Silvia Luciana Fávaro

Preparation and characterization of Zein and Zein-Chitosan microspheres with great prospective of application in controlled drug release

Biomaterials applied as carriers for controlled drug delivery offer many advantages over the conventional systems. Among them, the increase of treatment effectiveness and also a significant reduction of toxicity, due to their biodegradability property, are some special features. In this work, microspheres based on the protein Zein (ZN) and ZN associated to the natural polymer Chitosan (CHI) were prepared and characterized. The microspheres of ZN and ZN/CHI were characterized by FT-IR spectroscopy and thermal analysis, and the morphology was analyzed by SEM images. The results confirmed the incorporation of CHI within the ZN-based microspheres. The morphological analysis showed that the CHI added increased the microspheres porosity when compared to the ZN microspheres. The chemical and physical characterization and the morphological analysis allow inferring that ZN/CHI microspheres are good candidates to act as a carrier for controlled drug release.

AuNp@MOF composite as electrochemical material for determination of bisphenol A and its oxidation behavior study

A composite material based on a metal organic framework (MOF), nanowhisker of Al2O3 silanized with (3-aminopropyl)triethoxysilane (APTES) and gold nanoparticles (AuNp) was synthesized and characterized. This material was used to prepare an electrode based in carbon paste (CPE) and applied as a sensor for the determination of bisphenol A (BPA). The electrochemical characterizations and behaviour of the electrode containing the AuNp@MOF composite exhibited a 2.3 higher electroactive surface area, when compared with just CPE. Using differential pulse voltammetry (DPV), it can be noted that the presence of AuNp plays an important role in enhancing the analyte signal detection of BPA 2.5-fold. A linear increase in emphasizing the response as a function of analyte concentration is demonstrated. In this account, we believe that this composite may be applied in analyticals methods for the determination of BPA and others endocrine disruptors.

Physico-chemical properties of meso-tetrakis(p-methoxyphenyl)porphyrin (TMPP) incorporated into pluronicTM p-123 and f-127 polymeric micelles

The physicochemical properties (solubilization, structural organization and stability) of meso-tetrakis(p-methoxyphenyl)porphyrin (TMPP), a promising photosensitizer for photodynamic therapy, solubilized in polymeric micelles of tri-block copolymers PluronicTM P-123 and F-127, were studied. The formulations obtained by the solid dispersion method led to monomerization of TMPP in these copolymers. Solubility studies showed that P-123 solubilizes double the photosensitizer than F-127. The self-aggregation phenomenon was affected by the [TMPP]/[poloxamer] ratio and medium temperature. The decrease in the temperature of these systems promoted the formation of different kinds of TMPP aggregates intrinsically connected with the structural changes occurring in the micelles.

Synthesis of zeolite from multilayer food packing and sugar cane bagasse ash for CO2 adsorption

The X/A zeolite crystal mixtures were synthesized using sugar cane bagasse ash (SCBA) as a silicon source and multilayer food packing (MFP) as an aluminum source under hydrothermal conditions at 80 °C for 79–296 hours. The silicon was extracted by alkaline fusion for 40 min at 550 °C with an alkali–SCBA weight ratio of 1:1. The aluminum solution was obtained from MFP using NaOH 1 M (3:1 water–acetone) solution. The synthesized zeolites were analyzed by XRD, FTIR, SEM, and BET. In the XRD results, most of the signals were indexed to zeolite X, and some signals were indexed to zeolite A. The vibration bands in the region 1200–400 cm−1 suggested the presence of the double-six-ring (D6R) zeolite X structure. The crystal morphology is characteristic of the zeolite X, and the specific area found by the BET method was 810.47 m2 g−1. The zeolite with the higher specific area was applied in the CO2 adsorption process until it reached 25 bar by the gravimetric method. The experimentally adsorbed amounts were adjusted with the Langmuir, Freundlich, and Toth models.

Hardness and degree of conversion of dental restorative composites based on an organic-inorganic hybrid

This paper presents a factorial design (mixture design) used to analyze the hardness and degree of monomer conversion into composites containing conventional monomers and an organic-inorganic hybrid polymer-based methacryloyloxypropyl trimethoxysilane (MEMO). For this purpose, resins (composites with SiO2) were formulated with the hybrid polymer (polycondensed, pMEMO), and two conventional monomers used in dentistry, bisphenol-A dimethacrylate (Bis-GMA) and triethyleneglycol dimethacrylate (TEGDMA). The resins were characterized through the degree of monomer conversion and Vickers hardness, and the pMEMO by means of FTIR and 1H NMR. The results showed an increase in hardness for resins containing the hybrid material relative to the resins containing only conventional monomers. The mathematical model adjusted to the experimental data yielded an optimized formulation, which presented a higher hardness value (48.88 HV).

Synthesis of α-aminophosphonates using a mesoporous silica catalyst produced from sugarcane bagasse ash

A new green synthesis route is proposed for obtaining a mesoporous material using sugarcane bagasse ash (SCBA) as the silica source. The material obtained was denoted by SBA-16 and its mesostructure was characterized by low-angle X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption techniques. Sulfonic acid groups were introduced to the as-synthesized material, resulting in an acid catalyst denoted by SBA-16/SO3H. The catalytic activities of SBA-16 and SBA-16/SO3H were investigated in Kabachnik–Fields reactions, where α-aminophosphonate compounds were produced. The results show that both products can be considered as promising catalysts, where SBA-16/SO3H showed a slightly better performance than SBA-16.

Preparation and characterization of composites from plastic waste and sugar cane fiber

1Departamento de Física, Universidade Estadual do Centro-Oeste – UNICENTRO, Guarapuava, PR, Brazil 2Departamento de Física, Universidade Estadual de Londrina – UEL, Londrina, PR, Brazil 3Departamento de Química, Universidade Estadual do Centro-Oeste – UNICENTRO, Guarapuava, PR, Brazil 4Departamento de Química, Universidade Estadual de Maringá – UEM, Maringá, PR, Brazil 5Departamento de Engenharia Mecânica, Universidade Estadual de Maringá – UEM, Maringá, PR, Brazil

Mechanical recycling of tags and labels residues using sugarcane bagasse ash

In this study, an alternative method for recycling residues of labels and stickers (parings) containing biaxically oriented polypropylene (BOPP) and polyurethane-based glue was discussed. The recycling of this type of material is complicated, once the separation and the milling processes are difficult to be accomplished, due to the presence of a large amount of glue. In this study, sugarcane bagasse ash was used to enable the milling process of stickers residues. Composites were prepared with post-consumer polypropylene extrusion with different polypropylene/parings ash ratio. These materials were analyzed by tensile, three point flexural, hardness, density, water absorption, Izod impact tests, thermogravimetric analysis, environmental exposure and scanning electron microscopy. Addition of sticker residues/ash to the polypropylene matrix makes the material more rigid and does not affect significantly thermal and degradation properties. Thus, the recycling process proposed in this paper is environmentally and economically viable.

Silanized silica nanoparticles as compatibilizer of sisal fibers/polyethylene composites

Abstract In this study, the influence of silanized silica nanoparticles on the compatibility of composites prepared with sisal fibers and high density polyethylene is discussed. The sisal fibers were chemically treated and covered with silica nanoparticles by mechanical milling. The composites were prepared by extrusion of HDPE and different amount of fibers. The morphology and thermal properties of the sisal fibers and composites, the influence of sisal fibers and silica nanoparticles on crystallinity of HDPE, the mechanical behavior and water uptake of composites were evaluated by different techniques. It was observed that thermal properties of HDPE on composites were not changed by the presence of sisal fibers and silica nanoparticles. The different chemical treatments in sisal fibers and the presence of silica nanoparticles resulted in improved mechanical properties and were preponderant to the water uptake decrease in the composites, comparing with HDPE. Keywords: composites, compatibilization, silanized silica nanoparticle, sisal fibers, mechanical properties.