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The iron mine tailings accumulation in dams is an environmental and economic problem. The composite based on high-density polyethylene/iron mine tailing production for the application of wood plastic and some items of domestic plastic industry can be a good alternative to reduce the rejects in the environment. This work presents the influence of the processing methodology in the mechanical, thermal and morphological properties of composites based on the high-density polyethylene/iron mine tailing. Four methodology processing by continuous and/or batch mixing were available. The iron mine tailing particles in the polymer matrix promoted an increase in mechanical strength and thermal stability. Besides, the particles acted as flame retardant. The iron mine tailing materials produced using batch mixing showed more significant modifications in the properties due to the better dispersion of the filler as shown by scanning electron microscopy.

The PHB (poly (3-hydroxybutyrate)) film and nanocomposite act as catalysts in the oxidation of organic compounds, such as methylene blue dye (MB) using UV radiation. The results indicate that the materials produce in situ hydroxyl radicals, which are responsible for the deep oxidation of MB. The results showed for the first time that only the PHB polymer presents good catalytic activity (∼80%), indicating the possibility of avoiding the use of semiconducting metals in the processes. The main effect is the cleavage of the polymer chains which modifies the PHB structure. This effect also promotes the mineralization of the PHB polymer during the process. Thus, the polymer degrades organic molecules present in water and is also transformed without generating pollutant molecules, as shown by the ESI-MS analyzes. This new catalyst concept allows its use for up to 7 cycles efficiently without semiconductor metals.

Etoposide-loaded poly(lactic-co-glycolic acid) implants were developed for intravitreal application. Implants were prepared by a solvent-casting method and characterized in terms of content uniformity, morphology, drug-polymer interaction, stability, and sterility. In vitro drug release was investigated and the implant degradation was monitored by the percent of mass loss. Implants were inserted into the vitreous cavity of rabbits' eye and the in vivo etoposide release profile was determined. Clinical examination and the Hen Egg Test-Chorioallantoic Membrane (HET-CAM) method were performed to evaluate the implant tolerance. The original chemical structure of the etoposide was preserved after incorporation in the polymeric matrix, which the drug was dispersed uniformly. In vitro, implants promoted sustained release of the drug and approximately 57% of the etoposide was released in 50 days. In vivo, devices released approximately 63% of the loaded drug in 42 days. Ophthalmic examination and HET-CAM assay revealed no evidence of toxic effects of implants. These results tend to show that etoposide-loaded implants could be potentially useful as an intraocular etoposide delivery system in the future.

Nowadays, to develop products with lower impact without harming the environment. The aim of this work was to develop a polymer composite based in thermoplastic starch (TPS), maleate polyethylene (PE- g -MA) and curaua fiber in the proportion of 10%, 20% and 30 wt%. The resulting material was characterized by infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), tensile test, scanning electronic microscopy (SEM) and optical microscopy. The developed composite was applied on ceramic blocks and subjected to natural sunlight; its thermal behavior was monitored using infrared thermography. Thermography was effective for identifying temperature differences in samples of polymer composites with different percentages of fiber and allowed to monitor the thermal behavior. The results show that the manufactured composites have potential for use as thermal insulated building element.

In this work, it has been reported the preparation of catalytic systems based on chemically modified niobium oxides and different polymer matrices, polypropylene (PP), poly(3-hydroxibutyrate) (PHB) and polyurethane (WPU). The efficiency of systems as photocatalytis was investigated. Materials prepared from various polymer matrices showed distinct photocatalytic activities. The systems based on PHB matrix and niobium oxihydroxide presenting the best performance among the studies systems, ~ 90% dye removal at 60 min. The results of systems characterization by Scanning Electron Microscopy (SEM), Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC) analysis technical have showed that nanoparticles size, their dispersion in the polymeric matrix and interaction polymer-inorganic particles are responsible by changing photocatalysis process. However, for the PHB, structure parameters of matrix are important. The synchrotron radiation was used to investigate the macromolecular structure of the pure polymers and after the incorporation of niobium nanoparticles.

Collagen is an important biomaterial because it has many applications in the biomedical sector. However, the high hydrophilicity of collagen (COL) leads to easy swelling. Thus, controlling this property is highly desirable. In this work, cellulose nanocrystals (CNCs) dispersed in glycerol (GLI) were incorporated in the matrix collagen to tailor the hydrophilicity and mechanical properties. Study of the hydrophilicity of the bio-based nanocomposite was evaluated by contact angle measurement and thermogravimetric analysis. Mechanical analyses showed that CNCs are excellent reinforcing fillers to the collagen matrix. Synchrotron small-angle X-ray scattering was employed to investigate the nanostructures of COL/GLI/CNC nanocomposites and CNC water dispersion. CNC in concentrations up to 1 wt% presents an intermediate shape between a rod and a plane with a 9.34-nm radius of gyration (R g). Bio-based nanocomposites present two different structural levels with two types of particles with very different R gs. At the intermediate power-law regime, a large-scale mass fractal aggregate is observed. In the high-power-law regime, it is observed scattering from primary particles smaller than 1 nm. As the CNC concentration increases, the original particle distorts from a rod to a plate. The cytotoxicity assay indicates that the collagen and nanocomposites did not affect the cell viability of rat calvarial cells in vitro.

In this work, nanostructured niobium oxyhydroxide was dispersed over poly (3-hydroxybutyrate) (PHB), which is a biopolymer, for application as a photocatalyst using visible and UV light. PHB films with different amounts of niobium oxyhydroxide were characterized by diffuse UV–vis reflectance spectroscopy, FTIR-ATR and SEM. The characterizations showed particles of the niobium compound well-dispersed on the polymeric matrix, thus modifying the bandgap value, which improved the photocatalysis process. The material showed excellent catalytic activity (approximately 100% degradation) for the oxidation of methylene blue dye considering the reaction in a continuous flow bath. Moreover, the polymer films were easily removed from the solution after the reaction and reused several times while retaining their high activity. ESI–MS studies showed that the dye removal occurs by the formation of reaction intermediates due to the successive hydroxylation of the dye structure, confirming that the reaction took place improved by photocatalytic conditions.

The glaucoma is an ocular pathology characterized by the increase of intraocular pressure and possibility of retinal degeneration. The treatment is based on the administration of eye drops. However, they do not induce the permanence of drug in the eye, compromising its bioavailability. In this study, inserts based on chitosan and brimonidine tartrate were developed to treat the glaucoma by improving the drug bioavailability. Inserts were characterized using different analytical techniques FTIR, SEM, DSC and WAXS. The in vitro release profile of drug from inserts was evaluated. The in vitro biocompatibility against ARPE-19 and MIO-M1 cells was investigated. The in vivo biocompatibility using the chorioallantoic membrane was also demonstrated. Analytical techniques demonstrated that the amorphous drug was physically dispersed into the polymeric chains without chemical interactions. However, a portion of drug crystals was on the surface of systems. Inserts provided the controlled release of drug for 30 days without a burst effect. Inserts did not induce a deleterious effect to ocular cells, indicating their biocompatibility. They were also well tolerated in vivo , suggesting the absence of toxicity. These inserts could be potential delivery systems to reduce the intraocular pressure and to induce neuroprotective effects in glaucomatous patients.

In this work, Nb2O5 and red mud (RM) were separately added to Portland cement for application as photocatalysts using visible (vis) and ultraviolet (UV) light. The resultant materials, i.e., mortar/RM and mortar/Nb2O5, were characterized by UV–vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy-attenuated total reflectance, thermogravimetry, photocatalytic tests, and scanning electron microscopy. The characterization results showed that the Nb2O5 and RM particles were micrometric and that their mixtures with mortar exhibited homogeneous and uniform morphologies. The addition of the particles modified the bandgap value of mortar and improved its photocatalytic performance. The materials exhibited catalytic activity for the oxidation of methylene blue dye using UV radiation. In addition, the mortar/RM showed the best performance in the removal of methylene blue dye while the photocatalytic activity of Nb2O5 was compromised when it was mixed with mortar. It is noteworthy that cementitious materials with additives have the potential for use in self-cleaning surfaces.

The present study concerns an innovative technology for the extraction of chromium, which is present in leather industry wastes, to facilitate the application of chromium-free protein (collagen) as a slow-release drug carrier in skin treatment when there are burns, ulcers and infected wounds. The study focuses on the excavation of industrial landfills, which are currently saturated, to recycle residual wet blue leather to obtain purified collagen films. These films, as biocompatible materials, offer great potential as drug carriers. We test here the material's ability to retain/release silver sulfadiazine and its potential to impede the proliferation of various bacteria. The very promising results demonstrate that the material possesses a high capacity for delivery of the drug and great efficiency in inhibiting bacteria proliferation. The obtained results indicate that the treatment proposed for chromium removal is capable of generating a material rich in amino acids that can be transformed into films with no cellular incompatibility, therefore creating a new field of study from a material that presents a serious environmental liability.

In this study a novel approach for improving the photo-stabilization of polymers by incorporation of nanoparticles of a new niobium compound is reported. For the first time, this approach uses the electronic properties of niobium oxyhydroxide to absorb UV light efficiently to avoid the decomposition of the polymers. The innovative results of this work consist of preparing nanoparticles of niobium oxyhydroxide and its modification by treatment with hydrogen peroxide to alter their ability to absorb radiation and act as a photo-stabilizer for preventing polypropylene degradation. Synchrotron radiation was employed: (i) to explore the niobium nanoparticle form and (ii) to investigate the macromolecular structure of neat PP and PP/Nb compounds before and after degradation. The results from this research study using FTIR-ATR, DSC and microscopies, as TEM, SEM and OM, indicate that the incorporation of niobium oxyhydroxide nanoparticles into the PP matrix provides stability against the action of ultraviolet radiation.

In this work, it is proposed a new strategy to improve the dispersion of inorganic fillers in polymeric matrices by producing surface carbon nanostructures. Clay/carbon nanofibers particles were prepared and used as fillers to improve the mechanical and thermal properties of ultra-high molecular weight polyethylene (UHMWPE). Thermogravimetry (TG), differential scanning calorimetry (DSC), elemental analyses, Raman, X-ray diffraction (XRD) and scanning electron microscopy (SEM) showed that chemical vapor deposition (CVD) with ethanol at different temperatures, i.e. 700, 800 and 900 °C with and without Fe catalyst, can be used to produce carbon (0.5-3.6 wt.%), mainly as nanofibers, on the clay surface. The use of these clay/carbon particles as fillers in UHMWPE at 1 and 3 wt.% produced an increase in the yield stress from 16 to ca. 20 MPa and Young modulus from 314 MPa for pure UHMWPE to values near 395-408 MPa. Moreover, the presence of the carbon/clay composites led to a strong improvement of the thermal properties of the UHMWPE increasing the decomposition Tonset (degradation start temperature) from 445 up to 472 °C. It was also observed by the crystallization enthalpies that the UHMWPE increased the crystallinity from 55 to 80-85% in the presence of the carbon composites. These results are discussed in terms of the strong interactions of the hydrophobic carbon nanostructures on the clay surface with the polymer hydrophobic chains.

Collagen (Col) is extensively used in various applications, including pharmaceutical, agricultural, and food applications. The materials based in Col may exhibit properties of biomedical interest because of their low toxicity, high structural capacity support, controlled biodegradability, and biocompatibility. However, Col has poor thermal and mechanical properties. The addition of plasticizers (Plas's) and fillers is an established strategy for enhancing the properties of the resulting nanocomposites. In this study, nanocomposites based on Col and cellulose nanocrystals were developed in two different ways and with three different Plas's. These materials were subjected to structural, thermal, mechanical, and morphological analysis. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44954.

Materials that can switch from stiff to soft or from brittle to tough by slightly changing the temperature, pH, electric, or magnetic fields of their environments, can have a pronounced impact on many applications, including sensors, biomedical materials for less invasive surgeries, and packaging materials. In this work, temperature-sensitive poly(N-isopropyl acrylamide) grafts and low molar mass polyethylene glycol were incorporated in the interfacial region between clay nanoparticles and a bacteria-derived polyhydroxybutyrate matrix to determine if the application of an external stimulus, such as small changes in temperature, could increase the toughness of the nanocomposites. The obtained materials were characterized by using thermal analysis, infrared spectroscopy, dynamic light scattering and dynamic mechanical tests. Mechanical properties were also evaluated at different temperatures and showed that small changes in temperature, such as from 25°C to 40°C, led to a pronounced increase in strain at break of the nanocomposites containing the modified interface. The external stimulus associated with the increase in temperature from 25°C to 40°C can reduce the interfacial interactions between clay and polymer matrix and create a highly plasticized polymer layer between the components of the nanocomposite, which favored the sliding of the interface and ultimately led to high values of elongation. POLYM. COMPOS., 2014. © 2014 Society of Plastics Engineers

Porous synthetic substrates are developed through tissue engineering technologies to grow new tissue, restoring the function of tissue or an organ. For bone regeneration, these scaffolds must support the dynamic load exerted on this tissue, achieved primarily by increasing their compression strength, as established in the literature. The aim of this paper was to incorporate an inorganic composite bioactive glass (60%SiO2 - 36%CaO - 4%P2O5) as a reinforcing agent in mechanical 3D scaffolds that must remain porous. Two strategies were adopted: a co-precipitation method to obtain a nanoparticulate dispersion of bioactive glass (BGNP) and a sol-gel method to combine a bioactive glass solution (BG) with a previously prepared chitosan polymer solution. Moreover, a lyophilization process was also used, generating highly porous scaffolds. Various aspects of the scaffold were evaluated, including the morphology, orientation and size of the pores, and mechanical strength, as obtained using the two synthetic methods. The data for compressive strength revealed increased strength after the incorporation of bioactive glass, which was more pronounced when utilizing the nanoscale bioactive glass.

In this work, nanocomposites were obtained by the dispersion of niobium oxyhydroxide into a poly(3-hydroxybutyrate) (PHB) matrix by different preparative methods. These methods led to changes in the polymer morphology and in their photocatalytic properties. Thermal and structural properties of the nanocomposites were investigated using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR)–attenuated total reflection (ATR). Scanning electron microscopy images were analyzed in order to observe the different morphologies of nanocomposites as well as the distribution of niobium nanoparticles in the PHB matrix. The chemical interactions between the polymer and niobium nanoparticles were observed in the FTIR–ATR and thermal analyses. The results of TGA and DSC indicated an improvement in the thermal stability of the polymer and the action of inorganic nanoparticles as nucleating agents in the process of heterogeneous nucleation of PHB. The composites exhibited good catalytic activity for the removal of methylene blue dye from an aqueous medium (∼90%) during a photocatalytic process. The different morphologies of PHB/niobium oxyhydroxide composites directly influenced the catalytic activity of the material due to the difference in the dispersion of nanoparticles. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 45836.