Elastomers tensile strength data

Tensile Strength Data from Selected EB-Irradiated Elastomers... 

Efficiencies of radiation-induced reactions of selected elastomers are shown in Table 5.5. Tensile strength data from another group are shown in Table 5.6. 

Figure 5.11. True tensile strength data for several types of segmented diisocyanate-linked polyurethane elastomers as function of urethane content. (Havlik and Smith, 1964.)...

Data are presented which illustrate that the tensile strength and elongation-at-break depend significantly on the extension rate even when the stress remains in equilibrium with the strain prior to fracture. A crude estimate was made of the threshold (lowest possible) values of the true stress-at-break and the elongation-at-break for the TIPA elastomer. The estimated quantities are about 26% less than those found at an extension rate of about 0.01 min-1 at 30°C. 

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. 

The physical data (dynamic modulus, tensile strength, hardness, elongation at break) were investigated by many groups 202,205 210) (cf., Table 4.5 as an example). These results show that the elastomer physical properties become better by increasing the molar ratio of low-molecular-weight diol to hydroxyl-terminated polybutadiene. 

These data show that urethane elastomers based on MDI type prepolymer cured with 1,4-butanediol exhibit equivalent or even better physical properties, such as tensile strength, compression set, resilience, tear strength and elongation when compared to elastomers extended with methylene bis (2-chloroaniline), trimethylene glycol di-p-aminobenzoate or hydroquinone bis(2-hydroxyethyl) ether in MDI or TDI system (at equal hardness). Other advantages for 1,4-butanediol curative are low toxicity, liquid state at room temperature, ease of handling and lower cost than other well-known curatives. 

Figure 10.65. Dependence of tensile strength of the filled crosslinked elastomer of natural rubber on the swelling ratio in different plasticizers 1 DMP 2 DBF 3 DOP 4 DBS 5 vaseline oil. [Data from Dogad-kin B A, Fedukin D L, Gul V E, Colloid J., XIX, 217, 1957.1...

Fig. 66 Comparation on the effect induced by EB-irradiation in some elastomers (electron raiergy 10 MeV). The data were taken from [GOBI], tensile strength (b) elongation at break (c) modulus at 50 % elongation (white) natural rubber (grey) ethylene-propylene diene terpolymer (black) nitrile rubber.

Further data from the Watkins paper have been summarized in Fig. 5. This rates a number of elastomers according to cumulative change in physical properties as an index of total change (example tensile strength - 20%, elongation - 30%, hardness + 10 total index 60 points change). 

Table 12.2 summarizes the mechanical properties of polybutadiene rubber-clay nanocomposites. The hardness, tensile strength, elongation at break, and permanent set all improved with increasing the clay content (5—40 phr)." " The mechanical properties of polybutadiene rubber-clay nanocomposite with 20 pin-clay content have been compared to those of the polybutadiene composites filled with 20 phr carbon black (SFR and N330), as presented in Table 12.3. This data shows that the organically-modified layered silicate was as effective a reinforcing filler, as carbon black. Some of the mechanical properties of polybutadiene nanocomposite such as hardness, tear strength, and tensile strength even exceeded those of the carbon black filled compounds." " These excellent mechanical properties of the nanocomposites resulted from the uniformly dispersed layered silicate in the elastomer matrix, and the strong interaction between the nanoclay layers and rubber chains. Thus layered silicates could be used in the polybutadiene industry as a promising reinforcing filler, if the layers...

Following are selected data for the most often used polymers. They have been divided (partly arbitrarily, because of the overlap in definitions) into four tables, numbered from 24.3 to 24.6 respectively, for general purpose polymers, engineering polymers, thermosets, and elastomers. The third colunm in each of these tables shows the values of density, the fourth of the tensile modulus, the fifth the stress at break, the sixth the elongation at break IS denotes the Izod impact strength for notched specimens. The letters A and C in the last column in Tables 24.3 and 24.4 pertain respectively to amorphous and crystalline thermoplastic polymers. 

---