Environmental Degradation of Polyester Blends Containing Atactic Poly(3-hydroxybutyrate). Biodegradation in Soil and Ecotoxicological Impact

Abstract

The degradation of poly[(R,S)-3-hydroxybutyrate], a-PHB, binary blends with natural PHB (n-PHB) and poly(L-lactic acid), PLLA, respectively, has been investigated in soil. In such a natural environment, a-PHB blend component was found to biodegrade. The degradation of a-PHB-containing blends proceeded faster than that of respective plain n-PHB and PLLA. The molecular weight decrease of the n-PHB component was higher, while the same rate of bioerosion of both components was observed for the a-PHB/n-PHB binary blend. For the a-PHB blend with PLLA, the weight loss was accompanied by blend composition changes and the decrease of a-PHB content. However, the PLLA molecular weight decrease was lower in the blend in comparison with the plain PLLA sample. The increase of the number of microorganisms particularly observed for the soil where binary blends were incubated indicates that microbial degradation of a-PHB takes place. The terrestrial plant growth test (cress and barley) demonstrates no environmental toxicity of the materials studied.

Application of Poly(hydroxyalkanoate) In Food Packaging: Improvements by Nanotechnology

“…As a rule, blending has been known as a strategy of tailoring the properties of PHAs while maintaining biodegradability 67 . Blending of PHB and PHBV with other biopolymers including starch [89][90][91] , thermoplastic starch, PLA 92 , PCL 13,93,94 , and polyvinyl alcohol (PVOH) 91 are reported. In addition, there are some reports on PLA blending with different polymers e.g.…”

Biodegradation of PP and PE Blended with PHBV in Soil Samples

“…The authors conclude that the addition of a-PHB accelerates the process of degradation of natural PHB, and in the presence of mineral fertilizer, the erosion of all samples occurs faster than that without fertilizer. 30 Weng et al 31 studied the biodegradation of the P(3HB,4HB)/PLA blends with different compositions at different depths in real soil environments. The degraded residues of various samples demonstrated that P(3HB,4HB) was biodegraded into small molecular weight acids caused by erosion of microorganisms.…”

Polyhydroxyalkanoates (PHAs) for food packaging

“…Blending with other biopolymers has been considered as a way of tailoring the properties of PHAs while maintaining biodegradability (Ohashi et al, 2009). Mixtures of PHB and PHBV with other biopolymers have been reported by numerous authors and the polymers mentioned in recent studies include starch (Godbole et al, 2003;Reis et al, 2008;Zhang and Thomas, 2010), thermoplastic starch , poly-(L-lactic acid) (PLLA) (Furukawa et al, 2006;Rychter et al, 2006), polycaprolactone (PCL) (Lovera et al, 2007;Sanchez-Garcia et al, 2008), and polyvinyl alcohol (PVOH) (Olkhov et al, 2003).…”