ABSTRACT This study assessed the properties of particleboard produced from the replacement of urea formaldehyde with cassava starch. Cassava starch (CS) and urea-formaldehyde (UF) were mixed at percentages of 100/0, 90/10, 70/30, 50/50, and 0/100, respectively. The mixture was added to the wood particles at 15% adhesive content based on the weight of oven-dried particles. Particleboards of sizes 20 mm × 300 mm × 300 mm and a targeted density of 600 kg m–3 were manufactured by hot-pressing at 170 °C, compacting pressure 3.5 MPa for 8 min. Physical and mechanical properties (density, thickness swelling, water absorption, static bending, and hardness) were tested. The physical and mechanical properties also increased in the highest proportions of UF. Comparatively, manufactured with 50% CS + 50% UF, it performed better in all the evaluated properties. Thus, it could adopt the latter mixed ratio in the industry to reduce the quantity and cost of UF and its environmental emissions. The results obtained were adequate and in conformity with international standards. Hence, it could mix cassava starch and urea formaldehyde adhesives in different ratios to get desirable properties. It is possible to conclude that cassava starch could be considered a sustainable alternative adhesive. (CS ureaformaldehyde (UF 1000 100 0 100/0 9010 90 10 90/10 7030 70 30 70/30 5050 50 50/50 0100 0/100 respectively 15 ovendried oven dried 2 60 m3 m 3 m– hotpressing hot pressing 17 C °C 35 5 3. min density, (density swelling absorption bending hardness tested Comparatively Thus emissions standards Hence 100/ 901 9 1 90/1 703 7 70/3 505 50/5 010 0/10 6 90/ 70/ 50/ 01 0/1 0/

Abstract This research aimed to evaluate the production of charcoal and wood vinegar in a mini-rectangular kiln equipped with a condenser and vertical smoke burner. The kiln had a chimney, a condenser and a vertical smoke burner. The logs were 0.90 m long and had characterized. Ten carbonization runs were conducted to evaluate the kiln’s performance, determining the gravimetric yields in charcoal, wood vinegar, and gases. The carbonization process took three days to conclude and four days to cool the charcoal. The results showed that the average yields for charcoal, wood vinegar, and gases were 34.0, 31.2, and 34.8%, respectively. The charcoal produced, despite the use of moderate-density wood, demonstrated favorable characteristics. The moisture content, ash content, volatile materials, and higher calorific values all fell within the ideal ranges. This, coupled with a good yield, confirms the technical viability of the system as an alternative for small producers. minirectangular mini rectangular burner chimney 090 0 90 0.9 characterized kilns s performance 340 34 34.0 312 31 2 31.2 348 8 34.8% respectively produced moderatedensity moderate density characteristics content materials ranges yield producers 09 9 0. 3 34. 31. 34.8

RESUMO A modificação térmica da madeira é um processo que altera sua composição química, visando melhorar propriedades tecnológicas como estabilidade dimensional, redução do teor de umidade de equilíbrio, homogeneidade ou cor. Neste contexto, este estudo teve como objetivo avaliar a colorimetria e as propriedades químicas da madeira de Parkia pendula (angelim-saia) e Simarouba amara (marupá) modificada termicamente por diferentes métodos. Foram avaliados três tratamentos: T1 (pré-tratamento em estufa por uma hora a 120 °C e tratamento em estufa a 180 °C por três horas); T2 (pré-tratamento em autoclave a 125 °C por três horas sob 1,2 kgf cm-2 e tratamento em estufa a 180 °C por três horas); T3 (sem pré-tratamento, com tratamento da amostra em óleo vegetal). A madeira termicamente modificada foi avaliada em relação à madeira não tratada quanto à composição química estrutural (extrativos, lignina, holocelulose e teor de cinzas), parâmetros colorimétricos definidos através do sistema CIELAB (Commission Internationale de l´Eclairage) e variação total de cores. Detectamos um aumento significativo no teor de extrativos e uma diminuição no teor de holocelulose e lignina em T3 para ambas espécies, o que pode ser explicado pela impregnação de óleo nas amostras de madeira. A modificação térmica provocou o escurecimento superficial da madeira de ambas espécies, que foi mais pronunciado em P. pendula. Apesar da alteração colorimétrica, quimicamente não houve prejuízos para as madeiras. dimensional equilíbrio cor contexto angelimsaia angelim saia (angelim-saia marupá (marupá métodos tratamentos T prétratamento pré 12 C 18 horas) 1 2 1, cm2 cm cm- sem prétratamento, tratamento, pré-tratamento vegetal. vegetal . vegetal) extrativos, (extrativos cinzas, cinzas , cinzas) Commission l´Eclairage lEclairage l Eclairage cores espécies P colorimétrica madeiras

ABSTRACT The thermal modification of wood is a process that alters its chemical composition, aiming to improve technological properties such as dimensional stability, reduction of equilibrium moisture content, homogeneity, or color. In this context, this study aimed to evaluate the colorimetry and chemical properties of the wood of Parkia pendula (angelim-saia) and Simarouba amara (marupá) that was thermally modified by different methods. Three treatments were evaluated: T1 (pre-treatment in an oven for one hour at 120 °C and treatment in an oven at 180 °C for three hours); T2 (pre-treatment in an autoclave at 125 °C for three hours under 1.2 kgf cm-2 and treatment in an oven at 180 °C for three hours); and T3 (without pre-treatment, with sample treatment in vegetable oil). The thermally modified wood was evaluated in relation to untreated wood for structural chemical composition (extractives, lignin, holocellulose and ash content), colorimetric parameters defined through the CIELAB (Commission Internationale de l´Eclairage) system and total color variation. We detected a significant increase in extractives content and a decrease in holocellulose and lignin content in T3 for both species, which can be explained by the impregnation of oil in the wood samples. The thermal modification caused the surface darkening of the wood of both species, which was more pronounced in P. pendula. Despite the colorimetric change, there was no chemical damage to the wood. stability homogeneity context angelimsaia angelim saia (angelim-saia marupá (marupá methods T pretreatment pre 12 C 18 hours) 1 2 1. cm2 cm cm- without pretreatment, treatment, pre-treatment oil. . oil) extractives, (extractives , content) Commission l´Eclairage lEclairage l Eclairage variation species samples P change

ABSTRACT Background: The production of cellulose microfibrils/nanofibrils (CMF/CNF) has attracted increasing attention in recent decades due to their excellent barrier, mechanical, and surface chemistry properties. However, large-scale industrial production of CMF/CNF has been a major challenge due to their high energy consumption, limiting their application. In this context, in recent years many studies have focused on developing pre-treatments designed to facilitate the fibrillation of CMF/CNF by reducing energy consumption during their production. This review highlights the latest advances in the use of silicates as chemical pre-treatments for CMF/CNF production, covering the main aspects related to the effects of chemical modification on the production and the properties of materials for application in biodegradable packaging. Results: Energy consumption reductions of up to 30% were achieved by pretreating cellulose pulps using silicates. In addition, the pre-treatments resulted in smaller CMF/CNF diameters and greater individualization of the nanofibrils. Studies evaluating the thermal stability, hydrophobicity, mechanical properties, and porosity of CMF/CNF pre-treated with silicates have reported promising results. The application of CMF/CNF pretreated with calcium and magnesium silicates in cardboard coating resulted in packaging with low water vapor permeability and high ductility. Conclusion: Silicates interact well with cellulose surfaces, making them a promising material for the chemical pre-treatment of CMF/CNF. Furthermore, the modification by silicates could be an interesting strategy for expanding the use of CMF/CNF in the development of new products. Background microfibrilsnanofibrils microfibrils nanofibrils CMFCNF CMF CNF (CMF/CNF barrier However largescale large scale context pretreatments pre treatments Results 30 addition stability hydrophobicity treated results ductility Conclusion surfaces pretreatment treatment Furthermore products 3

Abstract Knowledge of the characteristics and durability of every wood species is essential so it can be better directed for the correct harnessing. In a wood rot field test, this work aimed to determine the natural durability of timber species from the Brazilian dry forest, Mimosa tenuiflora and Mimosa caesalpiniaefolia . The slats were buried in the ground up to half their length and distributed in the field according to a completely randomized experimental design. Annual assessments were performed to determine the deterioration rate. Furthermore, mass loss and condensed tannin content were quantified. The condensed tannin content found for the species was 4.40% for M. caesalpiniaefolia and 3.99% for M. tenuiflora . The results of 3 years of evaluation of the test make it possible to understand that both species presented durable wood, where M. caesalpiniaefolia presented a deterioration rate of 77.27%, while M. tenuiflora presented 66.27%, making them of high natural durability. harnessing forest design Furthermore quantified 440 4 40 4.40 M 399 99 3.99 7727 77 27 77.27% 6627 66 66.27% 44 4.4 39 9 3.9 772 7 2 77.27 662 6 66.27 4. 3. 77.2 66.2 77. 66.

Abstract The aim to evaluate the raw material (agroforestry residues) for particleboard manufacture from the: pseudostem of Musa paradisiaca; the stem and pods of Theobroma cacao; and the sawdust of Ceiba pentandra. The particleboards produced from these cellulosic residues are mixed with cassava starch’s natural adhesive and urea formaldehyde’s synthetic adhesive. The results indicate that lignin, α-cellulose, hemicellulose, and extractives ranged from 6.2–19.0%, 41.4–50.2%, 24.4–31.5%, and 6.8–18.8% respectively and they were significantly different from each other. Additionally, tannins, alkaloids, saponins, flavonoids, phenols, glycosides, and sterols were the phytochemicals present in biomass materials in different quantities. Also, carbon, oxygen, nitrogen, and boron were the elementals significantly present in the manufactured particleboards in the range of 35.3–52.8, 30.2–43.0, 4.2–24.0, and 3.2–9.9 percentage concentration respectively. As for the mechanical properties, it was verified that the cellulose content influenced 96.5% of the variability of the modulus of rupture (MOR) values. Understanding the distribution, functional properties, and impact of biomass organic, phytochemicals and elemental constitutions is an impetus to the improvement of processes with higher retention of these constitutions in the utilization of agroforest residues in the particleboard industry. These chemical compositions of the residues under study contributed largely to the characteristics of the manufactured particleboards. agroforestry paradisiaca cacao pentandra starchs starch s formaldehydes formaldehyde lignin αcellulose, αcellulose α cellulose, α-cellulose hemicellulose 62190 6 2 19 0 6.2–19.0% 414502 41 4 50 41.4–50.2% 244315 24 31 5 24.4–31.5% 68188 8 18 6.8–18.8 other Additionally tannins alkaloids saponins flavonoids phenols glycosides quantities Also carbon oxygen nitrogen 353528 35 3 52 35.3–52.8 302430 30 43 30.2–43.0 42240 4.2–24.0 3299 9 3.2–9. properties 965 96 96.5 MOR (MOR values distribution organic industry 6219 1 6.2–19.0 41450 41.4–50.2 24431 24.4–31.5 6818 6.8–18. 35352 35.3–52. 30243 30.2–43. 4224 4.2–24. 329 3.2–9 96. 621 6.2–19. 4145 41.4–50. 2443 24.4–31. 681 6.8–18 3535 35.3–52 3024 30.2–43 422 4.2–24 32 3.2– 62 6.2–19 414 41.4–50 244 24.4–31 68 6.8–1 353 35.3–5 302 30.2–4 42 4.2–2 3.2 6.2–1 41.4–5 24.4–3 6.8– 35.3– 30.2– 4.2– 3. 6.2– 41.4– 24.4– 6.8 35.3 30.2 4.2 6.2 41.4 24.4 6. 35. 30. 4. 41. 24.

ABSTRACT The attempt to face the limitations of wood-based materials, especially concerning the relationship with water, is still a considerable gap in research on this subject. The present work proposes the accomplishment of thermal treatment in fiberboard-type hardboard, using different temperatures and times, to evaluate the effect on the physical-mechanical properties. The parameters of the heat treatment were temperatures of 120 and 160 °C and times of 20 and 40 min. The hardboards were individually heat treated in a kiln. The characterization was performed from physical tests such as bulk density, moisture content, water absorption (2 and 24 h), thickness swelling (2 and 24 h); and mechanical properties of flexural strength. The treatment with a temperature of 160 °C for 40 min showed the lowest values of water absorption in 24 h (34%). Thickness swelling was lower compared to control, for all the treatments applied. Regarding flexural strength, the treatment that adopted the 160 °C for 20 min showed the highest MOR value (26.3 MPa). In general, the performance of heat treatments positively influenced the physical and mechanical properties of the hardboards, being an interesting alternative in the development of products for applications in internal environments. woodbased wood based materials subject fiberboardtype fiberboard type hardboard physicalmechanical 12 16 C 2 4 kiln density content ( h, , h) strength 34%. 34 34% . (34%) control applied 26.3 263 26 3 (26. MPa. MPa MPa) general environments 1 (34% 26. (26 (34 (3

ABSTRACT Background: Determining the basic density of the wood is usually defined as a simple process, but it requires caution and the operator’s skill to avoid errors in the analysis. In addition, it involves sample preparation and time to saturate the wood until obtaining the dry sample mass. The development of alternative measurement techniques could reduce the time to obtain the results and provide reliable values. Therefore, this study aimed to develop multivariate models to estimate the basic density of native woods using near-infrared spectra (NIR). Basic densities were determined by the water immersion method, and the values were associated with NIR signatures. Spectra were directly collected on the wood transversal and radial faces with an integrating sphere. Partial least squares regression (PLS-R) was calibrated and validated to estimate basic density based on spectral signatures. Results: In the cross-validation and prediction of the models, the results were promising. The coefficients of determination varied from 0.87 to 0.93 with a standard error of 0.01 %. The partial least squares discriminant analysis (PLS-DA) efficiently classified the wood species. The ratio of performance to deviation obtained satisfactory values, a minimum of 2.81 and a maximum of 4.20. Conclusion: The statistical parameters of the models based on NIR spectra showed potential for density measurements in floors, furniture, and solid wood products. Background process operators operator s addition mass Therefore nearinfrared near infrared NIR. . (NIR) method signatures sphere PLSR PLS R (PLS-R Results crossvalidation cross validation promising 087 0 87 0.8 093 93 0.9 001 01 0.0 % PLSDA DA (PLS-DA species 281 2 81 2.8 420 4 20 4.20 Conclusion floors furniture products (NIR 08 8 0. 09 9 00 28 2. 42 4.2 4.

ABSTRACT Were characterized microstructurally and mechanically the Ti-6Aℓ-4V alloy obtained through powder metallurgy in an uncontrolled atmosphere, varying the sintering parameters, arose. The samples were compacted in a uniaxial press at 874 MPa, 999 MPa, and 1124 MPa, and sintered without a protective atmosphere or vacuum, at 675 °C, 750 °C, and 850 °C. When sintering the material, the oxides influenced the results due to titanium’s high affinity for interstitial elements, promoting increased density and high hardness values. Based on the results, the treatment carried out at a pressure of 1124 MPa and a temperature of 750 °C showed the highest hardness in the beta phase (β), with a value of 1165.1 HV. In the alpha phase (α), the highest value was 1321.3 HV, presented by the treatment performed at a pressure of 999 MPa and a temperature of 850 °C. The high hardness values observed in the alloy are associated with the reinforcement promoted by the dissolution of Fe atoms. Materials with high hardness values use in the aerospace and biomedical industries, which always look for better mechanical resistance results, thus increasing their products’ useful life and applicability. Ti6Aℓ4V TiAℓV Ti 6Aℓ 4V Aℓ V parameters arose 87 99 112 vacuum 67 C 75 85 material titaniums titanium s elements β, β , (β) 11651 1165 1 1165. HV α, α (α) 13213 1321 3 1321. atoms industries products applicability 8 9 11 6 7 (β 116 (α 132 13

RESUMO Foram caracterizadas micro estruturalmente e mecanicamente a liga Ti-6Aℓ-4V obtida através da metalurgia do pó em atmosfera não controlada variando os parâmetros de sinterização. As amostras foram compactadas em uma prensa uniaxial à 874 MPa, 999 MPa e 1124 MPa, e sinterizadas sem atmosfera protetora ou vácuo, nas temperaturas de 675 °C, 750 °C e 850 °C. Ao sinterizar o material, houve influência dos óxidos nos resultados devido à alta afinidade que o titânio tem por elementos intersticiais, promovendo um aumento na densidade e elevados valores de dureza. A partir dos resultados verificou-se que o tratamento realizado na pressão de 1124 MPa e temperatura de 750 °C foi o que apontou a maior dureza na fase beta (β), sendo o valor de 1165,1 HV. Na fase alfa (α), o maior valor foi de 1321,3 HV, apresentado pelo tratamento realizado na pressão de 999 MPa e temperatura de 850 °C. Os elevados valores na dureza observados na liga estão associados ao reforço promovido pela dissolução átomos de Fe. Materiais com elevada dureza possuem uma vasta aplicação nas indústrias aeroespaciais e biomédicas, que buscam sempre por melhores resultados de resistência mecânica, aumentando assim a vida útil e a aplicabilidades de seus produtos. Ti6Aℓ4V TiAℓV Ti 6Aℓ 4V Aℓ V sinterização 87 99 112 vácuo 67 C 75 85 material intersticiais verificouse verificou se β, β , (β) 11651 1165 1 1165, HV α, α (α) 13213 1321 3 1321, Fe biomédicas mecânica produtos 8 9 11 6 7 (β 116 (α 132 13

ABSTRACT Economic development based on cleaner industrial technologies has been increasingly studied in recent years. Cementitious composites reinforced with lignocellulosic fibers can be a sustainable alternative for use in engineering. The study aimed to evaluate the technological properties of cementitious composites produced from natural and industrial coconut fiber to compare the reinforcement with wood particles. Physical tests (density, water absorption, and thickness swelling) and mechanical tests (static bending) were carried out in four treatments, which varied the fiber and cement contents. It was found that treatment with natural coconut fiber had the lowest density value, 0.59 g/cm3, and treatment with industrial coconut fiber had the lowest water absorption value for the times and times of 2 and 24 h, 0.19, and 0.38%, respectively, and the treatment with wood particles, the highest values of modulus of elasticity and rupture, 1,897 MPa and 2.44 MPa. The study of the use of lignocellulosic materials as protection in cementitious composites is essential for applications in building constructions to reduce the environmental impacts generated by the generation of waste and use of non-renewable materials and to promote sustainable development. years engineering particles density, (density swelling static bending treatments contents 059 0 59 0.5 gcm3 gcm g cm3 cm g/cm3 h 019 19 0.19 038 38 0.38% respectively rupture 1897 1 897 1,89 244 44 2.4 nonrenewable non renewable 05 5 0. g/cm 01 0.1 03 3 0.38 189 89 1,8 4 2. 0.3 18 8 1,

Resumo Objetivou-se avaliar o efeito do tratamento térmico nas propriedades físicas da madeira de Buchenavia sp. Os tratamentos térmicos foram feitos em temperaturas de 180 °C e 200 °C durante 2 h. Avaliou-se a densidade aparente (AD), densidade básica (BD), porosidade (Ф), perda de massa, contração longitudinal (LS), radial (RS), tangencial (TS) e volumétrica (VS) e fator anisotrópico (AF). Os menores valores de densidade básica (0,67 g cm -3 ), densidade aparente (0,77 g cm -3 ) e porosidade (43,3%) foram observados para a madeira tratada em temperatura de 200 °C. As perdas de massa foram crescentes com o aumento da temperatura e os maiores valores foram observados na condição de 200 °C (9,3%). A LS e o AF não foram afetados pelos tratamentos térmicos. Os valores médios para RS (3,1%), TS (5,1%) e VS (9,1%) foram reduzidos após a realização dos tratamentos térmicos nas temperaturas de 180°C e 200 °C, que não diferiram entre si. Os tratamentos térmicos foram capazes de diminuir a instabilidade dimensional da madeira de Buchenavia sp. Os tratamentos térmicos potencializam o uso de madeiras da Amazônia de menor prestígio no mercado no contexto da construção civil.

Abstract This work aimed to evaluate the effect of heat treatment on the physical properties of wood from Buchenavia sp. The heat treatments were carried out at temperatures of 180 °C and 200 °C for 2 h. Apparent density (AD), basic density (BD), porosity (Ф), mass loss, longitudinal (LS), radial (RS), tangential (TS) and volumetric (VS) shrinkages and anisotropic factor (AF) were determined. The lowest values of basic density (0.67 g cm-3), apparent density (0.77 gcm-3), and porosity (43.3%) were observed for the wood treated at a temperature of 200 °C. Mass losses increased with increasing temperature and the highest values were observed under the condition of 200 °C (9.3%). The LS and AF was not affected by heat treatments. The mean values for RS (3.1%), TS (5.1%), and VS (9.1%) were reduced after the performance of heat treatments at temperatures of 180°C and 200°C, which did not differ from each other. The thermal treatments were able to reduce the dimensional instability of Buchenavia sp. Thermal treatments enhance the use of less prestigious Amazonian woods in the civil construction market.

RESUMO A durabilidade natural da madeira é essencial para a definição de seu uso, e essa propriedade pode ser potencializada com o tratamento químico adequado da madeira. Assim, o objetivo deste trabalho foi avaliar a resistência da madeira de Jacaranda copaia modificada quimicamente por acetilação a cupins e fungos apodrecedores. Cinco tratamentos experimentais foram avaliados: acetilação por 2, 4, 6 e 8 horas e um controle (não acetilado). A acetilação foi realizada por imersão das amostras de madeira em anidrido acético a 90°C. Amostras acetiladas e controle foram submetidas à ação de cupins xilófagos (Nasutitermes sp.) e fungos apodrecedores (Gloeophyllum trabeum e Trametes versicolor). O processo de acetilação aumentou significativamente a resistência da madeira de Jacaranda copaia ao ataque dos organismos xilófagos. Não houve perda de massa após exposição aos cupins da madeira em nenhum dos tratamentos de acetilação, enquanto na madeira controle a perda de massa foi de 9,5%. Em relação aos fungos em decomposição, ocorreu perda de massa em todos os tratamentos. Os tratamentos químicos mais eficientes foram os de acetilação por 6 e 8 horas, elevando a classe de resistência da madeira de Jacaranda copaia para altamente resistente.

ABSTRACT The natural durability of the wood is essential for the definition of its use, and this property can be enhanced with the proper chemical treatment of the wood. Thus, the objective of this study was to evaluate the resistance to termites and decay fungi of Jacaranda copaia wood chemically modified through acetylation. Five experimental treatments were assessed: acetylation for 2, 4, 6 and 8 hours and a control (non-acetylated). The acetylation was carried out by immersing wood samples in acetic anhydride at 90 °C. Acetylated and control samples were subjected to the action of xylophagous termites (Nasutitermes sp.) and decaying fungi (Gloeophyllum trabeum and Trametes versicolor). The acetylation process significantly increased the resistance of Jacaranda copaia wood to the attack of the xylophagous organisms. There was no mass loss after exposure to termites of the wood in any of the acetylation treatments, while in the control wood, mass loss was 9.5%. Regarding the decaying fungi, mass loss occurred in all treatments. Acetylation for 6 and 8 hours were the most efficient chemical treatments, increasing the resistance class of the Jacaranda copaia wood to highly resistant.

RESUMO O Brasil se destaca no cenário internacional em relação a produção de celulose de fibra curta. Apesar da grande biodiversidade brasileira, essa produção está baseada em clones de espécies exóticas de Eucalyptus. Nesse contexto, pode haver grande potencial na avaliação de novas fontes de fibras da flora brasileira, incluindo a região amazônica. O presente estudo teve como objetivo avaliar o potencial tecnológico da madeira de Ochroma pyramidale (Malvaceae) para produção de celulose kraft. Indivíduos de quatro anos de idade foram colhidos em um plantio comercial para produção de serrados no Estado do Mato Grosso. Determinamos as propriedades químicas (teores de holocelulose, lignina Klason, lignina solúvel, extrativos e cinzas), físicas (massa específica e porosidade) e morfologia de fibras (comprimento e largura de fibras, diâmetro do lume, espessura e fração de parede, coeficiente de flexibilidade, índice de enfeltramento e de Runkel) da madeira. Na polpação kraft a carga alcalina aplicada variou entre 10 e 24%, com intervalo de 2%. A madeira de Ochroma pyramidale apresentou características favoráveis à produção de polpa celulósica, como dimensões apropriadas das fibras e baixos teores de lignina, extrativos e cinzas. Os teores de álcali ativo residual e pH do licor negro apresentaram relação crescente com a carga alcalina aplicada nos processos de polpação. O acréscimo da carga alcalina reduziu o rendimento em polpação, número kappa, teor de rejeitos e aumentou o teor de ácidos hexenurônicos.

ABSTRACT Brazil stands out in the international scenario in the production of short-fiber pulp. Despite the great Brazilian biodiversity, that production is based on exotic Eucalyptus clones. In this sense, there may be great potential in the assessment of new sources of fibers from the Brazilian flora, including the Amazon. The present study aimed to assess the technical potential of the wood of Ochroma pyramidale (Malvaceae) for the production of kraft pulp. Four-year-old trees were harvested from a commercial forest for lumber production in Mato Grosso state (Brazil). We determined the wood’s chemical compositions (holocellulose, Klason lignin, soluble lignin, extractives and ash contents), physical properties (density and porosity), and fiber morphology (fiber length, width and thickness, lumen diameter, wall fraction, coefficient of flexibility, and slenderness and Runkel ratios). The wood was subjected to pulping with an effective alkali charge ranging from 10 to 24%, with intervals of 2%. Ochroma pyramidale wood presented characteristics favorable to the production of cellulosic pulp, such as appropriate fiber dimensions and low lignin, extractives, and ash content. The amount of residual active alkali and pH of the black liquor were positively related to the increase of the alkali charge employed in the pulping process. The increase of alkali charge decreased the pulp yield, kappa number and waste content, and increased the hexenuronic acid concentration.

ABSTRACT Thermal treatment can modify undesirable characteristics of some woods, dimensional instability, and excessive water adsorption. The present research work aimed to assess the effect of thermal treatment on the physical properties of clone GG100 Eucalyptus wood. Wood samples were obtained from 9 year-old trees. Samples were subjected to three types of thermal treatment (T1, T2, and T3). In T1, the wood was kept in a laboratory kiln at 100 °C for 180 min. In T2, hydrothermal treatment was performed in an autoclave at 120 °C for 120 min. In T3, the combined autoclave and laboratory kiln treatments were employed. The properties evaluated were apparent density (ρa); mass loss (ML); longitudinal (βl), radial (βr), tangential (βt), and volumetric shrinkage (βv); anisotropic factor; and equilibrium moisture content. The treatments caused a decrease of ρa and increase of ML. The Equilibrium Moisture Content (EMC) was lowest for T3, and had a negative correlation with ML, βt, and ∆v. The Pearson correlation analysis indicated the results of the thermal treatments were similar, but T1 presented the lowest variation of the physical properties compared to the other treatments, giving it the best predictability for practical uses.

Abstract Wood in civil construction has restrictions regarding its external use due to the actions of natural weathering, which can represent a real risk because they modify the characteristics of this material. This study aimed to evaluate the superficial deterioration of Trattinnickia rhoifolia (amescla), Parkia pendula (angelim), Erisma uncinatum (cedar), Apuleia leiocarpa (garapeira), and Mezilaurus itauba (itaúba) wood specimens exposed to natural weathering. For this purpose, wood samples were submitted to outdoor exposure on a metal platform, without contact with the ground, for 360 days. Every 60 days, the wood surface was characterized by colorimetry (L*, a*, b*, C*, h, and ΔE), roughness (Ra, Rz, and Rt), and hardness Rockwell. A darkened surface (grayish color) on the wood was observed after natural weathering, indicated by the decrease in the colorimetric parameters L*, a*, and b*. E. uncinatum wood presented the lowest values of the total color change (ΔE). In addition to the discoloration, weathered wood presented the highest values of surface roughness and the lowest values of Rockwell hardness due to the occurrence of surface cracks. A. leiocarpa and M. itauba woods presented greater stability of roughness and Rockwell hardness throughout the outdoor exposure.

Resumo A madeira na construção civil apresenta restrições quanto ao seu uso externo devido às ações do intemperismo natural, que podem representar um risco real pois modificam as características desse material. Neste estudo objetivou-se avaliar a deterioração da superfície das madeiras de Trattinnickia rhoifolia (Amescla), Parkia pendula (Angelim), Erisma uncinatum (Cedro), Apuleia leiocarpa (Garapeira) e Mezilaurus itauba (Itaúba) expostas ao intemperismo natural. Para tanto, amostras de madeira foram expostas às intempéries em uma plataforma metálica, sem contato com o solo, durante 360 dias. A cada 60 dias realizou-se a caracterização da superfície das madeiras por meio da colorimetria (L*, a*, b*, C*, h e ∆E), rugosidade (Ra, Rz e Rt) e dureza Rockwell. A exposição ao intemperismo natural tornou a superfície das madeiras mais escurecidas (coloração acinzentada), resultante da redução dos parâmetros colorimétricos L*, a* e b*. A madeira de E. uncinatum apresentou os menores valores de variação total da cor (∆E). Além da descoloração, as madeiras intemperizadas tornaram-se mais rugosas e com menor dureza Rockwell, devido à formação de fissuras superficiais. As madeiras de A. leiocarpa e M. itauba apresentaram maior estabilidade da rugosidade e da dureza Rockwell durante o período de exposição às intempéries.