Tensile elongation unit

Polymer Tensile strength (units) Modulus (unit) (mode) Elongation (%) CTE (ppm) Reference... 

Sample Number Radiation Dose, kGy Tensile Elongation at Break, % Gardner Impact Strength, inXlb Elexural Deflection at Peak Load, mm Color, Hunter b Units ... 

An important application of Eq. (3.39) is the evaluation of M, . Flory et al.t measured the tensile force required for 100% elongation of synthetic rubber with variable crosslinking at 25°C. The molecular weight of the un-cross-linked polymer was 225,000, its density was 0.92 g cm , and the average molecular weight of a repeat unit was 68. Use Eq. (3.39) to estimate M. for each of the following samples and compare the calculated value with that obtained from the known fraction of repeat units cross-linked ... 

Values of stress and strain obtained from Figure 1 and from similar plots of data obtained on the other elastomers yield the plots of Xo vs. (X — 1) in Figure 2, where Xo is the true stress, i.e., the force per unit cross-sectional area of the deformed specimen. The data at strains up to 1.0 (100% elongation) give straight lines whose slopes equal the equilibrium tensile moduli, E values of 1 /3 are given in Table I. 

Tensile stress-strain tests give another elastic constant, called Poisson s ratio, v. Poisson s ratio is defined for very small elongations as the decrease in width of the specimen per unit initial width divided by the increase in. length per unit initial length on the application of a tensile load ... 

Except at very low strains, up to about 15%, the ratio of stress to strain in vulcanised rubber is not a constant. Modulus is the tensile stress (measured in MPa, lb/in2 or kg/cm2) required to stretch the rubber to a given strain (or elongation) the elongation must always be stated, otherwise the expression is meaningless. A more precise expression is stress per square unit (in2 or cm2) at the given strain . 

The tensile strength and tensile modulus decrease and the elongation increases by the introduction of fluorine atoms into isopropylidene units of Bisphenol A poly(carbonate) (3),6 i.e., poly(carbonate) becomes more flexible by the introduction ofhexafluoroisopropylidene units. The increased flexibility is attributed to the weaker intermolecular interaction induced by fluorine atoms. 

Physical characterization of polymers is a common activity that research and development technologists at the Dow Chemical Company perform. A material property evaluation that is critical for most polymer systems is a tensile test. Many instruments such as an Instron test frame can perform a tensile test and, by using specialized software, can acquire and process data. Use of an extensometer eliminates calibration errors and allows the console to display strain and deformation in engineering units. Some common results from a tensile test are modulus, percent elongation, stress at break, and strain at yield. These data are then used to better understand the capabilities of the polymer system and in what end-use applications it may be used. 

On the other hand, tensile strength was reduced with an increase in the mole fraction of cocrosslinkers, whereas the elongation and fracture energy showed reverse dependences. In addition, good correlations between the mechanical properties and v were observed, regardless of the length of glycol units of cocrosslinkers. 

In another set of experiments, tensile specimens initially 0.015 in. thick were elongated to various extents, released, and subsequently X-rayed. The resulting data can be analyzed by pole figure techniques to give the complete orientation distribution of unit cells in the specimen. For the case of axial specimen... 

---