Polyethylene terephthalate physical structure

In this review recent theoretical developments which enable quantitative measures of molecular orientation in polymers to be obtained from infra-red and Raman spectroscopy and nuclear magnetic resonance have been discussed in some detail. Although this is clearly a subject of some complexity, it has been possible to show that the systematic application of these techniques to polyethylene terephthalate and polytetramethylene terephthalate can provide unique information of considerable value. This information can be used on the one hand to gain an understanding of the mechanisms of deformation, and on the other to provide a structural understanding of physical properties, especially mechanical properties. 

Categorize the following polymers with regard to their low-temperature physical structure polyethylene isotactic polypropylene poly (ethylene terephthalate) isotactic polystyrene atactic polystyrene atactic poly(vinyl alcohol) atactic poly(vinyl acetate) poly(ethylene-sfflf-propylene) with 50/50 molar composition, and the same polymer but with molar composition 98/2. 

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