Novel sinthetic blends between bacterial polyesters and acrylic rubber: a study on enzymatic biodegradation

The biodegradability of a multicomponent system based on biotechnological occurring polyester (poty(/3-hydroxybutyrate-co-/3-hydroxyvalerate) (PHBV)) with inclusion of acrylate elastomcr (potybutylacrylate) (PBA) was investigated. A bacterium which produced extracellular enzymes that degrades PHBV even when blended with PBA was isolated and tentatively designated as Aureobacterium saperdae. It was observed, by morphological investigation, that, while the bacterial degradation was permitted for PBA content of 20% by weight, it was inhibited lbr PBA content of 30%, owing to the occurrence of a rubbery layer that prevents to the bacteria an easy accessibility in the PHBV-rich regions. In fact, owing the bacterial growth, only PHBV was metabolized, whereas no degradation of PBA was detected for blend samples. It was confimaed that the degradation proceeded via surface erosion of PHBV also in the blends, Finally. mechanical tests on PHBV/PBA specimens as a function of degradation extent have shown different behavior of the blends at different the PBA content. Thermal analysis of blends and PHBV has been reported, too