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UV‐Induced [2+2] Grafting‐To Reactions for Polymer Modification of Cellulose
Author(s) -
Conradi Matthias,
Ramakers Gijs,
Junkers Tanja
Publication year - 2016
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.201500484
Subject(s) - polymer chemistry , grafting , cellulose , acrylate , benzaldehyde , chain transfer , polymerization , polymer , contact angle , materials science , chemistry , radical polymerization , organic chemistry , copolymer , catalysis , composite material
Benzaldehyde‐functional cellulose paper sheets have been synthesized via tosylation of cellulose (Whatman No 5) followed by addition of p ‐hydroxy benzaldehyde. Via UV‐induced Paterno–Büchi [2+2] cycloaddition reactions, these aldehyde functional surfaces are grafted with triallylcyanurate, trimethylolpropane allyl ether, and vinyl chloroacetate. In the following, allyl‐functional polymers (poly(butyl acrylate), pBA, M n = 6990 g mol −1 , Đ = 1.12 and poly( N ‐isopropyl acrylamide), pNIPAAm, M n = 9500 g mol −1 , Đ = 1.16) synthesized via reversible addition fragmentation chain transfer polymerization are conjugated to the celloluse surface in a UV‐induced grafting‐to approach. With pBA, hydrophobic cellulose sheets are obtained (water contact angle 116°), while grafting of pNIPAAm allows for generation of “smart” surfaces, which are hydrophilic at room temperature, but that become hydrophobic when heated above the characteristic lower critical solution temperature (93° contact angle). The Paterno–Büchi reaction has been shown to be a versatile synthetic tool that also performs well in grafting‐to approaches whereby its overall performance seems to be close to that of radical thiol‐ene reactions.