Antônia Amanda da Silva César

Efeito da incorporação de casca de café nas propriedades físico-mecânicas de painéis aglomerados de Eucalyptus urophylla S.T. Blake

The objective of this study was to evaluate the influence of the incorporation of Coffee husks in the production of particleboard with Eucalyptus urophylla S.T. Blake. The panels were produced incorporating 25%, 50%, and 75% of Coffee husks at three levels of resin phenol-formaldehyde (6, 9 and 12%) and 1% of paraffin. The nominal density of the panels was 0.7 g/cm3 and the cycle of pressing consisted in a pressure of 3.92 MPa under a temperature of 180°C for 8 minutes. By the results it was possible to observe that the physical properties of the particleboard have a linear relationship decreasing with the increase in the level of resin, and increasing with the increase in the percentage of coffee husks, showing higher values of water absorption and thickness swelling. The mechanical properties show a linear relationship growing with the increase of resin level, and decreasing with a reduction the percentage of coffee husk association. The way that the search was conducted, the incorporation of the Coffee husks harms the quality of the panels produced.

Efeito da associação de bagaço de cana, do tipo e do teor de adesivo na produção de painéis aglomerados.

Este trabalho teve como objetivo avaliar o efeito da associacao de bagaco de cana, tipo e teor de adesivo nas propriedades fisico-mecânicas de paineis aglomerados com madeira de pinus spp. O delineamento experimental se constituiu de um esquema fatorial 3x2x3, sendo tres porcentagens de substituicao de madeira de pinus por bagaco de cana - 25, 50 e 75%; dois tipos de adesivos - fenol-formaldeido (FF) e ureia-formaldeido (UF); e tres teores de adesivo - 6, 9 e 12%. O ciclo de prensagem utilizado foi de pressao de 40 kgf/cm2, temperatura de 160°C para UF e de 180°C para FF, e por um tempo de 8 minutos. Mediante os resultados pode-se concluir que: 1) Para a porcentagem de associacao de bagaco de cana, nas propriedades em que foi observado efeito significativo, a tendencia foi de diminuicao da qualidade dos paineis a medida que se aumenta a quantidade de associacao de bagaco de cana; 2) O adesivo UF se mostrou estatisticamente igual ou superior a FF em todas as propriedades avaliadas; 3) Os teores de adesivo apresentaram efeito significativo para todas as propriedades analisadas, sendo que, com excecao da propriedade ligacao interna, em todas as outras propriedades o teor de 12% foi estatisticamente superior a 6%, e ainda igual ou superior a 9%.

Polyester Composites Reinforced with Corona-Treated Fibers from Pine, Eucalyptus and Sugarcane Bagasse

This study aims to evaluate plant fibers that were surface activated with NaOH and corona discharge before incorporating in ortho unsaturated polyester-based fiber composites. It demonstrates the potential use of lignocellulosic particles, especially eucalyptus that presented the higher values for all the mechanical properties analyzed. The corona discharge treatment increased impact strength and tensile strength of the composites, and decreased water absorption. SEM images showed that the surface activation generally improved the interfacial adhesion between fibers and polyester matrix. Corona treatment may depolymerize the lignocellulosic material and smaller fragments may actually help increase the interaction with the polyester.

Babassu nut residues: potential for bioenergy use in the North and Northeast of Brazil

Babassu is considered the largest native oil resource worldwide and occurs naturally in Brazil. The purpose of this study was to evaluate the potential of babassu nut residues (epicarp, mesocarp and endocarp) for bioenergy use, especially for direct combustion and charcoal production. The material was collected in the rural area of the municipality of Sítio Novo do Tocantins, in the state of Tocantins, Brazil. Analyses were performed considering jointly the three layers that make up the babassu nut shell. The following chemical characterizations were performed: molecular (lignin, total extractives and holocellulose), elemental (C, H, N, S and O), immediate (fixed carbon, volatiles and ash), energy (higher heating value and lower heating value), physical (basic density and energy density) and thermal (thermogravimetry and differential thermal analysis), besides the morphological characterization by scanning electron microscopy. Babassu nut residues showed a high bioenergy potential, mainly due to their high energy density. The use of this biomass as a bioenergy source can be highly feasible, given their chemical and thermal characteristics, combined with a low ash content. Babassu nut shell showed a high basic density and a suitable lignin content for the sustainable production of bioenergy and charcoal, capable of replacing coke in Brazilian steel plants.

Use of Coffee Plant Stem in the Production of Conventional Particleboards

When the productivity of a coffee plantation drops considerably, the crop must be renewed. In this case, the removed plants become residues to be discarded. This work aimed to verify the utilization of the coffee plant stem in the production of conventional particleboards. The basic density and chemical composition of the coffee stem was obtained. 3 particleboards were produced with urea-formaldehyde at 6% and paraffin at 1%. The target density of the panels was 0.600 g/cm3. The pressing cycle used was: pressure of 0.32 MPa, temperature of 160°C and time of 8 minutes. Apparent density (AD), water absorption (WA), thickness swelling (TS) after 2 and 24 hours immersion and thickness non-return rate (TNRR) were the physical properties obtained. Mechanical properties evaluated were parallel compression (CP), static bending (MOE and MOR) and internal bonding (IB). The average basic density, total extractive, lignin, mineral components and holocelluloses contents obtained were 0.581gcm-3, 11%, 28%, 2% and 59%, respectively. The average values of the physical and mechanical properties of the boards, followed by their standard deviation were: AD= 0.577 gcm-3 (0.018); CR = 1.03 (0.12); WA_2h = 55% (2.3); WA_24r = 76% (2.5); TS_2h = 32% (4.4); TS_24h = 59% (7.8); TNRR = 62 % (2.0); IB = 0.43 MPa (0.03); CP = 4.9 MPa (0.23); MOE = 1324.4 MPa (1.02); and MOR = 13.4 MPa (1.02). Coffee stem conventional particleboards presented poor physical resistance. On the other hand, they may be commercialized for general uses in dry-conditions.

TRANSFORMAÇÃO DA CASCA DE ARROZ EM UM PRODUTO DE MAIOR VALOR AGREGADO: POTENCIAL PARA A PRODUÇÃO DE PAINÉIS PARTICULADOS

This work aimed to evaluate the quality of particleboards made with different formulations, varying adhesive content and rice husk ( Oryza sativa L .) proportions added to Cunninghamia lanceolata wood. Three adhesive contents (6, 9 and 12%) and three proportions of rice husk added to wood (25, 50 and 75%) were combined resulting in 9 formulations of particleboards. In order to analyze the influence of each raw material in the final quality of the boards, their chemical composition was determined, including extractive, ash, lignin and holocellulose contents. Regarding the particleboards, the following physical and mechanical properties were evaluated: water absorption (WA), thickness swelling (TS), internal bonding (IB), parallel compression (PC), modulus of elasticity (MOE) and modulus of rupture (MOR) in static bending. For both mechanical and physical properties, average values showed that lower rice husk proportions and higher adhesive contents induced to better performance. Low lignin and high ash contents found in rice husks negatively influenced particleboard quality. Among the formulations tested, the inclusion of 25% of rice husk and 9% urea-formaldehyde presented the best results. Particleboards produced in this work are potential alternatives for general applications in dry conditions that do not require high mechanical resistance. Nevertheless, the process and formulations need to be adjusted in order to reach the requirements for more demanding structural applications.

Properties of osb panels with veneer inclusion

This work aimed to evaluate the effect of veneer inclusion with different wood species, and also different levels of pressing pressure applied in the moment of the veneer inclusion over physicalmechanical properties of already consolidated OSB (Oriented Strand Board) panels. Treatments were arranged in factorial scheme 4 x 2 (four wood types for veneer inclusion – Pinus oocarpa, Eucalyptus urophylla, Parkia gigantocarpa and Brosimum parinariodes; and two pressing pressures – 1 and 2 MPa) and also a control (without veneer inclusion). Veneer inclusion was made with 180 g.cm-2 phenol formaldehyde adhesive, in a simple glue line, perpendicular to the external layer of panels. The pressing cycle used was 150oC for 4 minutes under pressure 1 or 2 MPa pressure depending on the pre-established treatment. It was possible to conclude that: 1) Veneer inclusion with pines, eucalypt and amapa promoted significant improvements for physical-mechanical properties of OSB panels, highlighting eucalypt and amapa; 2) There was not a significant effect of the level of pressing pressure over mechanical properties of OSB with veneer inclusion; and 3) Regarding physical properties, the highest pressure level (2 MPa) promoted a negative effect in some properties, while veneer inclusion the pressure of 1 MPa generally promoted significant improvement of all physical properties.

Thermal properties of chipboard panels made of sugar cane bagasse (Saccharum officinarum L)

The sugar cane bagasse is the most abundant agricultural residue produced in Brazil. It can be used for the production of chipboard panels and as constructive components for several types of environments. The substitution of timber for the bagasse minimizes environmental impacts and contributes to the generation of a new product with lower density and lower thermal conductivity which can improve the thermal conditioning of buildings. This study aims at determining the heat flow through chipboard panels made of sugarcane bagasse and comparing these chipboard panels with similar ones made of Pinus and Eucalyptus. The results show that the heat flow during the heating of the panels is lower for the panels made of sugar cane bagasse and the heat accumulation promoted by this panel is greater than by others. Therefore this product may be suitable to be used as liners, between cavity walls, partition walls and more.

Acoustic Characterization of Sugarcane Bagasse Particleboard Panels (Saccharum officinarum L)

The use of sugarcane bagasse minimizes the environmental impact and contributes to the creation of a new product with low density, good sound absorption capacity and can improve the acoustic conditions of buildings. The goal of this study aims to determine the intensity response of sugarcane bagasse particleboard panels’ sound absorption and compare them with particleboard panels of the species Pinus sp. and Eucalyptus sp. To accomplish this, the sound pressure levels in different frequency bands were analyzed. The results showed higher sound absorption between the low and high frequency bands for the three types of panels, with an absorption peak in 315 Hz identifying the characteristic frequency of resonance from these materials. However, the sugarcane bagasse panel presented differently than the others, with a greater retention of sound energy in the medium frequency band between 630 Hz and 1,000 Hz with a maximum absorption at 55 dB at the frequency of 800 Hz. Keywords: sugarcane bagasse, particleboard, sound absorption, acoustics

Inclusion of Lignocellulosic Fibers in Plastic Composites

Solutions for the production of sustainable plastics have motivated the scientific community to search for new alternatives for the replacement of raw materials from non-renewable sources such as glass fibers. Therefore, plant fibers appear to be a feasible alternative, since they present low cost, suitable mechanical strength, wide availability, as well as are renewable. This work aimed to evaluate the replacement of glass fibers by lignocellulosic fiber in plastic composites used in civil construction sectors. The resin used was ortho unsaturated polyester. Three plant fibers were tested (sugar cane bagasse, eucalypt and pine) with and without chemical modification. The chemical modifications were performed with sodium hydroxide. The composites were evaluated by their physical and mechanical properties. The initial results showed the potential of using plant fiber in the production of fiber-reinforced plastic composites. Keywords: plant fibers, residues, polyester resin