In this study, star-shaped PLLA was synthesized by using 2, 3 and 4 OH group-contained amine initiators to improve hydrophilicity and to decrease crystallinity of poly(L-lactide) (PLLA) drug delivery system. Tin(II) 2-ethylhexanoate (Sn(Oct)2) was selected as a polymerization catalyst and N-butyldiethanolamine (NBDA), triethanolamine (TEA), N,N,N',N'-tetrakis(2-hydroxyethyl)ethylendiamine (TEED) were used as initiators. PLLA polymerization was carried out through bulk polymerization and solution polymerization. The synthesized polymers were characterized by differential scanning calorimetry (DSC) and crystal morphology and crystal growth behavior were confirmed by X-ray diffraction (XRD) and polarized optical microscopy (POM). Star-shaped PLLA synthesized by bulk polymerization showed lower melting point and crystallinity, smaller crystal size, and slower crystal growth rate than linear PLLA. The PLLA synthesized by solution polymerization showed no significant difference in melting point, crystallinity, and crystal growth rate between linear PLLA and star-shaped PLLA.

Poly(L-lactide)(PLLA)의 약물 전달 시스템에서의 낮은 친수성과 높은 결정성을 향상시키기 위하여 2, 3, 4개의 OH기를 가지는 아민계 개시제를 이용하여 star-shaped PLLA를 벌크와 용액 중합으로 합성하였다. Sn(Oct)2를 중합촉매로 개시제로는 N-butyldiethanolamine, triethanolamine, N,N,N',N'-tetrakis(2-hydroxyethyl)ethylendiamine을 사용하였다. 합성된 고분자는 시차주사열량계, X-선 회절, 편광광학현미경을 통해 결정 형태와 결정 성장 거동을 확인하였다. 벌크 중합으로 합성된 star-shaped PLLA는 선형 PLLA와 비교했을 때 녹는점, 결정성이 낮았으며 결정의 크기가 작으며 결정 성장 속도가 느렸다. 용액 중합으로 합성된 PLLA는 벌크 중합보다 선형 PLLA와 star-shaped PLLA의 녹는점, 결정성, 결정 성장 속도가 차이가 크지 않았다.

Keywords: star-shaped poly(L-lactide), crystal morphology, crystal growth behavior