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Epoxy networks reinforced with TiO 2 generated by nonhydrolytic sol–gel process: A comparison between in situ and ex situ syntheses to obtain filled polymers
Author(s) -
Morselli Davide,
Bondioli Federica,
Sangermano Marco,
Messori Massimo
Publication year - 2015
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.24007
Subject(s) - materials science , epoxy , cationic polymerization , monomer , trifluoromethanesulfonate , polymer , nanoparticle , nanocomposite , composite material , polymerization , chemical engineering , polymer chemistry , organic chemistry , catalysis , nanotechnology , chemistry , engineering
Titania nanoparticles suspended in benzyl alcohol (BzOH) were generated by nonhydrolytic sol–gel process starting from titanium tetrachloride. The obtained suspensions were mixed with 3,4‐epoxycyclohexylmethyl‐3,4‐epoxycyclohexanecarboxylate epoxy resin, and the formulations were cured in the presence of ytterbium(III) trifluoromethanesulfonate as cationic initiator. The thermally activated cationic ring‐opening polymerization produced a three‐dimensional network in which the suspending medium BzOH was covalently linked to the epoxy network according to the “activated monomer” mechanism during the propagation step. The presence of titania nanoparticles resulted in a reinforcing and stiffening effect due to both their hydrodynamic effect and, most important, a significantly higher cross‐linking density of the composite material with respect to the unfilled epoxy resin. A comparison with similar composites obtained by physical incorporation of preformed titania particles was also reported in order to compare the in situ and ex situ filler generation for preparing nanocomposites. POLYM. ENG. SCI., 55:1689–1697, 2015. © 2014 Society of Plastics Engineers