title: Unique Curing Properties through Living Polymerization in Crosslinking Materials: Polyurethane Photopolymers from Vinyl Ether Building Blocks.
abstract: Photopolymers with unique curing capabilities were produced by combining living cationic polymerization with network formation and restricted polymer motion. A vinyl ether diol was synthesized as a functional building block and reacted with isophorone diisocyanate to form a highly functionalized vinyl ether polyurethane as a model system with high crosslinking ability. When using a cationic photoinitiator, fast polymerization is observed upon short UV irradiation. Curing proceeds in the absence of light and under ambient conditions without oxygen inhibition. Cationic active sites become trapped dormant species upon network-induced vitrification and surprisingly remain living for several days. The polymerization can be reactivated by additional UV irradiation and/or raised temperature. The curing behavior was studied in detail by using UV and FT-NIR coupled rheology and photo-DSC to simultaneously study spectroscopic and mechanical information, as well as thermal effects.
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz (Germany); Henkel AG & Co. KGaA, Adhesive Research, Henkelstraße 67, 40191 Düsseldorf (Germany).
authors.forename: Stefan
authors.initials: S
authors.lastname: Kirschbaum
authors.forename: Katharina
authors.initials: K
authors.lastname: Landfester
authors.forename: Andreas
authors.initials: A
authors.lastname: Taden
keywords: curing; living crosslinking; photochemistry; polymerization; vinyl ethers