Model to predict the mechanical behaviour of oriented rigid PVC

Abstract

Citation: HITT and MIROSHNYCHENKO, 2005 ABSTRACTThe mechanical properties of PVC sheets can be modified substantially by both uniaxial and biaxial stretching of the material above its glass transition temperature. Previous experimental studies have established a clear pattern in the relationship between tensile properties of oriented PVC products and imposed strains. Several mathematical models have been scrutinised to assess whether the established pattern of behaviour can be modelled and predicted. Of these, "the filament theory", proposed by Turner, emerged as the best candidate. The filament theory has been refined and developed further into "the composite model". In its present form it gives a good correlation between predicted and measured yield stress values of oriented rigid PVC sheets and is also capable of predicting the "established pattern" of property dependence upon imposed strain.

Thermal behaviors of heat shrinkable poly(vinyl chloride) film

“…The T g of PVC was lowered by adding a plasticizer. When the material was drawn at temperatures above the T g , the polymer chains were progressively straightened and became loosely aligned in the direction of the applied draw 20. The mechanical properties of PVC can be improved substantially by stretching at temperatures above the T g value.…”

“…The molecular structure of PVC is similar to that of a crosslinked rubber, and the shrinkage is primarily associated with the oriented amorphous parts. The PVC films shrunk in a rubber‐like elasticity, and the shrinkage percent increased with increasing the molecular orientation 20, 22…”

“…The effect of increasing the draw temperature was to improve the dimensional stability of the oriented PVC. Increasing the draw temperature decreases the molecular orientation because of the resultant greater relaxation of the chains at a higher draw temperature 20. It is also suggested that an increase in draw temperature increases the amount and perfection of the crystallites in the structure, which locks the amorphous chain alignment in place, and as a result the whole structure becomes more dimensionally stable 22…”