Kosin Wutticharoenwong, M. Soucek
Jan 14, 2008
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0
Influential Citations
26
Citations
Journal
Macromolecular Materials and Engineering
Abstract
Photopolymerization kinetics of difunctional thiols with alkenes were studied. Two of the thiols, trans-1,4-bis(mercaptomethyl)cyclohexane (CHDMT) and 1,4-bis(mercaptomethyl)benzene (BDMT) were synthesized. The CHDMT was synthesized via a two step process using potassium thioacetate and hydrochloric acid as reagents. The BDMT was synthesized by a one step process using 1,4-benzenedimethanebromine with thiourea and potassium hydroxide as reagents. Three types of alkenes (divinyl ether, diallyl ether, and dimethacrylate) were reacted with CHDMT, BDMT or 1,8-octanedithiol (ODT). The photopolymerization was investigated with and without a photoinitiator. The kinetics of the thiol-ene photopolymerization was investigated by time-resolved infrared spectroscopy. It was proposed that the steric hindrance of the cyclohexane (CHDMT) resulted in a lower rate of photopolymerization compared to BDMT and ODT. The vinyl ether (alkene) exhibited the highest activity compared to allyl ether and acrylate which was attributed to a high electron density of the alkene. Incorporation of photoinitiator increased the reaction rate and final conversion of the system, particularly in the ODT system.