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Crosslinking of unsaturated polyester resins studied by low‐resolution 1 H‐NMR spectroscopy
Author(s) -
Hietalahti Karin,
Root Andrew,
Skrifvars Mikael,
Sundholm Franciska
Publication year - 1997
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/(sici)1097-4628(19970705)65:1<77::aid-app10>3.0.co;2-w
Subject(s) - polyester , curing (chemistry) , styrene , materials science , polymer chemistry , polymer , proton nmr , copolymer , chemistry , composite material , organic chemistry
The curing behavior of five unsaturated polyester resins with different molar ratios of styrene to the double bonds in the polyester chain (MR) was investigated. The gel time was measured according to a standard method by the Society of the Plastic Industry (SPI) and by low‐resolution pulse nuclear magnetic resonance (LRP‐NMR). The gel and curing times decreased and the maximum temperature of the reaction increased when the MR was decreased. The proton mobilities and populations were measured by LRP‐NMR. Three components could be seen in the crosslinking reaction: styrene (very mobile, T 2 ≅ 3 s), free polyester polymers (less mobile, T 2 ≅ 150 ms), and cured resin (immobile, T 2 ≅ 0.04 ms). The third component, cured resin, could be detected at the gel point. At this point, the proton mobilities of styrene and free polyester polymers were rapidly decreasing and the proton populations of the cured resin started to increase. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 77–83, 1997