Bioactive molecules in wood extractives: Methods of extraction and separation, a review

Bioactive molecules are those capable of interacting with living organisms, causing changes in them. Wood extractives contain important amounts of these molecules, and some of them have good antioxidant and antimicrobial activity, which favors their use as preservatives. Several different extraction methods are employed to obtain the extractives, some of which have been used for a long time. However, these conventional methods have significant disadvantages, being the most important ones high solvent, energy, and time consumption. To overcome these drawbacks, new extraction techniques are being developed whose aim is also the optimization of the process. Separation techniques such as chromatography and molecular distillation allow extractives purification and the acquisition of the desired molecules. This review aims to provide an overview of the extraction and purification methods used for wood bioactive molecules. To this end, issues such as raw material, solvent type, solid/liquid ratio (SLR), temperature, pressure, and extraction time are discussed. The application of extractives as preservatives for low durability woods is also analyzed. The study concludes that the quality and quantity of bioactive molecules, besides depending on the raw material, are determined by the employed methods and solvents to obtain these molecules. Therefore, the choice of method and solvent is of fundamental importance to achieve the desired results.Mateus Berwaldt Santos would like to thank to the Federal Institute of Education, Science and Technology Sul-rio-grandense for granting him paid permission to complete his doctorate. Leyre Sillero would also like to thank to the Spanish Ministry of Universities for the Margarita Salas fellowship for the re-qualification of the Spanish university system financed by the European Union-Next Generation EU

Cement-wood composites : effects of wood species, particle treatments and mix proportion

The aim of this research was to investigate the effects of wood species, particle treatments and mix proportion on the physical (density) and mechanical (compressive strength and dynamicmodulus of elasticity) properties of cement-wood composites. Different mix proportions were investigated, based on the cement: wood ratio of 0.3:0.7, in volume, with Pinus elliottii and Eucalyptus grandis sawdust percentages of 0-100, 25-75, 50-50, 75-25 or 100-0. Sawdust particles were pre-treated with either lime or cement coating to improve cement and wood compatibility. Results show that wood species, particle treatments and mix proportions may influence the physical and mechanical properties of cement-wood composites. In general, results confirm that Eucalyptus sawdust and cement are naturally compatible and do not require any previous particle treatment to avoid compatibility problems

Síntese verde de nanopartículas de óxido de zinco

O interesse pela síntese de nanopartículas utilizando extratos vegetais vem crescendo nas últimas décadas, devido a não geração de resíduos de químicos tóxicos e condições mais brandas de síntese. O Brasil é um dos líderes em florestas plantadas, principalmente do gênero Eucalyptus, em razão disso o objetivo deste trabalho foi sintetizar nanopartículas de óxido de zinco utilizando extrato etanólico das folhas de Eucalyptus dunnii. As folhas foram secas e moídas para obtenção de pó, 10 g deste foram adicionadas em 100 mL de álcool etílico, a solução foi mantida em banho-maria a 80 ºC por 75 min, a solução foi filtrada para obtenção do extrato. Para a síntese utilizou-se 20 mL de extrato e 1,57 g de acetato de zinco, a solução foi mantida a 80 ºC sob agitação magnética vigorosa por 20 min, transcorrido o tempo foi realizado tratamento térmico em mufla a 500 ºC por 2h. As nanopartículas obtidas apresentaram característica cristalina e diâmetro médio de 32,24 nm. O espectro FTIR do extrato apresentou diversos picos relacionados a compostos redutores capazes de realizar a síntese, enquanto o espectro das nanopartículas demonstrou que mesmo após a calcinação, ainda se detecta a presença de compostos orgânicos que podem ser responsáveis pela estabilização das mesmas. Sendo assim, o extrato etanólico de E. dunnii possui capacidade redutora para realizar a síntese de nanopartículas cristalinas de óxido de zinco. Palavras-chave: eucalipto, ZnO, biossíntese, Eucalyptus dunnii

Hydrothermal treatments to promote surface inactivation and increased flexibility in three hardwoods

In the present study, three juvenile hardwoods (namely sycamore, pecan and london plane) were treated by boiling, steaming and microwave. Trees from Platanus x acerifolia (sycamore), Carya illinoinensis (pecan) and Luehea divaricata (london plane) were selected in homogeneous forests located in southern Brazil. Each hydrothermal treatment was performed for 60 min. In general, the hydrothermal treatments caused a certain surface inactivation effect, which was marked by decreased surface roughness, increased hydrophobic character and darkened colour patterns. Also, both decreased stiffness and strength, as well as increased deflectibility were obtained. These mechanisms were attributed to degradation in fine segments from amorphous polysaccharides, leaching of some organic extractives and fragmentation of lignin, as indirectly indicated by infrared spectra

EFICIÊNCIA DE PRESERVANTES FUNGICIDAS EM MADEIRAS DE DUAS ESPÉCIES FLORESTAIS SUBMETIDAS À DETERIORAÇÃO POR FUNGO

O objetivo desse estudo foi avaliar a eficiência de produtos fungicidas na preservação de madeiras de Eucalyptus dunnii e Pinus elliottii. Para isso, corpos de prova de 2,5 x 2,5 x 0,9cm (tangencial x radial x longitudinal), foram impregnados com borato de cobre cromatado (CCB), piretróides sintéticos e carbamatos (PSC) e quelato de cobre e carbamatos (QCC), com concentrações de 2%, 4% e 6% por processo de vácuo-pressão. Avaliou-se a perda de massa e variação na dureza Janka e teor de umidade devido deterioração provocada pelo fungo de podridão branca Ganoderma applanatum. A perda de massa foi de 4,6% para o Eucalyptus dunnii e 11,9% para o Pinus elliottii. A deterioração elevou o teor de umidade e reduziu a dureza. Para ambas as espécies, observou-se correlação alta, diretamente proporcional e significativa para a perda de massa e teor de umidade. Já a relação entre a perda de massa e a dureza foi inversamente proporcional para ambas as espécies, sendo alta e significativa para o Eucalyptus dunnii, e não significativa para o Pinus elliottii. Concluiu-se que o princípio ativo de destaque frente aos demais foi o PSC, com concentração de 6% e que a perda de massa influenciou as outras propriedades.Palavras-chave: podridão branca, preservação da madeira, propriedades tecnológicas.EFFICIENCY OF PRESERVATIVES FUNGICIDES IN TWO FOREST WOODS SPECIES SUBMITTED TO FUNGUS DETERIORATION ABSTRACTThe objective of this study was to evaluate the efficiency of fungicide products in the Eucalyptus dunnii and Pinus elliottii wood preservation. For this, 2.5 x 2.5 x 0.9 cm (tangential x radial x longitudinal) specimens were impregnated with chromated copper borate (CCB), synthetic pyrethroids and carbamates (PSC), and copper chelate and carbamates(QCC) at concentrations of 2%, 4% and 6%, by vacuum-pressure process. It was evaluated the mass loss, and variation in Janka hardness and moisture content because the deterioration caused by the white rot fungus Ganoderma applanatum. The mass loss was 4.6% for Eucalyptus dunnii and 11.9% for Pinus elliottii. The deterioration increased the moisture content and reduced the hardness. For both species, a high and directly proportional and significant correlation was observed for mass loss and moisture content. However, the relationship between mass loss and hardness was inversely proportional to both species, being high and significant for Eucalyptus dunnii, and not significant for Pinus elliottii. It was concluded that the main active principle in relation to the others was the PSC, with concentration of 6% and that the mass loss influenced the other properties.Keywords: white rot, wood preservation, technological properties. DOI: http://dx.doi.org/10.5935/2318-7670.v05n06a0

Análise comparativa das propriedades físicas e mecânicas da madeira de três coníferas de florestas plantadas.

Woods from plantation stands of parana, slash and loblolly pines, thinned at least once, were tested with the objective of comparing physical and mechanical properties. Five threes from each specie were harvested from selected stands. The stems were bucked into logs and then transported to the sawmill cooperating in this study. The logs were processed into planks, which were air seasoned, and then cut into pieces according to ASTM standards. Although the average strength of parana pine was slightly larger than the two other pines, significant differences were found only in the tests of static bending (modulus of elasticity and tension at the proportional limit), compression parallel to the grain (maximum crushing strength, modulus of elasticity and tension at the proportional limit) and hardness (cross-section). The  properties  were  not  different  for  slash  and loblolly pines, except in tension perpendicular to the grain, where the strength of loblolly pine was higher than the others. No differences were found for specific gravity and shrinkage among the species.Madeiras provenientes de florestas plantadas de Araucaria angustifolia, Pinus elliottii e Pinus taeda submetidas a, pelo menos, um desbaste, foram testadas com o objetivo de comparar suas propriedades físicas e mecânicas. Cinco árvores de cada espécie, obtidas de talhões, previamente, selecionados, foram coletadas, transformadas em toretes e pranchões para posterior confecção, condicionamento e ensaio dos corpos de prova segundo as recomendações da norma ASTM. Embora a resistência média da Araucaria tenha sido ligeiramente superior às duas espécies de Pinus, diferenças significativas foram encontradas apenas nos testes de flexão estática (módulo de elasticidade e tensão no limite proporcional), compressão axial (tensão no limite proporcional, módulo de ruptura e de elasticidade) e dureza axial. Entre as espécies de Pinus, não foram dectadas diferenças nas propriedades, exceto em tração normal às fibras em que a resistência da madeira de P. taeda foi maior que as demais. Com relação à massa específica básica e coeficiente de contração, nenhuma diferença significante foi observada entre as espécies estudadas

Zinc oxide nanoparticles from microwave-assisted solvothermal process : photocatalytic performance and use for wood protection against xylophagous fungus

Nano- and micro-oxides are promising materials due to several interesting characteristics such as photocatalytic and antimicrobial role. In this work, zinc oxide nanorods were obtained by microwave-assisted solvothermal process and their photocatalytic performance and action for wood protection against wood-decay fungus was studied. The morphological (scanning electron microscopy and transmission electron microscopy analyses), microstructural (X-ray powder diffraction analysis) and chemical (infrared spectroscopy) characteristics of the oxide-based nanostructures were investigated. Moreover, photocatalytic performance was evaluated using methylene blue and methyl orange. The nanostructured zinc oxide was impregnated to pinewood samples at 1–5% content and tested for decay resistance using a white-rot fungus. Zinc oxide nanorods agglomerated as urchin-like structures presented high crystallinity, high purity, and high photocatalytic activity. Zinc oxide impregnation was effective in improving pinewood decay resistance, yielding similar protection compared to traditional wood preservative

Fourier transform infrared spectroscopy in treated woods deteriorated by a white rot fungus

This study aimed to analyze chemical changes by Fourier Transform Infrared Spectroscopy of Eucalyptus dunnii and Pinus elliottii treated woods subjected to an accelerated decay test with the white rot fungus Ganoderma applanatum. The wood test specimens (2,5x2,5x0,9 cm) were impregnated with preservative solutions of chromated copper borate and synthetic pyrethroids and carbamates with 6% concentration by a vaccum-pressure process. After a decay test of 16 weeks, the chemical changes of the treated and untreated wood samples were evaluated by Fourier Transform Infrared Spectroscopy. It was observed that the rot fungus attack caused a variation in the intensity and a displacement of spectrum peaks, indicating a change to the woods’ chemical composition after fungal exposure. The lignin / carbohydrate ratio indicated that the fungus had no preference for a specific cell wall component, pointing to a simultaneous deterioration of cellulose, hemicellulose and lignin in the treated and untreated woods. Finally, the Fourier Transform Infrared Spectroscopy technique, together with the lignin / carbohydrate ratio analysis, proved efficient in the study of the variation of the wood chemical modifications deteriorated by rot fungi

PRODUÇÃO MADEIREIRA NA REGIÃO DA QUARTA COLÔNIA DE IMIGRAÇÃO ITALIANA DO RIO GRANDE DO SUL

Este estudo foi conduzido com o objetivo de quantificar a produção madeireira na região da Quarta Colônia de Imigração Italiana do Rio Grande do Sul. Primeiramente, por meio de um questionário fez-se um censo das empresas consumidoras de madeira da região, inventariou-se, sobretudo, a quantidade, tipo, procedência da matéria-prima consumida, e a quantidade, tipo e destino da produção madeireira. Como principais resultados, verificou-se que a região da Quarta Colônia apresenta 77 empresas consumidoras e transformadoras de madeira. Estas foram classificadas em micro e pequenas empresas, com características e capital familiar, com baixa industrialização. Nas visitas feitas às indústrias, ficou evidente que muitos aspectos tecnológicos não são conhecidos ou são negligenciados, resultando em mau aproveitamento da matéria-prima e/ou na baixa qualidade dos produtos finais. Constatou-se que uma grande quantidade de matéria-prima (96,8% das tábuas e 98,9% das pranchas) provêm de outras regiões do Estado ou do País. Da mesma forma, os principais produtos são vendidos para fora da região (esquadrias 86,3%, lambris 99,7% e madeira serrada 53%)