The Photoinitiated Cationic Polymerization of 3,4-Epoxy-1-butene

Abstract

The photopolymerization of 3,4-epoxy-1-butene (1) was investigated using Fourier transform real-time infrared spectroscopy. The effects of photoinitiator structure and concentration and light intensity on the photopolymerization were investigated. Monomer 1 was found to be more reactive than its saturated analog, 1,2-epoxybutene, and its halogenated derivatives, 3,4-dibromo-1,2-epoxybutane and 3,4-dichloro-1,2-epoxybutane.

Photoinduced Synthesis of Oligoesters

“…Photoinitiated polymerization is usually referred to as a chain process that is initiated by light and both the initiating species and the growing chain ends are radicals , and cations, , and in some cases, anions. − However, the corresponding polycondensation process in which a macromolecule is obtained by a step-growth addition of low-molecular-weight materials, referred to as photopolymerization, has been scarcely dealt with. In most cases, − the photopolymerization process is based on the dimerization of the nonconjugated olefins through singlet and triplet excited states and the obtained macromolecules do not represent the classical polycondensate structure such as those of polyesters, polyamides, and polyurethanes.…”

N-Vinylcarbazole: As an Additive for Thermal Polymerization at Room Temperature with in situ Formation of Ag(0) Nanoparticules

“…Thermally and photochemically induced free radical polymerizations (FRP) have been the subject of numerous studies [13][14][15][16][17][18]. In thermal FRPs, redox initiated processes are very attractive due e.g., to the absence of solvents and the use of quite low reaction temperatures.…”

“…In thermal FRPs, redox initiated processes are very attractive due e.g., to the absence of solvents and the use of quite low reaction temperatures. However, such FRPs suffer from a strong drawback concerned with the well-known oxygen inhibition [13][14][15][16][17][18][19][20]. Indeed, both the initiating (Scheme 1(r1)) and propagating (Scheme 1(r2)) radicals are scavenged by O2 and converted into stable peroxyl radicals, which cannot participate in any further polymerization initiation reactions and lead to a decrease of both polymerization rates and final conversions (Scheme 1) [21][22][23][24].…”

Trialkyl Phosphites and Diaryliodonium Salts as Co-initiators in a System for Radical-Promoted Visible-Light-Induced Cationic Polymerization

“…Diaryliodonium salts (Ar 2 I + Y – ) with non-nucleophilic anions (e.g., PF 6 – , BF 4 – ) have long been known to function as photoinitiators of cationic polymerizations . The mechanism involves photolysis of the iodonium salt to form an aryl radical and an iodoarene radical cation leading to the formation of Brønsted acids, which start the polymerization. − With certain monomers, such as THF and 1,3-dioxolane, radical-chain chemistry of the aryl radicals with the monomer can lead to monomer-derived cations that are also capable of starting polymerization. − …”

“…However, the use of iodonium salts in applications such as photocurable coatings and composites, printing inks, and stereolithography is limited by the weak absorption of these salts in the visible region. − Therefore, there has been considerable interest in developing iodonium-based systems for visible-light-induced cationic polymerization (VLICP). − A number of approaches have been employed including the modification of iodonium structure to extend the λ max and the use of photosensitizers that can do photoinduced electron transfer to the iodonium salt. Another approach involves using light to initiate a reductive radical chain reaction of the iodonium salt with an additive (co-initiator) to form reactive cations. − …”