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Characterization of linear copolymers by methods sensitive to the refractive index increment
Author(s) -
Rodríguez Rogelio
Publication year - 1988
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760280804
Subject(s) - dispersity , refractive index , copolymer , materials science , chemical composition , monomer , scattering , molecule , light scattering , polymer , quadratic growth , molar mass distribution , polymer chemistry , optics , thermodynamics , mathematics , chemistry , organic chemistry , physics , mathematical analysis , composite material , optoelectronics
For linear copolymer molecules, the refractive index increment depends on the chemical composition of the molecules. However, the polydispersity in chemical composition of the sample introduces a great complexity in the data analysis in order to obtain a true molecular weight distribution. Even when the mean chemical composition does not depend on the molecular weight, a correction has to be applied when the output of an instrument depends quadratically on the refractive index Increment of the sample, such as in a light‐scattering measurement. For that purpose, the light‐scattering expressions are written in terms of polydispersity in chemical composition, which in turn is modeled using linear copolymerization equations. The microstructure effects, which are related to the order in which two different kinds of monomers appear along the chain, are not as yet taken into account in this approach.