In this study, we prepared silica nanoparticles with methacrylate groups on their surface by two-step modification process. Silica particles were first silanized with (3-trimethoxysilylpropyl)diethylenetriamine (TPDT), after that Michael addition reaction was performed between N-H groups on the TPDT modified silica surface with acrylate groups of 3-(acryloyloxy)-2-hydroxypropylmethacrylate (AHM). We also used pristine silica and 3-methacryloxypropyltrimethoxysilane (MPTMS) modified silica as fillers to make nanocomposites with urethane acrylate resin. We studied effects of above mentioned silica types on the mechanical properties of UV-cured nanocomposites. We found Young's modulus values of UV cured resin, nanocomposites with 0.5 wt% pristine silica, with 0.5 wt% MPTMS modified silica and with 0.5 wt% TPDT/AHM modified silica were 386.6, 433.6, 462.4 and 517.6 MPa, respectively. The highest modulus was found in the nanocomposite of 0.5 wt% TPDT/AHM modified silica.

본 연구에서는 (3-trimethoxysilylpropyl)diethylenetriamine(TPDT)으로 실리카 표면에 N-H기를 도입하여 Michael 부가 반응이 가능한 3-(acryloyloxy)-2-hydroxypropylmethacrylate(AHM)과 반응시킴으로써 methacrylate기를 도입하였다. 또한 순수 실리카와 3-methacryloxypropyltrimethoxysilane(MPTMS)만으로 개질된 실리카를 충전제로 사용하여 urethane acrylate계 수지와 광중합법으로 나노복합체를 제조하였다. UV 수지 중합체와 순수 실리카, MPTMS로 개질된 실리카 및 TPDT/AHM으로 개질된 실리카를 각각 0.5 wt% 포함하는 나노복합체들의 탄성률 값이 386.6, 433.6, 462.4 및 517.6MPa로 TPDT/AHM으로 개질된 실리카 나노복합체의 탄성률이 가장 우수함을 확인하였다.

Keywords: silica; surface modification; michael addition reaction; UV-curing; mechanical property