Biodegradable polycaprolactone (PCL) and four different types of starch were blended and their properties were examined. The PCL/oxydized starch (OS) and PCL/high-amylose corn starch (HACS) blends showed higher tensile strength and elongation than the PCL/corn starch (CS) blends, and the mechanical properties of the PCL/amylopectine (AP) blends were similar to those of the PCL/CS blends. The tensile strength and percentage elongation of the PCL/starch blends were similar to those of LDPE, as long as the starch content was around 30%. However, when the starch content was increased to 50%, the mechanical Properties of the PCL/starch blends were sharply decreased. Grafting of MMA onto starch was enhanced when the MMA concentration was high and water was used as the dispersant. The higher the grafting percentage of PMMA onto starch, the lower the biodegradability of PMMA grafted starch (Starch-g-PMMA). Not only the mechanical properties such as the tensile strength and percentage elongation but also the water resistance of the PCL/Starch-g-PMMA blend was higher than those of the PCL/CS blends.

폴리카프로락톤(PCL)과 4종류의 전분을 블렌딩한 생분해성 플라스틱과 메틸메타크릴레이트를 전분에 그라프팅시킨 PMMA grafted starch (Starch-g-PMMA)를 PCL과 블렌딩한 PCL/Starch-g-PMMA 블렌드의 물성을 조사하였다. PCL/산화전분(OS) 블렌드, PCL/아밀로즈를 많이 함유한 전분 (HACS) 블렌드는 PCL/옥수수전분(CS) 블렌드보다 나은 기계적 물성을 보였으며, PCL/아밀로펙틴 (AP) 블렌드는 PCL/CS 블렌드와 유사한 물성을 나타내었다. 블렌드내 전분의 함량이 30%일 때 LDPE수준의 인장강도와 신장율을 나타내었으나 전분의 함량이 50%에 이르면 물성이 급격히 저하되었다. 한편 MMA의 농도가 높을수록, 그리고 H₂O : DMF (1:1) 혼합용매에 비하여 순수한 물을 분산매로 사용하였을 때 더 많은 PMMA가 전분에 그라프팅되었다. 또 PMMA가 전분에 더 많이 그라프트될수록 Starch-g-PMMA의 생분해도는 감소하였다. PCL/Starch-g-PMMA 블렌드는 PCL/CS 블렌드에 비하여 더 우수한 인장강도, 신장율을 나타내었으며 내습성도 개선되었다.

Keywords: starch; starch graft derivatives; biodegradability; PMMA grafted starch; polycaprolactone (PCL)