Poly(ε-caprolactone) (PCL)/Halloysite nanotube(HNT) 나노복합체의 형상기억특성, 약물방출특성 및 분해 특성

Abstract

Naturally available halloysite nanotubes (HNTs) with hollow nanotubular structures were used as reinforcement in poly(ε-caprolactone) (PCL). The PCL/HNT nanocomposite film and the corresponding drug-loaded film were prepared by solution blending followed by solvent casting. TEM and SEM analysis showed that the HNTs were dispersed uniformly on the nanoscale throughout the PCL matrix. Differential scanning calorimetry, tensile test, and dynamic mechanical analysis (DMA) showed that, with increasing HNT content in the nanocomposites, the melting temperature and PCL crystallinity was decreased while the glass transition temperature, tensile modulus and strength increased without sacrificing the ductility of PCL. DMA result also showed the presence of a rubbery plateau above the melting temperature of the PCL/HNT nanocomposites, and the moduli at the plateau region increased with increasing HNT content in the nanocomposites, implying that the PCL/HNT nanocomposites formed a physically crosslinked structure. The PCL/HNT nanocomposites and the nanocomposite loaded with 10wt% theophylline drug exhibit a good thermally-triggered shape memory behavior with a shape recovery ratio of 90%, In vitro drug release studies using theophylline as a model drug showed a slower and more continuous release for the nanocomposite films in comparison with pure PCL film, and the drug-delivery cumulative release was proportional to the amount of HNT in the nanocomposites. It was also observed that HNT can increase hydrolytic degradation rate of the PCL matrix.