In this study, we modified silica nanoparticles (Aerosil 200<sup>®</sup> Evonik Degussa) with (3-trimethoxysilylpropyl)diethylenetriamine (TPDT) silane coupling agent which has one primary and two secondary amino groups in a molecule, to introduce amino groups on the silica particle surface. After modification of silica, we used acrylate group containing 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHM) to introduce free radical polymerizable methacrylate groups by aza-Michael addition reaction. Using pristine silica, TPDT modified silica or AHM-TPDT modified silica as fillers, we prepared nanocomposites by UV-curing with isobornyl acrylate (IBOA) as reactive diluent, aliphatic difunctional urethane acrylate (M.W. = 5,200 g/mol, SC 2404, Miwon Specialty Chemical, Korea) as oligomer, and 1-hydroxycyclohexyl phenyl ketone (M.W. = 204.3, Irgacure 184, Ciba Specialty Chemicals) as photo-initiator. We studied effects of various types of modified fillers and their contents on mechanical properties of UV-cured nanocomposites.<br/>The reaction scheme is shown in Scheme 1. We found change of Tg by incorporation of silica particles into the polymer matrix, from 47.4 °C without any filler to 50.0 °C with 0.5 wt% AHM-TPDT modified silica. Therefore, AHM-TPDT modified silica particles act as multi-crosslinking sites in UV-cured nanocomposite.

Effects of surface modification of silica nanoparticles on the mechanical properties of UV-curable silica/polyurethane acrylate nanocomposites

251st National Meeting (2016)

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