Improving transparency of incompatible polymer blends by reactive compatibilization

An opaque polylactide/poly(ethylene-co-vinyl alcohol) (PLA/EVOH 90/10 w/w) blend was made transparent by reactive compatibilization. In the presence of a multifunctional epoxy compound and zinc stearate, the dispersed domain size of EVOH in the blend and its distribution decreased significantly based on the morphological and dynamic light scattering analysis. Consequently, the light transmission at 700 nm increased from 9.3% for the incompatibilized sample to 83.5% for the compatibilized sample. A significant difference in the transparency of the samples can also be confirmed by naked eye. Meanwhile, the barrier property to water vapor of the compatibilized blend was maintained. The transparent PLA blend with improved water vapor barrier property has potential application in the packaging industry. ⺠An opaque PLA/EVOH blend is made transparent by reactive compatibilization. ⺠The compatibilizer is the combination of an epoxy compound and a catalyst. ⺠The dispersed domain size and its distribution decreased significantly. ⺠The barrier property to water vapor of the compatibilized blend was maintained.