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Effects of poly(vinyl acetate) and poly(methyl methacrylate) low‐profile additives on the curing of unsaturated polyester resins. I. Curing kinetics by DSC and FTIR
Author(s) -
Huang YanJyi,
Su ChinCheng
Publication year - 1995
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.1995.070550214
Subject(s) - styrene , materials science , differential scanning calorimetry , vinyl acetate , curing (chemistry) , polymer chemistry , polyester , fourier transform infrared spectroscopy , methyl methacrylate , kinetics , copolymer , chemical engineering , composite material , polymer , physics , quantum mechanics , engineering , thermodynamics
The effects of two low‐profile additives (LPA), poly(vinyl acetate) (PVAc) and poly(methyl methacrylate) (PMMA) on the curing kinetics during the cure of unsaturated polyester (UP) resins at 110°C were investigated by using a differential scanning calorimeter (DSC) and a Fourier transform infrared spectrometer (FTIR). The effects of temperature, molar ratio of styrene to polyester CC bonds, and LPA content on phase characteristics of the static ternary systems of styrene–UP–PVAc and styrene–UP–PMMA prior to reaction were presented. Depending on the molar ratio of styrene to polyester CC bonds, a small shoulder or a kinetic‐controlled plateau in the initial portion of the DSC rate profile was observed for the LPA‐containing sample. This was due to the facilitation of intramicrogel crosslinking reactions since LPA could enhance phase separation and thus favor the formation of clearly identified microgel particles. FTIR results showed that adding LPA could enhance the relative conversion of polyester CC bonds to styrene throughout the reaction. Finally, by use of a microgel‐based kinetic model and static phase characteristics of styrene–UP–LPA systems at 25°C, the effects of LPA on reaction kinetics regarding intramicrogel and intermicrogel crosslinking reactions, relative conversion of styrene to polyester CC bonds, and the final conversio have been explained. © 1995 John Wiley & Sons, Inc.