The miscibility of biodegradable poly(ethylene glycol) (PEG) blends with poly (ethylene-co-acrylic acid)(EAA) containing 8.9 mole% acrylic acid was studied by differential scanning calorimetry(DSC) and Fourier transform infrared (FT-IR) spectroscopy The melting point depression of crystalline PEG in the blend was observed. The equilibrium melting points of the blends were determined by the Hoffman-Weeks plot. A negative interaction parameter value (X₁₂=-0.54) of the blend at the temperature above the melting point (70 ℃) of PEG was estimated by using Nishi-Wang equation. Intermolecular hydrogen bonding interactions involving carboxylic acid group and ether oxygen which are responsible for the thermodynamic miscibility of the EAA/PEG blends are identified by FT-IR analysis. The results of both thermal and infrared spectroscopic analysis have substantiated that the EAA/PEG blends are highly mixed at the molecular level.

시차주사열분석(DSC) 및 푸리에변환 적외선(FT-IR) 분광분석을 이용하여 생분해성 폴리에틸렌글리콜(PEG)과 8.9mole%의 아크릴산을 함유하는 에틸렌-아크릴산 공중합체 (EAA)블렌드의 상용성을 조사하였다. 블렌드내의 결정성 PEG의 용점강하 현상이 일어났으며, Hoffman-Weeks 플롯으로부터 블렌드의 평형융점을 구하였다. PEG의 결정용융온도 이상인 70 ℃에서의 블렌드의 상호작용 파라미터, Ｘ₁₂=-0.54를 Nish-Wang식을 이용하여 구하였다. EAA/PEG 블렌드의 열역학적 상용성의 원인이 되는 분자간 수소결합이 아크릴산 카르복실기와 에테르기 사이에서 형성됨을 FT-IR 분석에 의하여 확인하였다.

Keywords: biodegradable poly(ethylene glycol); poly(ethylene-co-acrylic acid); negative interaction parameter; hydrogen bonding interractions; thermodynamic miscibility