Natural lignocellulosic fibers (NLFs) have in recent decades appeared as sustainable reinforcement alternatives to replace synthetic fibers in polymer composite material applications. In this work, for the first time, the periquiteira (Cochlospermum orinocense), a lesser known NLF from the Amazon region, was analyzed for its density and, by X-ray diffraction (XRD), to calculate the crystallinity index as well as the microfibrillar angle (MFA), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), scanning electron analysis (SEM) and tensile strength. The apparent density found for the periquiteira fiber was 0.43 g/cm³, one of the NLF’s lowest. XRD analysis indicated a crystallinity index of 70.49% and MFA of 7.32°. The TGA disclosed thermal stability up to 250 °C. The FTIR analysis indicated the presence of functional groups characteristic of NLFs. The SEM morphological analysis revealed that the periquiteira fiber presents fine bundles of fibrils and a rough surface throughout its entire length. The average strength value of the periquiteira fiber was found as 178 MPa. These preliminary results indicate that the periquiteira fiber has the potential to be used as a reinforcing agent in polymeric matrices and can generate a lightweight composite with excellent mechanical properties that can be used in various industrial sectors.

The search for new natural, sustainable, economical and biodegradable reinforcements for composite materials has increased in recent years, highlighting the importance of fibers from the natural environment. This work evaluates the use of tururi fibrous fabric as a reinforcement in a polymer matrix, using Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetry and scanning electron microscopy. The mechanical and fractographic performance of composites reinforced with 2.5, 5.0 and 7.5% mass fraction of tururi in a polyester matrix is also investigated. The FTIR and XRD results identified groups characteristic of natural fibers and the presence of elemental constituents such as cellulose, hemicellulose and lignin. Thermogravimetry indicated good thermal stability near 246 °C. The morphology of the fibrous fabric is irregular and formed by tangles of threads. The mechanical behavior of the composites in bending revealed a variation in stress with the increase in the percentage of fabric in the matrix, explained by defects and failures due to low interfacial adhesion between the phases. Impact tests indicated that increasing the percentage of fabric in the matrix improves impact energy absorption, reflecting better adhesion and load distribution. Thus, the development of this natural composite is promising for applications in green and sustainable products.

O minério de ferro é essencial para a obtenção dos aços, os quais são materiais amplamente utilizados em nossa sociedade. No Brasil as principais reservas mineralógicas associadas aos depósitos de ferro estão localizadas na província mineral de Carajás, situada no estado do Pará. Este estudo apresenta para o minério obtido na província de Carajás, uma revisão de suas características gerais como: ocorrência, alteração, composição, propriedades físicas e aplicações. Por meio de dados da literatura foi observado que a hematita, magnetita e goethita estão presentes no minério de ferro encontrado na província de Carajás. Diante do exposto, esta investigação exibe informações úteis com potencial benefício para o setor mineral e industrial.

Ceram. Ind., vol.29, e1129, 2024