Ti(dibenzoylmethane)₂(O-i-Pr)₂ 합성과 L-락티드 개환중합

Ti(dbm)(2)(O-i-Pr)(2) catalyst was synthesized using Ti(O-i-Pr)(4) and dibenzoylmethane(dbm) to develop a catalyst for the polymerization of L-lactide. The L-lactide polymerization behaviors of Ti(dbm)(2)(O-i-Pr)(2) catalyst was observed with varying molar ratio of L-lactide/catalyst and polymerization time. The conversion and molecular weight increased with increasing L-lactide/catalyst molar ratio. Ti(dbm)(2)(O-i-Pr)(2) catalyst was found to have a low catalytic activity because of the presence of a phenyl group in the catalyst and interfering with the lactide insertion during the polymerization reaction. Benzyl alcohol as an initiator resulted in a significant reduction in conversion of Ti(dbm)(2)(O-i-Pr)(2) catalyst. The molecular weight of the obtained polymer was measured by DSC and GPC, and the molecular structure of PLA was confirmed by H-1 NMR. Poly(L-lactide)(PLA) 중합용 신규 촉매를 개발하기 위하여 $Ti(O-i-Pr)_4$와 dibenzoylmethane(dbm)을 이용, $Ti(dbm)_2(O-i-Pr)_2$ 촉매를 합성하였고 PLA 중합특성을 확인하였다. $Ti(dbm)_2(O-i-Pr)_2$ 촉매 PLA 중합 특성은 L-락티드/촉매 몰비 및 중합시간을 변화시키며 관찰하였다. L-락티드/촉매 몰비가 증가함에 따라 전환율과 분자량이 증가하였다. $Ti(dbm)_2(O-i-Pr)_2$ 촉매는 촉매 내 페닐기가 존재하여 중합 반응 중 락티드 삽입을 방해하기 때문에 촉매 활성이 낮은 것으로 판단된다. Benzyl alcohol을 개시제로 사용하여 중합한 결과 $Ti(dbm)_2(O-i-Pr)_2$ 촉매 전환율이 대폭 감소하였다. 얻어진 중합물은 DSC, GPC를 이용하여 녹는점과 분자량을 측정하였고 $^1H$ NMR로 PLA의 분자구조를 확인하였다.