Comparative life cycle studies on poly(3-hydroxybutyrate)-based composites as potential replacement for conventional petrochemical plastics.

A cradle-to-grave environmental life cycle assessment (LCA) of a few poly(3-hydroxybutyrate) (PHB) based composites has been performed and was compared to commodity petrochemical polymers. The end products studied are a cathode ray tube (CRT) monitor housing (conventionally produced from high-impact polystyrene, HIPS) and the internal panels of an average car (conventionally produced from glass-fibers-filled polypropylene, PP-GF). The environmental impact is evaluated on the basis of nonrenewable energy use (NREU) and global warming potential over a 100 years time horizon (GWP100). Sugar cane bagasse (SCB) and nanoscaled organophilic montmorillonite (OMMT) are used as PHB fillers. The results obtained show that, despite the unsatisfying mechanical properties of PHB composites, depending on the type of filler and on the product, it is possible to reach lower environmental impacts than by use of conventional petrochemical polymers. These savings are mainly related to the PHB production process, while there are no improvements related to composites preparation. SCB-based composites seem to be environmentally superior to clay-based ones.

Bio-based polymeric composites comprising wood flour as filler.

The increasing effort on development of bio-based polymeric materials in recent years is motivated by the basic concept of meeting the sustainability criteria for industrial development in the third millennium. Within this framework, our research group is currently involved in assessing the potentiality of some agro-industrial overproduction and byproducts in the formulation of eco-compatible bio-based polymeric materials displaying, among others, the propensity to biodegrade under controlled environment conditions. In the present work, beech wood flour (Bwf) composites were prepared from plasticized poly(3-hydroxybutyrate) (PHB). The type of plasticizer [tri(ethylene glycol) bis(2-ethylhexanoate) (TEGB) and poly(ethylene glycol) (PEG200)] and the amount [5 and 20 wt %] were selected as independent variables in a factorial design. Thermal and mechanical properties of 90 wt % PHB composites were investigated. Incorporation of PEG200 was found to compromise thermal stability of PHB as demonstrated by the higher decrease on the onset decomposition temperature (T(d)) and the drop in its average molecular weight (M(w)). The present study underlines the fact that TEGB/PHB/beech wood flour composites can be optimized to obtain new materials for disposable items.