Cationic UV-Curing of Epoxidized Biobased Resins

Abstract

Epoxy resins are among the most important building blocks for fabrication of thermosets for many different applications thanks to their superior thermo-mechanical properties and chemical resistance. The recent concerns on the environmental problems and the progressive depletion of petroleum feedstocks have drawn the research interest in finding biobased alternatives. Many curing techniques can be used to obtain the final crosslinked thermoset networks. The UV-curing technology can be considered the most environmentally friendly because of the absence of volatile organic compound (VOC) emissions and mild curing conditions. This review provides an overview of the state of the art of bio-based cationic UV-curable epoxy resins. Particular focus has been given to the sources of the bio-based epoxy monomers and the applications of the obtained products.

Lanthanide‐Doped Nanoparticles for Near‐Infrared Light Activation of Photopolymerization: Fundamentals, Optimization and Applications

“…When the growing chain radical encounters with another radical, the propagation stops and chain polymerization process is also terminated [11a] . The cationic polymerization has also attracted increasing attentions due to some excellent properties, such as, dark reaction without light source, [36] no oxygen inhibition, [37] weak toxicity, [38] small volume shrinkage [39] and high thermal resistance [33] . The primary used photoinitiators for cationic polymerization are onium‐based salts, such as diary‐ liodonium, [40] and triarylsulfonium [41] .…”

Isoprene Soya Diels–Alder Adduct and Epoxidation for Photopolymerization

“…Consequently, there is a strong demand for the industrial utilization of renewable feedstocks. [ 1,2 ] Seed and fish oils which are triglycerides of fatty acids were the dominant coating vehicle in the 19th century. The seed oils were carried onto the 20th century as one of the feedstocks for alkyds.…”

Recent advances on chalcone-based photoinitiators of polymerization

“…[14,15] As a major advantage, photopolymerization can be carried out in solvent-free conditions so that the release of volatile organic compounds can be greatly reduced. [16][17][18][19] Parallel to this, the polymerization process can also be extremely fast (within a few seconds) so that this polymerization technique has become unavoidable for the practice of modern dentistry with the omnipresence of dental light curing materials (See Figure 1). [20][21][22] If UV photopolymerization was popular during decades in industry due to the possibility to produce colorless coatings by using colorless photoinitiators, [4] conversely, visible light photopolymerization is facing a major issue with the use of colored photoinitiators often imposing the color to the final coatings due to the lack of photobleaching during the polymerization process.…”

“…Figure 22. Polymerization profiles obtained during the FRP of PEG-diacrylate upon irradiation at 405 nm with a LED (100 mW/cm²) a) chalcones C58-C66 (curves 1-9) b) C67-C73 (curves 11-17). Reprinted from[238] Copyright (2020), with permission from Elsevier.…”