Fully bio‐based thiol‐ene photocured thermosets from isosorbide and tung oil

Abstract

Direct preparation of coatings from neat vegetable oils without any pretreatment or modification is an elegant way of demonstrating the potential of renewable sources and it is also in line with the principles of Green Chemistry.In this work, photocured coatings were prepared from tung oil (TO), hazelnut oil (HN), and isosorbide. First, a dithiol derivative of isosorbide (ISTMP) was synthesized and then mixed with TO, HN, and a cationic photoinitiator. For comparison, formulations were also prepared by using two different commercial thiol compounds. Coating formulations were applied onto glass substrates and cured under UV light where oxidative polymerization and photoinitiated thiol-ene addition reactions took place concomitantly. Double bond conversion percentages, thermal degradation properties, water contact angles, and surface hardness of the coatings were determined. Furthermore, a model reaction between ISTMP and oleic acid was performed to prove that ISTMP reacts with the fatty acid. ISTMP containing formulation displayed a fast initial double bond conversion and its water contact angle value was found as 88 ± 3 . Rigid and thermally stable isosorbide ring improved both the thermal properties and the surface hardness of the coatings.

Thermally Stable, Solvent Resistant, and Multifunctional Thermosetting Polymer Networks with High Mechanical Properties Prepared from Renewable Plant Phenols via Thiol–Ene Photo Click Chemistry

“…The eugenol has methoxy group and hydroxyl group, while cardanol only possesses a hydroxyl group. In addition, the rigid structure of EU makes the resulting polymers shows better thermal stability than those derived from CA . And the higher cross-linking densities by the higher functionality of thiol linker could also result a high char content; thus, the polymers derived from 4SH show higher char content than those derived from 3SH.…”

Acetylene Dicarboxylic Acid Diallyl Ester: A Versatile Monomer for Thiol–Ene Photocured Networks

“…Owing to the flexible nature of the thioether bonds, thiol-ene systems generally display low modulus values. [12,38] It can be seen from Table 4 that the fully aliphatic base formulation GS has a moderate tensile modulus when compared to a much more common thiol-ene system such as (TTT)/trimethylolpropane tris(3-mercaptopropionate) (3SH), which has a tensile modulus of 44 MPa. [23] The addition of PTA first caused a slight decrement in the tensile modulus but as its ratio in the thermosets was increased, the tensile modulus also increased gradually.…”

“…[3][4][5][6][7] Almost all types of -ene molecules such as allyls, vinylic compounds, acrylates, methacrylates, and maleimides, undergo TEP reactions with thiols via radical induced step-growth mechanism. [8][9][10] TEP can be used to prepare antibacterial coatings, [11] biobased photocured coatings, [12][13][14] adsorbent materials, [15] 3D printed objects, [16] biomolecule immobilization, [17][18][19][20][21] preparation of DOI: 10.1002/mame.202100427 microfluidic devices, [22] hydrophobic coatings, [23][24] and so on. In the case of photocurable coatings, TEP emerges as a very revolutionary method as it produces nontacky surfaces within seconds due its resistance to oxygen inhibition.…”

Metal-Free Click Modification of Triple Bond-Containing Polyester with Azide-Functionalized Vegetable Oil: Plasticization and Tunable Solvent Adsorption

“… 14 The epoxidized vegetable oils are cured thermally with amines, 15 or directly via photoinitiated cationic photopolymerization to synthesize biobased thermoset materials 16 or they are reacted with acrylic acid and used in photocurable coating formulations. 17 Modern techniques such as thiol–ene addition reactions, 18 , 19 azide–alkyne click protocols, 20 and acyclic diene metathesis 21 have also been applied to functionalize/polymerize vegetable oils or their constituents.…”