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SHEAR-FLOW INDUCED ORIENTATION DEVELOPMENT DURING HOMOGENEOUS SOLUTION POLYMERIZATION OF RIGID RODLIKE MOLECULES

DSpace at IIT Bombay

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Title SHEAR-FLOW INDUCED ORIENTATION DEVELOPMENT DURING HOMOGENEOUS SOLUTION POLYMERIZATION OF RIGID RODLIKE MOLECULES
 
Creator AGARWAL, US
KHAKHAR, DV
 
Subject rod-like macromolecules
angle light-scattering
rheooptical response
concentrated-solution
collagen protein
liquid-crystals
chains subject
sulfuric-acid
polymers
dynamics
 
Description The dynamic variation of optical birefringence during solution polycondensation of rigid rodlike molecules 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 (Agarwal, U. S.; Khakhar, D. V. Nature 1992, 360, 53). The birefringence at different shear rates (gamma) over the course of the polymerization is found to depend only on gamma/D(r), where D(r) is the rotational diffusivity. The predictions of the theory of Marrucci and Grizzuti (J. Polym. Sci., Polym. Lett. Ed. 1983, 21, 83), however, show large deviations in comparison to the experimental birefringence measurements. The experiments are carried out using terephthaloyl chloride and p-phenylenediamine to produce poly(p-phenyleneterephthalamide) in a mixed solvent at low temperatures. A two-reactor system is used in which the second reactor is designed to give a uniform simple shear flow and to allow for measurement of birefringence during polymerization.
 
Publisher AMER CHEMICAL SOC
 
Date 2011-07-14T20:04:56Z
2011-12-26T12:47:36Z
2011-12-27T05:37:04Z
2011-07-14T20:04:56Z
2011-12-26T12:47:36Z
2011-12-27T05:37:04Z
1993
 
Type Article
 
Identifier MACROMOLECULES, 26(15), 3960-3965
0024-9297
http://dx.doi.org/10.1021/ma00067a035
http://dspace.library.iitb.ac.in/xmlui/handle/10054/4054
http://hdl.handle.net/10054/4054
 
Language en