RESUMEN

Given the global challenge of plastic pollution, the development of new bioplastics to replace conventional polymers has become a priority. It is therefore essential to achieve a balance in the performances of biopolymers in order to improve their commercial availability. In this topic, this study aims to investigate the morphology and properties of poly(lactic acid) (PLA)/ poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) (at a ratio of 75/25 (w/w)) blends reinforced with halloysite nanotubes (HNTs) and compatibilized with poly(lactic acid)-grafted maleic anhydride (PLA-g-MA). HNTs and PLA-g-MA were added to the polymer blend at 5 and 10 wt.%, respectively, and everything was processed via melt compounding. A scanning electron microscopy (SEM) analysis shows that HNTs are preferentially localized in PHBHHx nodules rather than in the PLA matrix due to its higher wettability. When HNTs are combined with PLA-g-MA, a finer and a more homogeneous morphology is observed, resulting in a reduction in the size of PHBHHx nodules. The presence of HNTs in the polymer blend improves the impact strength from 12.7 to 20.9 kJ/mm2. Further, with the addition of PLA-g-MA to PLA/PHBHHX/HNT nanocomposites, the tensile strength, elongation at break, and impact strength all improve significantly, rising from roughly 42 MPa, 14.5%, and 20.9 kJ/mm2 to nearly 46 MPa, 18.2%, and 31.2 kJ/mm2, respectively. This is consistent with the data obtained via dynamic mechanical analysis (DMA). The thermal stability of the compatibilized blend reinforced with HNTs is also improved compared to the non-compatibilized one. Overall, this study highlights the effectiveness of combining HNTs and PLA-g-AM for the properties enhancement of PLA/PHBHHx blends.

RESUMEN

Films-based bionanocomposites have gained a great importance in food plastic packaging because they are eco-friendly materials and have the potential to improve food protection, while limiting the accumulation of synthetic plastics on the planet. In this paper, biofilms were prepared using poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) reinforced with Zinc oxide nanoparticles (ZnO-NPs) to develop new bionanocomposite materials intended for food packaging. The samples were fabricated using first solvent casting method followed by melt compounding at various loading rates, i.e., 1.5, 3 and 6 wt%. The obtained results showed that the incorporation of ZnO-NPs to PHBHHx at 3 wt% leads to higher crystallinity, improved mechanical properties and antimicrobial activity, compared with neat polymer and other bionanocomposites. This was attributed to the finer and homogeneous nanofiller dispersion in the polymer matrix evidenced by scanning electron microscopy analysis. Whereas at 6 wt%, the bionanocomposite sample exhibited low mechanical properties due to the formation of ZnO-NPs aggregates. In view of the obtained results, the study highlights the potential of using the PHBHHx/ZnO-NPs bionanocomposite at 3 wt% in food packaging without any prior filler treatment.

Asunto(s)

Nanopartículas , Óxido de Zinc , Embalaje de Alimentos , Hidroxibutiratos , Polímeros

RESUMEN

The effect of hydroxyapatite (HAp) synthesized by the chemical precipitation process on the morphology and properties of composites based on poly(lactic acid) (PLA) was investigated at various filler content ratios, i.e., 5, 10 and 15 wt%. Both neat PLA and PLA-based composites were first prepared using the solvent casting method, followed by melt compounding in an internal mixer, whereas tensile specimens were obtained by thermo-compression. The study revealed that the addition of 5 wt% of HAp into the PLA led to a slight improvement in both the thermal stability and tensile properties of the composite material in comparison with neat PLA and other composite samples. Indeed, the values of the tensile strength and modulus increased from approximately 61 MPa and 2.9 GPa for the neat PLA to almost 64 MPa and 3.057 GPa for the composite sample, respectively. Moreover, the degradation temperature at a 5 wt% mass loss also increased by almost 5 °C compared to other samples, due probably to a finer dispersion of the HAp particles in the PLA, as observed under a scanning electron microscope. Furthermore, the FT-IR spectra displayed some changes in the chemical structure of the PLA/HAp (5 wt%), indicating the occurrence of filler-matrix interactions. At a higher filler content ratio, a decrease in the properties of the PLA/HAp composites was observed, being more pronounced at 15 wt%. The PLA composite containing 5 wt% HAp presents the best compromise among the investigated properties. The study highlighted the possibility of using HAp without any prior surface treatment as a reinforcement in PLA composite materials.