Draw ratio at break

Counit type M (x10- ) Counit (moi%) Crystaiiinity (%) Oc (%) a (%) b (%) iVloduius (iVIPa) Yieid stress (iVIPa) Ultimate tensile stress Draw ratio at break... 

Figure 1.3 shows the tensile strength and the maximum draw ratio at break as a function of cisitrans content. The tensile strength of 3.8 kg mm for a 98% cis film decreased only gradually with decreasing cis content to 2,4 kg mm for a 96% trans film. On the other hand, elongation to break decreased rapidly... 

The mechanical propterties of polyethylene may be divided into two broad categories (1) low strain properties sueh as yield stress and initial modulus and (2) high strain properties, typified by ultimate tensile strength and draw ratio at break. To a first approximation, the low strain properties are controlled by a sample s morphological features, and the high strain properties by its molecular characteristics. 

Figure 12 Plot of draw ratio at break as a function of molecular weight for compression-molded linear polyethylene resins. (Data from Refs. 103 and 105.)...

Orientation of polyethylene introduces anisotropy with respect to virtually every physical property. At extreme levels of orientation, the degree of anisotropy developed surpasses that attainable by any other polyolefin and is unmatched by other organic polymers with the exception of carbon fibers. Most deliberate attempts to orient polyethylene to high degrees are made with the intent of improving mechanical properties, especially tensile modulus. It is therefore no surprise that the majority of literature references to highly drawn polyethylene detail the effects of orientation on such mechanical properties as elastic modulus, tensile strength, and draw ratio at break. 

---