This study aimed to evaluate the thermal behavior of polyhydroxybutyrate (PHB)/polypropylene grafted with maleic anhydride (PP‐g‐MA) blends and PHB/PP‐g‐MA/vermiculite bionanocomposites submitted to the biodegradation test according to ASTM G 160‐03. The blends and bionanocomposites were prepared by melt intercalation method using a single screw extruder, and then, compression molded. The thermal analyzes were performed by thermogravimetry (TG) and differential scanning calorimetry. It was verified the decrease of onset degradation temperature and the melting temperature mainly after 86 days of exposure to the simulated soil. This behavior was more pronounced in bionanocomposites because of interactions between the maleic anhydride groups and the clay favoring biodegradation, making the systems more amorphous and propitious to the attack of microorganisms. POLYM. ENG. SCI., 56:555–560, 2016. © 2016 Society of Plastics Engineers

In this work, nanocomposites were developed and evaluated using high-density bio polyethylene (BPEAD)/Cloisite 20A (3 and 6%)/commercial antimicrobial additive (0,5 and 1%) containing 1% of zinc pyrithione dispersed in vinyl acetate (EVA). The samples were prepared in a single screw extruder using the melt intercalation technique and then by flat extrusion to obtain the films. X-ray diffraction (XRD) showed an increase in basal spacing and exfoliation of the structure of some films. The Fourier Transform Infrared Spectroscopy (FTIR) analysis illustrated the main functional groups for BHDPE and EVA. Thermal analysis indicated that BHDPE degradation did not change with organoclay addition, but crystallinity increased. The mechanical properties showed an increase in the elastic modulus and a decrease in maximum tensile strength. This work contributes to the development and improvement of the natural properties of BHDPE in order to enlarge its applications.

In this study, the biodegradation process of PHB/PP-g-MA/clay bionanocomposites was evaluated. Films with compositions of 5% PP-g-MA and 3% clay (BIO5); and 2.5% PP-g-MA and 3% clay (BIO2,5) were prepared. The biodegradation test was performed according to ASTM G 160-03 for a period of 86 days. The evaluation of the degradation was carried out by optical microscopy (OM), weight loss, FTIR and XRD. The bionanocomposites showed change of color and appearance of cracks. As the mass loss, the BIO2,5 system presented loss of 22.5%, and the BIO5, of 25.9%, for 86 days of exposure in simulated soil. It was also observed by FTIR, a marked reduction in the intensity of the corresponding band to the C = O groups, indicating that microbial attack promoted cleavage of bonds of the ester group. By XRD, there was a decrease in the intensity of the peaks and enlargements thereof with increasing exposure time, demonstrating the biodegradation behavior of bionanocomposites.