Novel biodegradable ester-based polymer blends

We have found, within the polyester family, interesting and potentially useful patterns of three-component compatibility. The bacterially produced biodegradable polyester, poly(hydroxybutyrate) (PHB) and its copolymers with hydroxyvalerate (HV) together with polymers such as cellulose acetate butyrate (CAB), polycaprolactone, poly(lactic acid), and a series of high-molecular-weight, non-crystallizable ester-based plasticisers have been identified as possible candidates in the production of blends in which aspects of performance can be varied with a degree of independence of cost. The compatibility ranges can be conveniently represented in the form of triangular graphs, with the relative weight fraction, or percentage, being represented along each of the three axes. The extent to which the modulation of the physical properties in general, but the stability in various environments in particular, is possible by the formation of three-component blends, such as those formed between P(HB-HV), cellulose acetate butyrate and poly(alkylene adipate) plasticisers, is discussed.