High Performance Photo-curable Polymers and Oligomers Based on Novel Ring-opening Reactions of Oxetanes
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1005-Q02-04
High Performance Photo-curable Polymers and Oligomers Based on Novel Ring-opening Reactions of Oxetanes Tadatomi Nishikubo, and Hiroto Kudo Material and Life Chemistry, Kanagawa University, 3-27-1, Rokkakubashi, Kanagawa-ku, Yokohama, 221-8686, Japan ABSTRACT We found new reactions of oxetanes with many reagents such as acyl chlorides, silyl chlorides, phosphonyl chlorides, alkyl chlorides, aryl esters, thio esters, phosphonic acids, carboxylic acids, thiols, and phenols using suitable quaternary onium salts or crown ether complexes as catalysts. More recently, we also found an anionic ring-opening polymerization of certain oxetane monomers such as (3-methyl-3-hydroxymethyl)oxetane and (3-ethyl-3-hydroxymethyl)oxetane, which have hydroxyl groups, catalyzed by potassium tert-butoxide and 18-crown-6-ether complex, and an anionic ring-opening alternating co-polymerization of oxetane monomers with cyclic carboxylic anhydrides. These reaction systems have also been applied to the synthesis of new functional polymers. In this article, we would like to introduce the application of these reaction systems for the synthesis of high performance new photo-curable polymers and oligomers containing pendant or terminal (meth)acryloyl groups.
INTRODUCTION 3-Membered cyclic ether, oxiranes have high chemical reactivity due to their high strain energy. Therefore, epoxy resins, poly(glycidyl methacrylate)s, and their copolymers containing many pendant epoxide groups afford cross-linked gel products by addition reactions with certain crosslinking reagents such as polyfunctional-amines, -phenols, -carboxylic acids or carboxylic anhydrides using appropriate catalysts, or by ring-opening polymerizations using tertiary amines, imidazoles, Lewis acids or their complexes as catalysts. These reaction systems have been widely used1-6 in coatings, adhesives, encapsulants for semiconductor devices, print circuit boards, and solder resists. On the other hand, 4-membered cyclic ether, oxetanes have high strain energy (107 kJ/ mol) and have higher basicity than that of oxiranes. Hence, it is well known the cationic ring -opening polymerization of oxetanes proceeds7 smoothly in the presence of suitable cationic catalysts to produce the corresponding poly(ether)s. More than 15 years ago, Crivello et al., reported8, 9 the photo-initiated cationic polymerizations of oxetanes with appropriate photo-acid generators (PAG)s, which proceed very smoothly at room temperature. This system composed from polyfunctional oxetanes with PAG has been applied into high performance photo-curing
system by Sasaki10 and Kuriyama. Ukaji et al.,11 have also reported the application of the photo-initiated cationic polymerization system for three-dimensional photo-fabrication, because this system has high photochemical reactivity, excellent physical properties of the cured materials, and low volume shrinkage after the photo-crosslinking reaction. However, other useful organic reactions of oxetanes have not been reported. From these backgrounds, more than 15 ye
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