Solution entanglement number

Prom the series of experiments reported above it is evident that chain folding at the interphase plays an important role in packing of the chains within the crystalline lattice. In this section we aim to investigate the influence of the interphase on the melting behaviour of crystals and its implications in the polymer melt. Material investigated for the purpose is a solution crystallized UHMW-PE. Salient features on the material have been summarized in the section 4 of this chapter and details have been provided in [31]. Since the solution crystallized UHMW-PE is made from dilute solutions, the number of entanglements between the crystalline and amorphous regions is reduced to an extent that the material can be drawn in the solid state (Fig. 15.5) by more than 100 times. 

For polymer melts or solutions, Graessley [40-42] has shown that for a random coil molecule with a Gaussian segment distribution and a uniform number of segments per unit volume, a shear rate dependent viscosity arises. This effect is attributed to shear-induced entanglement scission. 

For concentrated polystyrene solutions (c>c ) in n-butylbenzene, Graessley and co-workers [36] observed that the shift factor hconc depends on the number of entanglements per macromolecule E. 

The globular structure of the dendritic polymers and the missing entanglement results in low viscosity in solution [47]. In addition to improved solubility, the presence of large number of functional terminal groups unlike that of linear polymers,... 

Thus in the mesoscopic approximation or, in other words, in the mean-field approximation, the dynamic shear modulus of the melt or the concentrated solution of the polymer (strongly entangled systems) is represented by a function of a small number of parameters... 

Thurston GB, Peterlin A (1967) Influence of finite number of chain segments, hydrodynamic interaction, and internal viscosity on intrinsic birefringence and viscosity of polymer solutions in an oscillating laminar flow field. J Chem Phys 46(12) 4881 4884 Treloar LRG (1958) The physics of rubber elasticity. Oxford University Press, London Tsenoglou C (2001) Non-Newtonian rheology of entangled polymer solutions and melts. Macromolecules 34 2148-2155... 

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