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The aim of this work was to obtain biodegradable polymeric systems based on poly(hydroxybutyrate) (PHB) for use in the controlled release of agrochemicals and to analyze the relationship between the properties of polymers and the rates of release of active compounds. Two types of systems were obtained: one using nitrogen, phosphorous, and potassium (NPK) fertilizer directly mixed within the polymer matrix and another with the fertilizer previously incorporated in bentonite (Bent) and mixed with the polymer. The systems were obtained by melt processing and then evaluated by their properties. The release of the active compounds was analyzed by conductometric analysis using an aqueous solution as release medium for 240 hours. The obtained results were correlated with the biodegradation process of PHB. All of the systems presented a significant reduction in the active compounds released to the environment as compared with the direct application of NPK. The PHB/NPK systems showed a release of up to 37% of the compounds, while the PHB/m‐Bent showed greater control, with a release between 4% and 11% after 240 hours. In addition, the properties of the polymer systems presented a direct relationship with the rate of active compounds released. The type of production process, properties, and biodegradability indicate interesting potential of these systems for application in the controlled release of active compounds.

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In this study, a nanocomposite based on a biodegradable polymer poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) reinforced by triethylene glycol mono-n-decyl ether (C 10 E 3 ) non-ionic organoclay (C 10 E 3 -Mt) was prepared. The morphology and the thermal and mechanical properties of PHBV/C 10 E 3 -Mt were compared with those of PHBV nanocomposites prepared using commercial organically modified montmorillonite Cloisite ® 30B (OMt) and raw montmorillonite (Mt). Nanocomposites with 3 wt% nanoparticles were obtained by melt processing. The high level of dispersion with improved interfacial interactions between OMt and polymer led to an increase in the thermal stability and modulus of PHBV. However, this nanocomposite presented a lower strain before fracture, typical of brittle behavior. The transmission electron microscopy and wide angle X-ray diffraction results revealed a significant increase in the interlayer spacing of clay for the PHBV/C 10 E 3 -Mt nanocomposite, which was favored by the wide expansion of the platelets of the starting non-ionic organoclay. This characteristic of C 10 E 3 -Mt, together with its hydrophobic behavior, allowed its easy incorporation in the PHBV matrix, thus improving the processing and maintaining a high modulus with increased material toughness.

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