Resumo em Inglês:

Abstract One of the most widespread applications of poly(lactic acid) (PLA) is as a raw material in the form of filaments for 3D printing. To improve final disposal alternatives and minimize their effects on the environment, the aim of this study is to determine the biodegradability of 3D-printed PLA waste composted in a landfill with leachate soil and garden soil for 90 days and 180 days. The soil characteristics and material properties were evaluated by laboratory analyses. Changes in soil chemical composition and the loss of microorganisms were recorded. The thermal and mechanical properties of PLA did not change significantly, but fungal colonies, encrustation, and changes in the original colour were found, indicating the onset of surface biodegradation of the samples. Controlled conditions or longer periods would be needed to maintain an ecosystem favourable to biodegradation; otherwise, PLA could accumulate in the environment, causing future pollution problems.

Resumo em Inglês:

Abstract Scaffolds with osteoconductivity, biocompatibility and good mechanical properties are promising for local drug release of sodium alendronate (ALN), a first-choice drug for treatment of bone tissue diseases, with low bioavailability. The viability to manufacture poly (L-lactic acid) (PLLA)/poly (methyl methacrylate) (PMMA) filaments containing ALN in different proportions, through extrusion, followed by scaffolds using 3D printing by fusion deposition modelling (FDM) and to investigate the influence of processes in mixtures drove this study. Differential scanning calorimetry (DSC), spectroscopy in the infrared region with Fourier transform (FTIR/ATR), and X-ray diffractometry (XRD) analysis indicated that PMMA decelerates crystallinity and confers malleability to PLLA/ALN mixture, besides its good processability and miscibility with PLLA and no relevant changes in physicochemical properties of components. Field emission scanning electron microscopy (SEM/FEG) showed good interfacial compatibility between PLLA/PMMA and homogeneously dispersed drug crystals in matrix. PLLA-PMMA-ALN scaffolds were manufactured by accurate with interesting properties for bone tissue engineering.

Resumo em Inglês:

Abstract Waterborne polyurethane (WPU) coatings used for moisture protection of surfaces have been used broadly. They have been considered environmentally friendly because their synthesis releases less or no volatile organic compounds (VOCs) to the atmosphere. With the Covid-19 pandemic concerns, cleaning protocols of these surfaces have been applied and scientific knowledge about the effects of these liquids on WPU surfaces is necessary. In this work, diffusion experiments were performed using four liquids, in pure WPU and WPU filled with graphene oxide (GO). Detergent had the most severe effect on polyurethane films, causing severe cracks and weight loss. Diffusion parameters of HCl 5% and HCl 10% were greater in WPU/GO nanocomposites than in pure WPU. Mechanical tests under chemical aging showed that alcohol reduced most the tensile strength and Young modulus. Overall, GO protected the films for all liquid exposures, increasing their tensile strength and Young modulus.