The widespread application of poly(3-hydroxybutyrate) (PHB) in the food packaging and biomedical fields has been hindered by its high brittleness, slow crystallization, poor thermal stability, and narrow processing window. To overcome these limitations, a mixture of biodegradable and biocompatible plasticizers was used to modify PHB. Epoxidized soybean oil (ESO), acetyl tributyl citrate, poly(ethylene glycol) 4000 (PEG4000), and poly(ethylene glycol) 6000 (PEG6000) were tested to improve PHB melt processing and to achieve balanced thermal and mechanical properties. These plasticizers increased the flexibility and decreased the melt viscosity, improving the processability. The tensile strength was maintained within the limit of experimental error for ESO and decreased slightly (6-7%) for the other plasticizers. PEG6000 and ESO delayed the decomposition process of PHB. The plasticizers did not hinder the crystallization, and poly(ethylene glycol)s increased the crystallinity. The change in the interplanar distance and crystallite size, correlated with lamellar stack dimensions, gave more information on the plasticizers' effects in PHB. The blend with 5 wt % ESO was considered suitable for the fabrication of marketable PHB films. This study showed that it is possible to tailor the rheological, thermal, and mechanical behavior of a commercial PHB through the addition of a second plasticizer.

New slow-release agrochemical formulations based on cross-linked poly(acrylic acid) hydrogels and liquid fertilizers (LF) were prepared by free radical copolymerization of acrylic acid (AA) and N,N′-methylenebisacrylamide directly in the LF solution. Two NPK liquid fertilizer compositions containing urea and potassium and ammonium phosphates were employed. For comparison, AA was also polymerized under identical conditions in distilled water. The resulting products were characterized by FTIR spectroscopy and scanning electron microscopy, and their water absorption and slow-release properties were determined. The results showed that the swelling degree (SD) of the hydrogels synthesized depended on the overall concentration of reactants (monomers and initiator), LF composition and cross-linking agent, and initiator concentrations. By appropriately combining these reaction parameters, superabsorbent hydrogels with SDs in distilled water ranging from a few hundred to 1000 g of water/g of xerogel can be obtained. The fertilizer-containing hydrogels displayed slow-release properties in still distilled water at room temperature. These slow-release formulations will be tested in the future for their effect on corn and sunflower crops.

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Bone regeneration is a claim challenge in addressing bone defects with large tissue deficits, that involves bone grafts to support the activity. In vitro biocompatibility of the bacterial cellulose-modified polyhydroxyalkanoates (PHB/BC) scaffolds and its osteogenic potential in critical-size mouse calvaria defects had been investigated. Bone promotion and mineralization were analyzed by biochemistry, histology/histomorphometry, X-ray analysis and immunofluorescence for highlighting osteogenesis markers. In summary, our results showed that PHB/BC scaffolds are able to support 3T3-L1 preadipocytes proliferation and had a positive effect on in vivo osteoblast differentiation, consequently inducing new bone formation after 20 weeks post-implantation. Thus, the newly developed PHB/BC scaffolds could turn out to be suitable biomaterials for the bone tissue engineering purpose.