Papers by Author: Lina Bufalino

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Authors: Andréa A.R. Corrêa, Lina Bufalino, Thiago de Paula Protásio, Marcelo X. Ribeiro, Danilo Wisky, Lourival Marin Mendes
Abstract: The raw mud brick (adobe) is a millenary technology that awakens a wide interest in ecologic and non-conventional constructions. Some advantages are low cost, thermal comfort and minimum environmental impact. For better use, it is important to improve their mechanical properties. Dynasolo DS-328® is a chemical stabilizer used in soil compression for road paving and it is similar to termite saliva. This composition is based on vegetal oils. It is a high-concentrated liquid product, water soluble, non-toxic, non-corrosive, and non-flammable. The cohesive properties promote the investigation about the incorporation of this product in adobe composition. Therefore, this work aimed to evaluate synthetic termite saliva" incorporation to adobes at four different concentrations: 1:2000; 1:1500; 1:1000 and 1:500. The reagent is an aluminum sulfate at 1:5000 for all treatments. The soil is a Red Latosol cambisol corrected to 50% fine sand fraction. Soil bulk density, particle density and total pore volume were: Ds = 1.42 kg/dm3, Dp = 2.62 kg/dm3 and VTP = 45.8%. The soil Atterberg limits were: LL (liquid limit) 55.44%; PL (plastic limit) 34.58%; SL (shrinkage limit) 21.67%; and PI (plasticity index) 20.86%. The ideal moisture content was variable, ranging from 50% to 40% according synthetic termite saliva" increase. Adobes were submitted to compression and bending resistance tests. This research confirmed that synthetic termite saliva" incorporation improved the adobe compressive resistance and chose the treatment 1:1500 because it increased 20% this property.
Authors: Ricardo Gabriel de Almeida Mesquita, Gustavo H. Denzin Tonoli, Rafael Farinassi Mendes, Antônia Amanda da Silva César, Lina Bufalino, Lourival Marin Mendes
Abstract: 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
Authors: Lourival Marin Mendes, Rafael Farinassi Mendes, G.H.D. Tonoli, Lina Bufalino, Fábio Akira Mori, José B. Guimarães Júnior
Abstract: The Brazilian market of wood panels is in a consolidation process and presents great dynamism, which requires the search for new alternative raw materials that may contribute in quantity and quality to the continuous increase of this economic sector. Transforming residues generated by Brazilian agricultural industry and forestry sector into high quality panels is an interesting solution for solving raw material demand problem. The present work aims to show the potential of different types of residues for panel production showed in several research works, which were conducted in the Experimental Unit of Panel Production (UEPAM) located at the Federal University of Lavras (UFLA), Minas Gerais state, Brazil. According to results obtained, sugarcane bagasse, candeia wood and castor oil bean husk were the most promissory residues for particleboard production among the materials studied.
Authors: Lina Bufalino, G.H.D. Tonoli, Tattiane Gomes Costa, Thiago de Paula Protásio, Alfredo Rodrigues Sena Neto, José Manoel Marconcini, Mário Guimarães Junior, Lourival Marin Mendes
Abstract: The aim of this work was to determine the best fibrillation intensity that should be used to produce high crystalline and thermal stable microfibrillated cellulose (MFC) and nanocellulose films from C. goeldiana veneer wastes. The number of passages (cycles) of cellulose suspension tested in grinder were 10, 20, 30 and 40. Important properties to be analyzed included changes in morphology from the raw wood to the nanocellulose films, increases/decreases in cellulose crystalline index for inference on biomaterial strength, and thermal behavior changes to support conclusions on biomaterials processing and application possibilities. After chemical treatments for cellulose isolation, mechanical shearing was applied to produce cellulose nanostructures; hence nanocellulose films could be successfully produced from C. goeldiana wood wastes. Influence of more refining cycles on thermal properties, indicated higher stability for 40-cycles nanocellulose films. In general, grinder refining process decreased crystalline index of cellulose.
Authors: Bárbara Maria Ribeiro Guimarães, Lina Bufalino, José Benedito Guimarães Jr., Rafael Farinassi Mendes, Lourival Marin Mendes, Gustavo H. Denzin Tonoli
Abstract: This work intends to verify the technical feasibility of NaOH treatment in particleboard manufacture made from banana pseudostem fibers. The particles were treated for a 24 hour period and subsequently washed with water to remove the product. The concentration used was NaOH at 0.5%. The adhesive used was urea - formaldehyde at 12%, the pressing cycle was 4 MPa, at 160 °C for 8 minutes. The water absorption after 2 hours immersion was 148.79% and 189.83% after 24 hours. Thickness swelling value after 2 hours was 54.96% and 74.05% after 24 hours. The results were above the literature values and the minimum values required by the CS 236-66 standard for swelling after 24 hours immersion.
Authors: Lina Bufalino, Leandro Afonso Caixeta, Thiago de Paula Protásio, Mario Vanoli Scatolino, Ricardo Gabriel de Almeida Mesquita, Lourival Marin Mendes, Gustavo Henrique Tonoli, José Manoel Marconcini
Abstract: Two pathways for chemical modification of wastes from an Amazon hardwood species named Cordia goeldiana were proposed in this work. Variations in reaction time (2 h or 0.5 h) and temperature (80 and 150 °C), besides reaction medium (mechanical stirring or pressurized closed system) were tested for alkali treatment. NaOH at 5% was kept for both conditions. Afterwards, bleaching with H2O2 and NaOH was performed, but reaction conditions were held constant for both pathways. In general, the mild alkali treatment resulted mainly in the removal of extractives and hemicelluloses from the raw sawdust. The onset temperature and crystalline index increased. On the other hand, the use of higher pressure and temperature in alkali treatment at closed system had a remarkable lignin removal and crystalline index increase without changing cellulose polymorphism as the main effects, but thermal stability became lower. Apart from mineral residues removal, bleaching had negligible effects on fiber properties, suggesting that this procedure could be avoided.
Authors: Antônia Amanda da Silva César, Lina Bufalino, Laurenn Borges de Macedo, Ricardo Gabriel de Almeida Mesquita, Thiago de Paula Protásio, Lourival Marin Mendes
Abstract: 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.
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