Blends of bacterial poly(3-hydroxybutyrate) with synthetic poly(3-hydroxybutyrate) and poly(epichlorohydrin): transport properties of carbon dioxide and water vapour

The water vapour and carbon dioxide transport properties have been measured of bacterial (isotactic) poly(3-hydroxybutyrate) (iPHB) and its blends wit h synthetic (atactic) PHB (aPHB) and poly(epichlorohydrin) (PECH) have been measured. The purpose of this work is to study the transport properties of iPHB blends with a miscible second polymer, intended as a polymeric toughe ner that does not impair the original iPHB biodegradability. Thus, only iPH B rich blends containing up to 40% of aPHB or PECH were considered. The eff ect of aPHB on the blends is to increase the sorption and permeability with respect to pure iPHB due to the reduction in the level of crystallinity, w hile PECH tends to decrease the water and carbon dioxide solubilities of th e blend. The blends have essentially the same permeability to CO2, although the water transmission rates are lower for the iPHB/PECH system. (C) 2000 Elsevier Science Ltd. All rights reserved.