Soy-based UV-curable thiol–ene coatings

Abstract

Novel soy-based thiols and enes were synthesized and characterized. Then, soy-based thiol-ene UV-curable coatings were formulated and their coating physiochemical properties were investigated in detail. The use of biorenewable resources, combined with environmentally friendly UV-curable technology, provides a ''green + green'' solution to the stricter regulations in the coatings industry. Novel soy-based thiols and enes were synthesized through the Lewis acid-catalyzed ring opening reaction of epoxidized soybean oil with multifunctional thiols or hydroxyl functional allyl compounds. FTIR and NMR confirmed the formation of the target compounds. The soy-based thiols and enes were formulated with petrochemicalbased enes and thiols, respectively, to make thiol-ene UV-curable coatings. Typical coating film properties, thermal properties, and photopolymerization kinetics of these coatings were studied. Soy-based thiol-ene coatings having lower functionality thiols and enes have poor UV curability and coating properties, which was attributed to the lower crosslink density. Soybased thiols and enes with higher functionality can be UV-cured in combination with petrochemical-based enes or thiols even without the presence of free radical photoinitiators. Better coating film properties were obtained from these higher functionality thiol-ene systems that were toughened by commercial hyperbranched acrylates.

Acrylated betulin as a comonomer for bio-based coatings. Part I: Characterization, photo-polymerization behavior and thermal stability

“…Some of the polymers coming from vegetable oils are very popular in the coating industry because of their capacity to crosslink by the action of oxygen of the air (Rheineck and Austin, 1968). The properties of oil based coatings are often modified by functional groups containing thiols (Chen et al, 2010), styrenes (Güner et al, 2000), or even urethanes (Guo et al, 2002).…”

Fatty Acid Derived Monomers and Related Polymers Via Thiol‐ene (Click) Additions

“…Very recently, thiol-ene chemistry was also applied for the preparation of bio-based telechelics [31] and soy-based thiols and enes were formulated with allyl triazine resulting in tack-free coating films after UV curing. [32] No detailed studies on the preparation of monomers derived from fatty acids and/or their subsequent polymerization is described in the literature. Therefore, we describe here for the first time the use of methyl-10-undecenoate 2 as a castor oil derived renewable platform chemical in the context of thiol-ene click reactions.…”

Biodegradable polymers from monomers based on vegetable oils

“…Other functional groups such as alcohols, double bonds in side chains, carboxylic acid or halogen groups have been introduced into vegetable oil structures though the ring opening reaction with alcohols (e.g. allyl alcohol (f, Al-SBO) [48], ethylene glycol (j, MHSBO) [49]), maleic acid (g, Ma-SBO) [50] and hydrogen halides (e.g. HCl and HBr (h, HX-SBO) [51]), respectively, and utilized for further application.…”