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Effect of moisture on cationic polymerization of silicone epoxy monomers
Author(s) -
Ranaweera R. A. A. Upul,
Schuman Thomas P.,
Wang Rongpeng,
Miller Bradley D.,
Kilway Kathleen V.
Publication year - 2015
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.41831
Subject(s) - cationic polymerization , epoxy , polymerization , materials science , silicone , monomer , ultimate tensile strength , polymer , polymer chemistry , moisture , composite material , ionic strength , fourier transform infrared spectroscopy , chemical engineering , chemistry , aqueous solution , organic chemistry , engineering
ABSTRACT Moisture in polymerization of a cationically cured silicone epoxy monomer blend is an important parameter that affects the resulting polymer properties. We report the kinetics of the cationic polymerization of epoxy monomers as a function of water concentration, directly quantified using Karl Fischer (KF) titration that was characterized using Fourier transform infrared (FTIR) spectroscopy and also the mechanical strength of resulting polymers via diametral tensile strength measurements. Methodology and results for a silicone epoxy monomer material were compared with the same methodology applied to a “control” monomer, 3,4‐epoxycyclohexylmethyl 3,4‐epoxycyclohexyane carboxylate, for which moisture effects have been previously studied. Initially, an increase in moisture during cationic polymerization of epoxy caused increased rate (ROC) and degree of conversion (DOC) that for the silicone epoxy was followed by decreased DOCs for water contents approaching saturation, i.e., [H 2 O]∼0.19 wt %. Further, the rate of conversion was also affected by the presence of moisture with a trend analogous to the DOC. Diametral tensile strength measurements found that small amounts of water present during polymerization caused small changes in tensile strength but found polymer strengths to be significantly decreased if initial water concentrations approached saturation or were in excess of saturation. Lower strengths corresponded with reduced rates of conversion and DOCs. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 41831.