Light-induced polymerisation of photoinitiator-free vinyl ether/maleimide systems

Abstract

SUMMARY: The photo-induced copolymerisation of electron donor/electron acceptor monomers has been studied by real-time infrared spectroscopy. With stoichiometric maleimide-vinyl ether mixtures, the reaction was found to proceed within seconds upon UV exposure. For systems with an excess of vinyl ether, the two monomers disappeared at essentially the same rate, to generate an alternating copolymer. In such photoinitiator-free systems, the initiating radicals are mainly formed by hydrogen abstraction by the excited maleimide molecules. Highly crosslinked polymer networks have been obtained by light-induced copolymerisation of bismaleimide and divinyl ether monomers. One of the distinct characteristics of this type of radical-induced polymerisation, beside the absence of any added photoinitiator, is that it is less sensitive to oxygen inhibition than the conventional UV-curable acrylate resins.

Photo-initiated chemical vapor deposition as a scalable particle functionalization technology (a practical review)

“…Moreover, commonly used photo-initiators are rather expensive or toxic, if not both [70]. More recently, the trend is in the direction of photo-initiator-free reaction solutions [58,59]. The terms sensitizer and photo-initiator have been interchanged for a long time now [55].…”

“…Extensive work on the subject has been done around the 1940s [55,56]. Recently, the photochemistry trend has resurrected vividly, often using acrylates or thiolene acrylates as monomers [38,42,57,58,59,60,61,62,63,64]. The field has garnered renewed interest in the two last decades, mainly due to its application to many fields such as coatings and adhesives.…”

Highly Sensitive ^|^alpha;-Acyloxymethacrylate Cross-linking Agents with High Curability in the Presence of Atmospheric Oxygen

“…As attempts to reduce polymerization inhibition by oxygen, an approach based on initiators [3] and an approach based on polymerizable compounds [4] have been reported.…”

ESR and photopolymerization study of polymerizable benzophenone photoinitiators containing functional maleimide groups

“…Significant work has been reported dealing with the use of N-substituted maleimides (MIs) as photoinitiators for free-radical polymerization [5,[17][18][19][20][21][22][23][24][25][26][27]. In each of these cases, the MIs participate in producing radical species and will also be consumed by the copolymerization with the photo-curing resin [28], i.e., they do not remain in the final film as an extractable or photoreactive contaminant [22].…”

“…In each of these cases, the MIs participate in producing radical species and will also be consumed by the copolymerization with the photo-curing resin [28], i.e., they do not remain in the final film as an extractable or photoreactive contaminant [22]. Meanwhile, it is well known that maleimide and its derivatives can polymerize to give thermally stable polymers, and the copolymerization with various vinyl monomers has been verified to improve the thermal properties of the polymers, especially for N-aryl MIs [29].…”