Crystallization and morphology studies of biodegradable poly(ε-caprolactone)/silica nanocomposites

Biodegradable poly(epsilon-caprolactone) (PCL)/silica nanocomposites at various silica loadings were prepared via direct melt compounding method in this work. Scanning electron microscopy observation indicated that when the silica content was < 3 wt%, the nanoparticles dispersed evenly in the PCL matrix and exhibited only aggregates with particle size of less than 100 nm. The results of nonisothermal melt crystallization showed that the crystallization peak temperature was higher in the nanocomposites than in neat PCL; moreover, the overall crystallization rate was faster in the nanocomposites than in neat PCL during isothermal melt crystallization. Both nonisothermal and isothermal melt crystallization studies suggested that the crystallization of PCL was enhanced by the presence of silica and influenced by the silica loading. The effect of silica on the crystallization behavior was twofold: the presence of silica may provide heterogeneous nucleation sites for the PCL crystallization while the aggregates of silica may restrict crystal growth of PCL. However, the crystal structure of PCL remained almost unchanged despite the presence of silica in the nanocomposites. POLYM. COMPOS., 2013. (c) 2012 Society of Plastics Engineers