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Heat‐ and light‐induced thiol‐ene oligomerization of soybean oil‐based polymercaptan
Author(s) -
Bantchev Grigor B.,
Vermillion Karl E.,
Lansing James C.,
Biresaw Girma
Publication year - 2018
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.46150
Subject(s) - gel permeation chromatography , dispersity , chemistry , polymer , ene reaction , polystyrene , polymer chemistry , degree of unsaturation , sulfide , thiol , viscometer , size exclusion chromatography , depolymerization , chromatography , viscosity , organic chemistry , materials science , composite material , enzyme
Polymercaptanized soybean oil (PMSO), the product of a thiol‐ene reaction between soybean oil and hydrogen sulfide, is a material of interest as a lubricant additive and polymer precursor. We investigated with gel permeation chromatography, nuclear magnetic resonance (one‐dimensional and two‐dimensional), gas chromatography–mass spectrometry, and viscometry the changes that occur with PMSO upon heating or ultraviolet irradiation. The observed changes were due to a further thiol‐ene reaction between the thiol groups and the residual unsaturation. The formation of oligomers was a result of new sulfide bridges. Additionally, tetrahydrothiophene moieties were detected. An almost linear increase of the average molecular weight (MW) and the polydispersity index (PDI) was observed upon heat treatment [number‐average MW ( M n ) = 1180 Da, PDI = 1.32 for PMSO,M n = 1720 Da, PDI = 2.17 for PMSO that was heated for 1000 h at 130 °C]. PDI correlated best with the z ‐average MW. TheM nwas the best predictor of the viscosity. For samples with closeM n , the higher PDI corresponded to a higher viscosity index. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46150.