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Biodegradable nanocomposites were prepared by adding ZnO nanoparticles to bacterial polyester poly­(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) via solution casting technique. The morphology, thermal, mechanical, antibacterial, barrier, and migration properties of the nanocomposites were analyzed. The nanoparticles were uniformly dispersed within PHBV without the aid of coupling agents, and acted effectively as nucleating agents, raising the crystallization temperature and the level of crystallinity of the matrix while decreasing its crystallite size. A gradual rise in thermal stability was found with increasing ZnO loading, since the nanofillers hinder the diffusion of volatiles generated during the decomposition process. The nanocomposites displayed superior stiffness, strength, toughness, and glass transition temperature, whereas they displayed reduced water uptake and oxygen and water vapor permeability compared to the neat biopolymer, related to the strong matrix–nanofiller interfacial adhesion attained via hydrogen bonding interactions. At an optimal concentration of 4.0 wt % ZnO, the tensile strength and Young’s and storage moduli showed a maximum that coincided with the highest crystallinity and the best barrier properties. PHBV/ZnO films showed antibacterial activity against human pathogen bacteria, and the effect on Escherichia coli was stronger than on Staphylococcus aureus. The overall migration levels of the nanocomposites in both nonpolar and polar simulants dropped upon increasing nanoparticle content, and were well below the limits required by the current normative for food packaging materials. These sustainable nanomaterials with antimicrobial function are very promising to be used as containers for beverage and food products as well as for disposable applications like cutlery or overwrap films.

New poly(ether ether ketone) (PEEK) based composites have been fabricated by the incorporation of single-walled carbon nanotubes (SWCNTs) using melt processing. Their structure, morphology, thermal and mechanical properties have been investigated. Scanning electron microscopy observations demonstrated a more uniform distribution of the CNTs for samples prepared following a processing route based on polymer ball milling and CNT dispersion in ethanol media. Thermogravimetric analysis indicated a remarkable improvement in the thermal stability of the matrix by the incorporation of SWCNTs. Differential scanning calorimetry showed a decrease in the crystallization temperature with increasing SWCNT content, whilst no significant changes were observed in the melting of the composites. The

Poly(propylene fumarate) (PPF)-based nanocomposites incorporating different amounts of polyethylene glycol-functionalized graphene oxide (PEG-GO) have been prepared via sonication and thermal curing, and their surface morphology, structure, thermal stability, hydrophilicity, water absorption, biodegradation, cytotoxicity, mechanical, viscoelastic and antibacterial properties have been investigated. SEM and TEM images corroborated that the noncovalent functionalization with PEG caused the exfoliation of GO into thinner flakes. IR spectra suggested the presence of strong hydrogen-bonding interactions between the nanocomposite components. A gradual rise in the level of hydrophilicity, water uptake, biodegradation rate, surface roughness, protein absorption capability and thermal stability was found upon increasing GO concentration in the composites. Tensile tests revealed improved stiffness, strength and toughness for the composites compared to unfilled PPF, ascribed to a homogeneous GO dispersion within the matrix along with a strong PPF/PEG-GO interfacial adhesion via polar and hydrogen bonding interactions. Further, the nanocomposites retained enough stiffness and strength under a biological state to provide effective support for bone tissue formation. The antibacterial activity was investigated against Gram-positive Staphylococcus aureus and Staphylococcus epidermidis as well as Gram-negative Pseudomonas aeruginosa and Escherichia coli microorganisms, and it rose sharply upon increasing GO concentration; systematically, the biocide effect was stronger versus Gram-positive bacteria. Cell viability data demonstrated that PPF/PEG-GO composites do not induce toxicity over human dermal fibroblasts. These novel materials show great potential to be applied in the bone tissue engineering field.