Polyethylene semicrystalline nature

Given the estimated properties of each phase and assuming a model of connectivity via the interface, it is possible to explain the mechanical behavior of polyethylene samples. To carry out this type of analysis it is desirable to have an accurate knowledge of the relative proportions of each of the three phases. In practice the single term degree of crystallinity is frequently used to characterize the semicrystalline nature of polyethylene samples. Quantification of the three phases of polyethylene can be made experimentally by several methods [1-3], the degree of crystallinity by many more [4-6], The experimental determination of the relative amounts of each of the phases is addressed in Chapter 6. Some of the most commonly used and most important descriptors of a polyethylene sample, such as density and stifiness, are closely related to its ciystallin-... 

Chlorinated polyethylene (CPE) n. Any polyethylene modified by simple chemical substitution of chlorine on the hnear backbone chain, CPEs range from rubbery amorphous elastomers at 35-40% Cl to hard, semicrystalline materials at 68-75% Cl. They are sometimes included with chlorinated natural and butyl rubbers under the term chlorinated rubbers. Certain CPEs are used as modifiers in PVC compounds to obtain better flexibihty and toughness, particularly low-temperature toughness, greater latitude in compounding, and ease of processing. 

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