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Molecular weight distribution in random branching of polymer chains
Author(s) -
Tobita Hidetaka
Publication year - 1996
Publication title -
macromolecular theory and simulations
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.37
H-Index - 56
eISSN - 1521-3919
pISSN - 1022-1344
DOI - 10.1002/mats.1996.040050110
Subject(s) - branching (polymer chemistry) , polymer , molar mass distribution , degree of polymerization , linear polymer , distribution (mathematics) , polymer chemistry , molecule , polymerization , distribution function , chain (unit) , materials science , polymer science , chemistry , mathematics , thermodynamics , physics , organic chemistry , mathematical analysis , composite material , astronomy
Analytical expressions for the average molecular weights of randomly branched polymer molecules with any primary chain distribution are developed. A full molecular weight distribution (MWD) function is also derived for the case where primary chains conform to the most probable distribution. This MWD function can be separated into the fractional MWDs containing k branch points; therefore, very detailed information on the structure of randomly branched polymers can be obtained. The average molecular weights of the polymer fraction containing k branch points are linear functions of the number of branch points k , and the distribution becomes narrower as k increases. The heterogeneity in the distribution of branch points can make the weight‐average degree of polymerization larger, although it is impossible to form a gel molecule only via branches (T‐shaped junctions) without assistance of crosslinkages (H‐shaped junctions).