Chain dimensions Polyolefins

This number appears to be constant for flexible polymers, with the average value = 20.6( 8%). Table 25.1 shows data for polyolefin melts listing density p, plateau modulus Ge, melt chain dimensions from SANS o/M, entanglement molar mass Me calculated from Eq. (25.6), Kuhn length b, packing length p, tube diameter a, and the overlap parameter for entanglement P, all at temperature T. 

Long chain branching occurs in many polyolefins, e.g., LDPE. The presence of long chain branching affects the solution properties of the polymer, as well as its properties in the melt and in the solid state. Since long chain branching causes decreases in the dimensions of... 

We have briefly reviewed methods for estimation of polymer unperturbed dimensions and the variation of unperturbed dimensions with temperature. The impact of various structural features on chain conformations has been ducid-ated. Special attention has been devoted to poljnmethacrylates, polydienes, and polyolefins. Stiff chain polymers have also been discussed briefly. 

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