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Acceleration of the polymerization of rodlike molecules by flow

DSpace at IIT Bombay

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Field Value
 
Title Acceleration of the polymerization of rodlike molecules by flow
 
Creator AGGE, A
JAIN, S
KHAKHAR, DV
 
Subject DIFFUSION-LIMITED POLYMERIZATION
ROD-LIKE MOLECULES
SHEAR-FLOW
KINETICS
ENHANCEMENT
 
Description Polymerization of rigid rodlike molecules with reactive end groups (e.g., poly(p-phenylene terephthalamide)) requires near parallel orientation of the molecules. The reaction becomes diffusion-limited as the rotational diffusivity of the reacting molecules decreases to low values in the later stages of the reaction, and this ultimately limits the molecular weight of the polymers formed. Here a theoretical study of the step-growth reaction between rodlike molecules in a solution under extensional flow is carried out. A model for the process is developed using the Smoluchowski approach which yields the effective reaction rate constant for the process in terms of the system parameters. The rate of reaction increases with extensional rate because of flow-induced orientation of molecules, and for sufficiently high extensional rates, the rate constant becomes higher than the intrinsic value. This is an instance where flow has a catalyst-like effect on the reaction. The results indicate that flow can be a useful tool for accelerating reactions and thus improving yield and selectivity for orientation-dependent reactions between large anisotropic molecules.
 
Publisher AMER CHEMICAL SOC
 
Date 2015-01-01T11:33:38Z
2015-01-01T11:33:38Z
2000
 
Type Article
 
Identifier JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 122(44)10910-10913
0002-7863
http://dx.doi.org/10.1021/ja001541r
http://dspace.library.iitb.ac.in/jspui/handle/100/17346
 
Language English