Shear flow induced orientation development during homogeneous solution polymerization of rigid rodlike molecules

Abstract

The dynamic variation of optical birefringence during solution polycondensation of rigid rodlike molecules (p-phenylenediamine and terephtaloyl chloride) in a simple shear flow is obtained. At relatively high shear rates (413 s -1 ) and late stages of the polymerization the orientation of the molecules is found to be significant. Molecular orientation is important in such reactions since it increases the polymerization rate and alters the molecular weight distribution. The birefringence at different shear rates γ over the course of the polymerization is found to depend only on γ/D r , where D r is the rotational diffusivity