Tensile strength data, with reinforcement

The most commonly reported physical properties of radiation cross-linked natural rubber and compounds made from it are modulus and tensile strength, obtained from stress-strain measurements. Figure 5.6 illustrates some of the results obtained from gum rubber and from a natural rubber compound reinforced by HAF carbon black.143 In Figure 5.7, the tensile strength of radiation-cured gum is compared with vulca-nizates cured by sulfur and by peroxide.144 Selected tensile strength data from radiation-cured NR compounds are in Table 5.4. 

Figure 10.25. Tensile strength data for Kraton 101 (SBS triblock polymer) ( ) compared with those for an SBR vulcanizate containing 25% by volume of 350-A polystyrene latex spheres (O) (Morton and Healy, 1968) and SBR vulcanizate reinforced with 30% by weight HAF carbon black filler ( ). (Morton and Healy, 1968 Smith, 1970.)...

Upon analyzing the data of Table 10.1, it was observed that the tensile strength of composites reinforced with fibers modified by mercerization increased compared to pure HOPE and the other composites. However, an increase in the strength of composites occurred when compared to the pure matrix. 

Oriented films are available that have been stretched in the machine direction. The uniaxial orientation has some reinforcement effect on the film in the transverse direction. Tables 6.28 through 6.30 give the characteristics and properties of these PFA and ETFE films, which are available in one or two side adherable, and dimensionally stabihzed (by heat) grades. A comparison of tensile strength data from Tables 6.26 and 6.27 with those in Table 6.30 provides an appreciation for the impact of PFA and ETFE film orientation. 

Young s modulus of the block copolymer fibers compared favorably with that of the physical blends as shown in Table 6, and in general they follow the linear rule of mixtures. The modulus data suggested that one does not need very large PBZT molecules to have the reinforcing efficiency. From the tensile data, one clear trend is that the tensile strength of the block copolymer system is much... 

Effect of Molecular Configuration of Elastomer. The extent of the impact and strength improvements of ERL-4221 depends on the chemical structure and composition of the elastomer modifier. The data shown in Table I indicate that the carboxyl terminated 80-20 butadiene-acrylonitrile copolymer (CTBN) is the most effective toughening and reinforcing agent. The mercaptan terminated copolymer (MTBN) is considerably less effective as far as tensile strength and heat distortion temperature are concerned. The mercaptan groups are considerably less reactive with epoxides than carboxyls (4), and this difference in the rate of reaction may influence the extent of the epoxy-elastomer copolymerization and therefore the precipitation of the rubber as distinct particles. 

Comparison with Asbestos and Glass. Tables III, IV, V, and VI catalog the properties obtained when the two polystyrenes were reinforced with asbestos and glass. Table VII compares the reinforcing effects of the several fibers studied at 30 wt %. The data show that particular fibers improve particular properties. The tensile modulus and tensile strength are most improved by glass the heat deflection is most improved by asbestos, and the impact strength is most improved by polyester. 

Neoprene is readily crosslinked. Using a nuclear reactor, a high modulus is obtained for doses of 0.04 x 1018 nvt ( 100 Mrad) [439]. Data on other synthetic rubbers have been reviewed by Charlesby [424]. Butyl rubber (polyisobutene) reinforced with carbon black shows a loss in tensile strength and elongation at break and a decrease in modulus. 

Response surfaces showing the effects of composition on mechanical properties are compared with the compatibilized blend and the glass-fiber-reinforced composite in Fig. 5.7 and 5.8. Regression models for the compatibilized blends are shown below the response surface graphs (Fig. 5.7, a-e) versus reinforced (Fig. 5.8, a-e) blends shows a marked difference in the nature of the responses. Most notably, the curvature in the response observed in the compatibilized blends has vanished, and the response is a function of Kraton rubber only for the flexural modulus, notched Izod impact, and tensile strength. Similarly, the heat distortion temperature is now only a linear function of Kraton and HDPE levels. Finally, elongation at break has been reduced to a single value (3.43 0.45%), as more than 90% of the variability in the data was explained by the mean value. Thus,... 

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