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Distributed midpoint chain scission in ultrasonic degradation of polymers
Author(s) -
Sivalingam G.,
Agarwal Nitin,
Madras Giridhar
Publication year - 2004
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.10185
Subject(s) - molar mass distribution , polymer , gel permeation chromatography , dispersity , chemistry , polymer chemistry , benzene , breakage , analytical chemistry (journal) , materials science , thermodynamics , organic chemistry , composite material , physics
The ultrasonic degradation of poly(bisphenol A carbonate), poly(ε‐caprolactone), and poly(vinyl acetate) was investigated with various solvents such as benzene, monochlorobenzene, and dichlorobenzene. The time evolution of molecular weight was determined using gel permeation chromatography. A limiting molecular weight was observed for all the systems and was a function of solvent properties. The degradation rates increased with increase in viscosity and decrease in vapor pressure. The polydispersity reached a maximum before reaching a constant value at longer times. The experimental data indicate that the breakage of the polymer is around midpoint, with a distribution rather than an ideal midpoint scission. A continuous distribution model with a stoichiometric kernel based on Lorentzian probability distribution function was developed to satisfactorily model the experimental data. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2258–2265, 2004