Elongation ultimate

Rubber Specific gravity Durometer hardness (or Shore) Ultimate elongation % (23°C) Tensile strength, lb in 2 (23°C) Service temperature, °C ... 

The presence of spherulites or smaller crystallites is comparable to cross-linking and affects not only the moduli and compliances, but also the ultimate properties such as yield strength and ultimate elongation. 

In air, PTFE has a damage threshold of 200—700 Gy (2 x 10 — 7 x 10 rad) and retains 50% of initial tensile strength after a dose of 10" Gy (1 Mrad), 40% of initial tensile strength after a dose of 10 Gy (10 lad), and ultimate elongation of 100% or more for doses up to 2—5 kGy (2 X 10 — 5 X 10 rad). During irradiation, resistivity decreases, whereas the dielectric constant and the dissipation factor increase. After irradiation, these properties tend to return to their preexposure values. Dielectric properties at high frequency are less sensitive to radiation than are properties at low frequency. Radiation has veryHtde effect on dielectric strength (86). 

Plastic film Melting point, °C Moisture absorption, % Tensile strength, MPa " Ultimate elongation, % Coefficient of thermal expansion, 10-%K Dissipation factor at 1 kH2 Dielectric constant at 1 kHz Dielectric strength, MV/m Cost factor... 

Creep tests are ideally suited for the measurement of long-term polymer properties in aggressive environments. Both the time to failure and the ultimate elongation in such creep tests tend to be reduced. Another test to determine plastic behavior in a corrosive atmosphere is a prestressed creep test in which the specimens are prestressed at different loads, which are lower than the creep load, before the final creep test (11). 

Temper Yield strength Ultimate Elongation, % in RockweU Electrical... 

DOP (% by weight) Tensile strength (MPa) Ultimate elongation (%) Permanent deformation (%) Hardness (°ShA) T (K)... 

An important consideration is the effect of filler and its degree of interaction with the polymer matrix. Under strain, a weak bond at the binder-filler interface often leads to dewetting of the binder from the solid particles to formation of voids and deterioration of mechanical properties. The primary objective is, therefore, to enhance the particle-matrix interaction or increase debond fracture energy. A most desirable property is a narrow gap between the maximum (e ) and ultimate elongation ch) on the stress-strain curve. The ratio, e , eh, may be considered as the interface efficiency, a ratio of unity implying perfect efficiency at the interfacial Junction. 

The first point of zero slope on the curve (point C) is identified with material yielding and so its coordinates are called the yield strain and stress (strength) of the material. The yield strain and stress usually decrease as temperature increases or as strain rate decreases. The final point on the curve (point D) corresponds to specimen fracture. This represents the maximum elongation of the material specimen its coordinates are called the ultimate, or failure strain and stress. Ultimate elongation usually decreases as temperature decreases or as strain rate increases. 

Physical properties (ASIM methods in parentheses) Gel time = 2-5 min hardness (D2240) = 49 Shore D (>90 Shore A) tensile strength (D412) = 2393 pounds per square inch (psi) ultimate elongation (D412) = 103% die C tear (D624 — 91) = 341 foot-pounds per inch (Ibf/in.) split tear (D3489 — 90) = 97 lbf/in. I g(DMA) = -50°C. 

The material should have these properties gel time = 2—5 min hardness (D2240 ) = 95 Shore A Bashore resilience (D2632) = 60 % tensile strength (D412) = 5400 psi ultimate elongation (D412) = 500% die C tear (D624) = 610 Ibf/in. 

Similar types of lamellar morphologies were observed for triblock copolymers of diphenylsiloxane and dimethylsiloxane having 40 wt% polydiphenylsiloxane, using electron microscopy, 47-148>. The lamellae thickness was approximately equal to the chain length of the rigid polydiphenylsiloxane blocks. These copolymers showed elastomeric properties comparable to those of conventional silica-reinforced, chemically crosslinked silicone rubbers. Tensile tests yielded an initial modulus of 0.5-1 MPa, tensile strength of 6-7 MPa and ultimate elongation between 400 and 800 %. 

Stress-strain tests of these perfectly alternating PDMS-PSF copolymers show that the mechanical behavior is dictated by the volume fraction of PDMS present in the system. At high siloxane content (> 70 wt %), copolymers show elastomeric behavior Hue to the presence of continuous PDMS matrix. An increase in the PSF content resulted in an increase in the initial modulus and the ultimate tensile strength of these materials, while a decrease in the ultimate elongation was also observed, as expected. 

---