Blends based on biodegradable poly(caprolactone) with outstanding barrier properties for packaging applications: The role of free volume and interactions

In order to improve the poor barrier properties of poly(caprolactone) (PCL) this polymer was blended with poly (hydroxy ether of bisphenol A) (PH). The thermal properties, as well as the free volume of the system were analysed. The incorporation of PH significantly reduces the permeability of poly(caprolactone) to oxygen, carbon dioxide and water vapour. This reduction is linked to the free volume fraction, the thermal properties and the balance of interactions between polymers and penetrants. The outstanding results obtained allow to expand the applications of poly(caprolactone) in the packaging sector. The aim of this work is to achieve a better understanding of the factors that are involved in the barrier character improvement of poly(caprolactone) that could be extended to other biodegradable polymers.