Development in Polymer Flows

Morphological Development in Polymer Flows.—Keller and Mackley have made a number of studies of what may be termed hydrodynamically induced orientation and crystallization, as has Pennings. These and other studies essentially established the general conclusion that crystallization from a flowing polymer melt will result in a composite fibrillar-lamella (shishkebab) structure. 

Klason and J. Kubat, Gothenburg, Sweden, Chalmers Univ., 1976. 

Pennings, in Proceedings of the International Conference on Crj stal Growth Pergamon, Oxford, 1966, pp. 389 If. 

Chemo-rheology.— The presence of the partially uncoiled molecular chains in the flowing melts referred to above ensiu s that the viscoelastic behaviour will be complex. Boger and Nguyen display excellent photographs of a viscoelastic flow pattern upstream of the convergent die. Their experiments are based 

In a study which has links with the order concepts in flow induced crystallization (see above), Hlavacek and co-workers have interpreted elastic melt flow instability as an order-disorder phenomenon. Transition occurs when tlie rate of order generation (negentropy production) imposed by the flow exceeds a 

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