Review on biocides nanoparticles. Nanoparticles-based wood preservatives. Nanoparticles biocides applied on wood protection. Protection against biodeterioration through nanotechnology.

The glued laminated timber (glulam) is a composite material obtained from the bonding of wood laminae arranged with parallel fibers put together. The purpose of this paper was to evaluate the influence of the number of laminae on the mechanical behavior of glulam of Toona ciliata produced with vegetable-based polyurethane adhesive. The glulam beams were produced with lamellae in the dimensions of 6.0 x 1.5 x 120.0 cm, with 3 beams being made per treatment, which were structurally composed by 5, 7 and 9 laminae. The polyurethane adhesive based on castor oil was used, applying a grammage of 350 g m-². For the technological characterization of the wood the moisture in the dry base, bulk density, chemical characterization, compressive strength parallel to the fibers, shear and modulus of elasticity (MOE) and rupture (MOR) in the static bending test. While the properties of modulus of elasticity (MOE), modulus of rupture (MOR), shear strength, delamination and visualization of the glue line through photomicrographs of the laminated wood samples were determined for glulam beams. The results showed that the beams with 5 laminae presented values similar to solid wood. The increase in the number of laminae provided lower values for stiffness and strength of the beams. The photomicrographs showed the quality of the bonding and the satisfactory values for shear strength and delamination, indicating the viability of the species under study for situations with high moisture content.

A demanda por produtos a base de madeira é crescente, principalmente a partir de florestas plantadas.  Dessa forma é possível maximizar o aproveitamento da madeira e obter produtos com resistência e confiabilidade de utilização. Objetivou-se estudar as propriedades tecnológicas d compensado e do LVL (Laminated Veneer Lumber) produzidos com madeira de paricá (Schizolobium amazonicum Huber ex Ducke). Avaliou-se a absorção de água, densidade (básica e aparente), umidade, porosidade, inchamento em espessura e inchamento residual. Utilizou-se 30 corpos de prova de cada tipo de painel, os dados foram analisados por meio de estatística descritiva e pela matriz de correlação de Pearson. No compensado a densidade básica, densidade aparente e porosidade foram de 0,38 g cm-3, 0,44 g cm-3 e 75,47%, respetivamente. Ainda, a umidade elevou-se 20,91% entre 2 e 96 horas de imersão em água. O inchamento residual foi de 3,75% e o inchamento em espessura aumentou 0,81% entre 2 e 96 horas de imersão. No LVL, a densidade básica (0,41 g cm-3) e a densidade aparente (0,48 g cm-3) foram maiores em relação ao compensado e a porosidade foi menor. O inchamento residual (4,24%) e o aumento em inchamento em espessura (1,22%) foram maiores em relação ao compensado. Por apresentarem alta higroscopicidade, as aplicações dos painéis avaliados devem ser preferencialmente em ambientes sem contato com umidade.

This work aimed to evaluate the physical and mechanical behavior of glued laminated timber (GLT) - glulam pieces of Hevea brasiliensis treated with chromed copper arsenate (CCA), chromed copper borate (CCB) and pyrethroid in the production of GLT. The pieces were produced using three wooden laminae with dimensions of 60 x 20 x 1200 mm, (width x thickness x length), joined with epoxy adhesive under 1.0 MPa pressure for 24h at room temperature. The rubberwood had an apparent density of 0.624 g cm-3, a value close to that of Eucalyptus grandis wood, a species traditionally used in the manufacture of GLT. Regarding the GLT parts, it was observed that the preservative treatment with CCA and CCB influenced negatively the values of the mechanical properties. For resistance modulus (MOR), a reduction of 75.44 MPa to 62.36 and 58.57 MPa was found for the parts untreated and treated with CCA and CCB, respectively. There was no statistical difference for surface treatment with pyrethroid. The photomicrographs of the glue line showed that the reduction in these values was mainly due to the penetration of preservative solutions into the wood structure (cell lumens and vessels or pores), impairing the anchoring of the adhesive.

The accumulation of petroleum polymers compromises biodiversity and causes environmental problems. Nanocellulose enhances biodegradability and can improve the physical-mechanical performance of materials. The objective was to produce and characterize hybrid films composed of bacterial cellulose (BC) and plant nanocellulose from Eucalyptus (Euc) or Pinus (Pin). Films were produced by the casting method using filmogenic suspensions with different cellulose nanofibrils (CNFs) proportions from both the sources (0, 25, 50, 75 and 100 %). CNFs suspensions were characterized by transmission electron microscopy. The morphology of the films was analyzed using scanning electron microscopy. In addition, the transparency, contact angle, wettability, oil and water vapor barrier and mechanical properties were also evaluated. The contact angles were smaller for films with BC and the wettability was greater when comparing BC with plant CNFs (0.10 °  s − 1 {\text{s}^{-1}} for 75 % Euc/25 % BC and 0.20 °  s − 1 {\text{s}^{-1}} for 25 % Euc/75 % BC). The water vapor permeability (WVP) of the 100 % BC films and the 25 % Euc/75 % BC composition were the highest among the studied compositions. Tensile strength, Young’s modulus and puncture strength decreased considerably with the addition of BC in the films. More studies regarding pre-treatments to purify BC are needed to improve the mechanical properties of the films.