Static bending of glulam beams manufactured with rubber wood and epoxy adhesive

The aim of this study was to evaluate the properties of Hevea brasiliensis wood wastes for production structural pieces of glued laminated (glulam) timber. Three trees with age close to 25 years and diameter at breast height (DBH) higher than 500 mm were obtained. The basic density of the wood were quantified, as well as the stiffness and the strength in static bending, shear strength and parallel compression to grain and hygroscopic equilibrium moisture. The beams of glulam were evaluated according to the modulus of elasticity (MOE), modulus of rupture (MOR) and delamination. Due to the bending properties MOR (75.14 MPa) and MOE (8166.79 MPa), as well as the shear strength (12.29 MPa) obtained, was concluded by the suitability of the rubber wood for the production of glulam beams. The composite beams presented values of MOR (75.14 MPa) and MOE (8166.79 MPa) compatible with species traditionally used in the production of glulam beams. The adhesive bond quality was verified by the delamination test, presenting delamination of 4.95 %, indicating its use for internal and external environments.Keywords: Composite; Wood; Bond resistance; Static bending

Use of maize cob for production of particleboard

Agricultural residues are materials generated in large quantities in Brazil and can accumulate to such extent as to cause environmental problems. Among agricultural residues, maize cob is one worthy of notice, and an alternative use for maize cob would be to produce particleboard panels in association with wood particles. This study aimed to evaluate the feasibility of using maize cob for production of particleboard panels. The following maize cob percentages were used: 0%, 25%, 50%, 75% and 100%, in association with particles of Pinus oocarpa wood. Panels were made with 8% of urea formaldehyde and 1% of paraffin (based on dry weight of particles). For compressing the panels, a pressure of 3.92 MPa was applied at a temperature of 160º C, for 8 minutes. Increased replacement of pinewood by maize cob residue promoted significant improvements to the properties water absorption after two hours of immersion, thickness swelling after two and after twenty-four hours of immersion. Mechanical properties had a decreasing correlation with the maize cob percentage being incorporated

THERMAL STABILITY OF Pinus oocarpa AND MAIZE COB PARTICLEBOARDS

Agricultural waste materials are generated in large quantities in Brazil. These can accumulate and cause serious environmental problems. One of the most commonly generated wastes in the brazilian agricultural culture is the maize cob. Being lignocellulosic in nature, the maize cob can find use as the raw material in the production of particleboards mainly concerned with furniture making. Therefore, studies regarding its thermal stability and fire resistance would be interesting. The aim of this study was to evaluate the combustibility and thermal stability of the particleboards produced from maize cob and Pinus oocarpa wood. The percentages in which maize cob was associated with Pinus oocarpa were 0%, 25%, 50%, 75% and 100%. The panels were produced using 8% urea-formaldehyde and 1% paraffin. The pressing cycle parameters included: temperature 150 °C, pressure of 3.92 MPa during 10 min. The combustibility curve analysis showed that the panels containing 25% content of maize cob had higher resistance to combustion. In general, the thermal stability decreased as the wood substitution by maize cob increased

Relation of transverse air permeability with physical properties in different compositions of sugarcane bagasse particleboards

Studies concerning the production of particleboards with sugarcane bagasse as an alternative fibrous material have been carried out as an attempt to provide a sustainable and viable destination for this residue. This work aimed to evaluate the influence of several processing variables related to the microstructure of sugarcane bagasse particleboards (mat type, adhesive type and adhesive content) on their permeability and water sorption properties. Air permeability data was collected by the rotameter method. Superficial air permeability (kg), Darcian constant (k1) and non-Darcian constant (k2) were measured. kg was related to sorption behavior of the particleboards. 1-layer particleboards presented significantly higher kg values than the 3-layer particleboards. In general, adhesive type, position and content did not influence kg of particleboards. However, these processing variables influenced interactions between fluid and material and tortuosity of the porous media. Particleboards produced with urea-formaldehyde with high kg presented higher water absorption and thickness swelling after 24 hours. Such relations were not observed in particleboards produced with melamine-urea-formaldehyde

Eucalyptus wood and coffee parchment for particleboard production: Physical and mechanical properties

ABSTRACT The wood panel industry is constantly growing, being necessary the innovation in technologies and raw materials to improve the quality of the final product. Considering the shortage and pressure to decrease the dependence of wood, there is an interest in other renewable materials such as agricultural wastes. Among these wastes, coffee parchment is one which deserves notoriety. An alternative use for coffee parchment could be for production of particleboard in association with wood particles. This study aimed to evaluate the feasibility of using coffee parchment for production of particleboard. The following percentages of wastes were used: 0, 10, 20, 30, 40 and 50% in association to eucalyptus wood. The panels were produced with 8% of urea formaldehyde (based on dry weight of particles). The pressing cycle consisted by: pre-pressing of 0.5 MPa for 10 minutes followed by pressing of 4.0 MPa, and temperature of 160° C for 15 minutes. The compaction ratio of particleboards produced using higher quantities of parchment improved the physical properties. The properties of Water Absorption (2 and 24 h) and Thickness Swelling (2 h) decreased with increasing percentage of coffee parchment. The Thickness Swelling (24 h) showed not significant effect with an increase of coffee waste. The Modulus of Elasticity for coffee parchment particleboards was in the range 646.49 ± 112.65 to 402.03 ± 66.24 MPa, while the Modulus of Rupture ranged from 8.18 ± 1.39 to 4.45 ± 0.75 MPa. The results showed that 10% of coffee parchment could be added for production of particleboards

Performance of glulam beams produced with free-formaldehyde adhesive and underexploited rubber wood treated with preservatives solutions of chromated copper borate and pyrethroids

The release of formaldehyde may cause serious human health problems. Free-formaldehyde adhesives is increasingly well regarded by industry, since some adhesives are effective in providing of good mechanical properties even when the object of study is treated wood. This study proposes to evaluate the properties of rubber wood treated with chromated copper borate (CCB) and pyrethroid to produce glued laminated (glulam) timber using different types of adhesives as a binder. The modulus of elasticity (MOE) of the rubber wood pieces was investigated and predicted in this study before the glulam beams production. Glulam beams were glued with: polyurethane (as a free-formaldehyde adhesive) and resorcinol–formaldehyde, in the presence or absence of preservative treatment. Each beam was composed by three wood pieces. In total, 30 glulam beams were produced, 15 for each type of adhesive (60 mm thickness, 60 mm wide and 1200 mm length). Rubber wood treated with CCB showed a significant increase in pH. The glulam beams with polyurethane did not present statistical difference from those produced with resorcinol–formaldehyde for MOE and MOR. The MOE values of the beams glued with polyurethane were 6124.66 and 5768.93 MPa for the treatment with CCB and pyrethroid, respectively. The glulam beams samples showed the same efficiency in shear strength test for both adhesives. The results indicate that polyurethane adhesive could be used as a possible alternative for glulam beams productio

Particleboard Panels Produced with Different Radial Positions of Pinus oocarpa Wood

<div><p>ABSTRACT The aim of this study was to evaluate the effect of different radial regions of Pinus oocarpa wood on the physical and mechanical properties of particleboard panels. Three different radial regions (internal, intermediate and external) and the mixture (integral log) were assessed. Experimental panels were produced with a nominal density of 0.70 g/cm3 using 8% urea-formaldehyde adhesive; they were compressed at a specific pressure of 40 kgf/cm2 and temperature of 160 °C, for 8 minutes. Wood radial position affected particleboard quality and a direct influence of the chemical composition and density of the material used was observed. Only the panels produced the mixture (integral log) and with the internal region met all the requirements stipulated by the marketing standard.</p></div