and the vulcanized polymer. Elastomers that crystallize will do so on stretching and thereby exhibit increased tensile strength. Those elastomers (eg polychloroprene and natural rubber) will... 

Cured silicone LIM rubber can be fabricated with physical properties equivalent to heat-cured rubber (500). Shore A hardness can range from 30 to 70, depending on formulations. Typical physical properties include tensile strengths as high as 9.7 MPa (1400 psi), elongations at break of 500-775%, and tear strengths... 

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