Barrier and mechanical properties of poly(caprolactone)/organoclay nanocomposites,

In this study, biodegradable poly(caprolactone) (PCL) hybrids with two types of organoclays: Cloisite 30B (30B) and Cloisite 93A (93A) have been prepared by melt mixing and their barrier performance to air permeation and mechanical properties were investigated. The hybrids of PCL/30B were found to be nanocomposites resulted from the strong interaction between organic modifier of 30B and PCL and those of PCL/93A were microcomposites. The barrier properties to air were much more improved in PCL/30B nanocomposites than pure PCL or PCL/93A microcomposites with the organoclay content. The barrier behaviour of PCL/organoclay nanocomposites could be approximately described by a theoretical model developed for composites. The similar trend was shown for the mechanical properties improvement that the reinforcement of organoclay 30B in nanocomposites is more significant than 93A in microcomposites. Both tensile modulus and tensile strength were increased by mixing low amount of organoclay without much loss of strain at break as compared to pure PCL. The significant improvements in both barrier and mechanical properties in nanocomposites could be attributed to the fine dispersion state of organoclay 30B platelets in PCL matrix and the interaction between organic modifier of 30B and matrix molecules.