Schatzki crankshaft effect

Many polymers undergo second order transitions at temperatures below T, [224] the transitions are caused by rotations of side groups about an axis which is perpendicular to the chain, by the motion of sequences of 3 — 5 methylenic groups from the backbone or by motion of chain portions in polymers containing heteroatoms in the main chain [162, 226]. The second kind of motion, noted by Schatzki [226] in ethene copolymers and in many homopolymers, is referred to as the crankshaft effect and it occurs immediately below T,. Because it is almost insensitive to the... 

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