Resistência ao cisalhamento na linha de cola em juntas de parapará (Jacaranda copaia) e ipê (Handroanthus sp.)

Abstract

Wood is an indispensable raw material for applications in civil construction, the furniture industry, the pulp and paper industry, among others. In its massive form and in larger dimensions, wood has become, over the years, a difficult material to find due to the constant reduction of native forests and the current environmental legislation. Thus, the sectors that use it have sought new alternatives for a more rational use, in this sense wood adhesive plays an increasingly important role in the forestry products industry and this possibility of use makes management in the Brazilian Amazon forest more sustainable. The main objective of the present study was to evaluate the resistance performance of different adhesives used for bonding two species of Amazonian tropical woods. Woods from Parapará (Jacaranda copaia) and Ipê (Handroanthus sp.) were used. The specimens were made according to the ASTM D 905-08 standard. For the shear test on the glue line, specimens were made for each species and adhesive. These were sanded and the joints bonded with three industrial adhesives based on polyurethane (PU), isocyanate (EPI), and polyvinyl acetate (PVAc). The shear strength values of the glue line in Handroanthus sp. were significantly higher than in Jacaranda copaia joints in all evaluated adhesives. The wood of Handroanthus sp. glued with PU and PVAc showed the highest values of shear strength with efficiency above 90% in the glue line. For Jacaranda copaia wood, bonding with PU adhesive only is recommended due to efficiency above 90% and a higher shear resistance value.