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Dynamic light‐scattering characterization of the molecular weight distribution of unfractionated polyimide
Author(s) -
Siddiq Mohammad,
Wu Chi
Publication year - 2001
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1598
Subject(s) - polyimide , molar mass distribution , materials science , intensity (physics) , light scattering , calibration , analytical chemistry (journal) , characterization (materials science) , laplace transform , scattering , polymer chemistry , chemistry , polymer , optics , physics , chromatography , composite material , mathematics , nanotechnology , mathematical analysis , layer (electronics) , quantum mechanics
Abstract Using a developed laser light‐scattering (LLS) procedure, we accomplished the characterization of an unfractionated polyimide (UPI) in CHCl 3 at 25°C. The Laplace inversion of precisely measured intensity–intensity time correlation function from dynamic LLS leads us first to an estimate of the characteristic line‐width distribution G (Γ), and then to the translational diffusion coefficient distribution G ( D ). By using a previously established calibration of D (cm 2 /s) = 3.53 × 10 −4 M −0.579 , we were able to convert G ( D ) into a molecular weight distribution. The weight‐average molecular weight M w , calculated from the molecular weight distribution, agrees well with that directly measured in static LLS. Our results indicate that both the calibration and LLS procedure used in this study are ready to be applied as a routine method for the characterization of the molecular weight distribution of polyimide. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1670–1674, 2001