Chain architecture melt rheology

Dorgan J.R., Williams J.S., Lewis D.N., Melt rheology of poly(lactic cid) Entanglement and chain architecture effects, J. RheoL, 43(5), 1999,1141-1155. 

Fundamental polymer chain characteristics such as the characteristic ratio and the molecular weight can be quantitatively related to the melt rheological response. Because of this fact, it is important to be able to characterize these quantities. Several techniques are available, with multiple angle laser hght scattering (MALLS) playing an important role. However, viscometry is the simplest technique for characterizing polymer chains of known molecular architecture. 

H. J. Lehermeier, J. R. Dorgan, Melt rheology of poly(lactic acid) consequences of blending chain architectures. Polym. Eng. Sci. 2001, 41, 2172-2184. 

Dorgan, J. R., Williams, J. S. Lewis, D. N. (1999). Melt rheology of pely(lactic add) Entanglement and chain architecture effects. Journal of Rheology 43(5) 1141-1155. 

The final chapter develops the most modern insights in the relation between the rheological properties and the large scale architecture of polymers. Indeed, the largest effects of branching are encountered in their melt relaxation properties. In the absence of reptation, which dominates relaxation processes in Hnear polymers, a rich variety of other relaxation processes becomes apparent. The control ot the melt properties of polymers by means of their long-chain branch architecture will continue to lead to new industrial applications. 

---