Abstract Peanut crop waste (hulls), which have a chemical composition similar to wood, can be considered as a source of industrial raw material for the production of particleboard, provided that they are of similar quality to wooden panels. The present study aimed to produce and evaluate the physical and mechanical properties of medium density particleboards made of peanut hulls and pine wood particles bonded with urea-formaldehyde adhesive. The panels did not present satisfactory dimensional stability. The mechanical properties were significantly reduced with the addition of peanut hulls. In general, peanut hulls did not represent a good alternative to be used as a source of raw material for the production of particleboard. The inclusion of new parameters in the production process would be essential to improve the technological properties, such as: new particle geometries, use of paraffin, particle treatments and inclusion of denser species in the composition of the panels.

RESUMO O descarte inadequado de polímeros de origem petrolífera contribui para o aumento da poluição ambiental devido ao grande período de tempo que estes materiais levam para degradar. Assim, o desenvolvimento de materiais poliméricos reforçados com resíduos de materiais lignocelulósicos pode proporcionar uma melhor taxa de biodegradação ao polímero, por se tratar de materiais de origem natural, renovável e biodegradável. Neste sentido, o objetivo desta pesquisa foi verificar o potencial de utilização do resíduo de soja como carga em polietileno de baixa densidade (PEBD) através de caracterização físico-mecânica. Foram avaliadas diferentes composições do resíduo de soja em relação à massa total de PEBD 0%, 5%, 10%, 15% e 20%. O resíduo de soja utilizado foi caracterizado quimicamente para determinação do teor de extrativos, lignina, cinzas e hemicelulose. Os pellets formados por extrusão foram prensados a uma temperatura de 160°C sem pressão durante 12 minutos, onde se obteve os corpos de prova para os ensaios físico-mecânicos. Após a produção, os mesmos foram acondicionados em sala de climatização com temperatura de 20±2°C e umidade relativa de 65±3%, sendo posteriormente realizada a determinação da densidade aparente, umidade na base seca, absorção total de água e realizados de flexão e tração. Com base nos resultados, conclui-se que os valores encontrados para os constituintes químicos do resíduo de soja mostram satisfatórios, uma vez que, a substituição parcial do PEBD puro pelo não afetou as propriedades de densidade e resistência à tração do material. O aumento do teor deste resíduo, também contribui para um maior alongamento do polímero. Assim, conclui-se que é possível transformar este polímero de origem petrolífera em um material mais sustentável, tornando algumas propriedades até mais atrativas do que aquelas encontradas no PEBD puro.

ABSTRACT The improper disposal of polymers of petroleum origin contributes to the increase of environmental pollution due to the long period of time that these materials take to degrade. Thus, the development of polymeric materials reinforced with residues of lignocellulosic materials can provide a better rate of biodegradation to the polymer, as they are materials of natural, renewable and biodegradable origin. In this sense, the objective of this research was to verify the potential of using soybean residue as a filler in low density polyethylene (LDPE) through physical-mechanical characterization. Different soy residue compositions were evaluated in relation to the total mass of LDPE 0%, 5%, 10%, 15% and 20%. The soybean residue used was chemically characterized to determine the content of extractives, lignin, ash and hemicellulose. The pellets formed by extrusion were pressed at a temperature of 160 ° C without pressure for 12 minutes, where the specimens were obtained for the physical-mechanical tests. After production, they were stored in an air conditioning room with a temperature of 20 ± 2 ° C and a relative humidity of 65 ± 3%, with the determination of apparent density, moisture on the dry basis, total water absorption and subsequently carried out. flexion and traction. Based on the results, it is concluded that the values found for the chemical constituents of the soy residue are satisfactory, since the partial substitution of pure LDPE by the material did not affect the density and tensile strength properties of the material. The increase in the content of this residue also contributes to a greater elongation of the polymer. Thus, it is concluded that it is possible to transform this petroleum-based polymer into a more sustainable material, making some properties even more attractive than those found in pure LDPE.. Keywords: Polymeric materials. Lignocellulosic waste. Sustainability.

ABSTRACT Efforts have been done in order to decrease the human dependence on petroleum materials. This idea can be applied for wood adhesives and wood products. This study proposes to evaluate laminated veneer lumber (LVL) panels of Hevea brasiliensis produced with castor oil-based polyurethane and resorcinol formaldehyde in different grammages. Six rubber tree (12 years old) with diameters at breast height (DBH) > 25 cm were harvested to generate veneers (500 x 500 x 2 mm; length, width, and thickness, respectively) for the panels production. The veneers were pre classified by a non-destructive impulse excitation method (Sonelastic system). Seven veneers were arranged in the same grain direction to produce each LVL. The following grammages were used for each adhesive type: 240, 280 and 320 g.m-². The volumetric swelling of the panels, glue line strength under dry, wet and post-boiling conditions, and stiffness and strength in static bending tests in flatwise and edgewise positions were evaluated. The glue line was evaluated by optical microscopy. The panels with grammages of 240 g.m-² had the highest volumetric swelling for both adhesives. As the grammage increased from 240 to 280 g.m-², the panel volumetric swelling decreased 32.53% for the resorcinol formaldehyde adhesive and 21.42% for the castor oil-based polyurethane adhesive. The panels glued with the vegetal polyurethane adhesive presented the best results for shear strength in the glue line. No significant statistical differences were found between the compositions for static bending. The results indicate that rubber wood glued with vegetal polyurethane has the potential to be used for production of LVL panels and consequently replace the petroleum based adhesives.

ABSTRACT The aim of this study was to evaluate the properties of Hevea brasiliensis wood wastes for production structural pieces of glued laminated (glulam) timber. Three trees with age close to 25 years and diameter at breast height (DBH) higher than 500 mm were obtained. The basic density of the wood were quantified, as well as the stiffness and the strength in static bending, shear strength and parallel compression to grain and hygroscopic equilibrium moisture. The beams of glulam were evaluated according to the modulus of elasticity (MOE), modulus of rupture (MOR) and delamination. Due to the bending properties MOR (75.14 MPa) and MOE (8166.79 MPa), as well as the shear strength (12.29 MPa) obtained, was concluded by the suitability of the rubber wood for the production of glulam beams. The composite beams presented values of MOR (75.14 MPa) and MOE (8166.79 MPa) compatible with species traditionally used in the production of glulam beams. The adhesive bond quality was verified by the delamination test, presenting delamination of 4.95 %, indicating its use for internal and external environments.

ABSTRACT The aim of this work was to evaluate the physical and mechanical properties of particleboards using particles from wood shaving at three urea-formaldehyde adhesive contents: 6, 9 and 12% (dry mass basis). The particleboards were produced with nominal density of 0.70 g.cm-3, pressing cycle with temperature of 160 °C, pressure of 3.92 MPa and time of 8 minutes. The properties of water absorption (WA), thickness swelling (TS), both after 2 and 24 hours, apparent density, compression ratio, perpendicular traction, modulus of elasticity (MOE) and modulus of rupture (MOR) in static bending, Janka hardness and screw withdrawal resistance were evaluated. The results of the tests indicated that with the increase of the adhesive content from 6 to 12%, there was no significant statistical difference for the average values of apparent density and compression ratio, being 0.621 g.cm-3 and 1.234, respectively, and the WA and the TS are decreased after 2 and 24 hours. There was a gain of 93% for the MOR property and 64% for the MOE property with the increase of the adhesive content. For perpendicular traction, the highest mean value was 0.67 MPa, referring to the panels with 12% of adhesive. For Janka hardness, the treatments with contents of 9 and 12% of adhesive presented the highest average values being of 21.60 and 25.26 MPa, respectively. In general, the use of wood shavings is feasible for the production of particleboards with a 12% adhesive content.

Entrar em contato com os ciganos e seu mundo de significações e práticas que podemos chamar de cultura cigana ou 'ciganidade', mesmo correndo o risco das generalizações, é estar em contato com um tema que insiste em escapar entre nossos dedos. Deparamo-nos com um povo que ao longo da história acabou se adaptando a cada novo encontro e a cada nova região, buscando sobreviver em um mundo que busca e valoriza os seus contrários. Mesmo assim, esse povo manteve muitas de suas tradições intactas durante séculos de nomadismo. Para os ciganos nômades, a barraca é o seu lugar. Durante séculos as adjetivações negativas em relação aos ciganos aparecem em leis, decretos, matérias jornalísticas, processos criminais e também nas artes. Esses processos de exclusão fizeram e fazem parte da dinâmica dos Estados que veem os grupos ciganos como perigosos e desnecessários.

Contacting Romani and their world of symbols and practices - which may be called Romani culture or 'gypsism', even at the risk of generalization - is being in touch with a theme which insists on slipping through our fingers. We are faced with a people which, throughout history, ended up getting adapted after every new encounter and region, in order to be able to survive in a world that seeks their opposites, and, nevertheless, kept intact many of their traditions through centuries of nomadism. For the nomadic Romani people, the tent is their home. Along centuries, derogatory terming towards gypsy appears in laws, decrees, newspaper articles, criminal case reports as well as in the arts. These exclusion processes were and are part of the States' dynamics which regards Roma groups as dangerous and unnecessary.