Fungal decay resistance and mechanical properties of plywood panels made from maritime pine (Pinus pinaster) and bonded with cornstarch-quebracho tannin-phenol formaldehyde adhesive
F Charrier, A Moubarik, A Allal, A Pizzi, B Charrier
The aim of this work is to demonstrate the performances of cornstarch-quebracho tannin-based resins designed as adhesive in the plywood production. In this way, the cornstarch and quebracho tannin was introduced in the classic adhesive formulation in order to supply a part of phenol-formaldehyde (PF). In order to evaluate the mechanical performances of optimal cornstarch-quebracho tannin-PF, plywood panels were produced and mechanical properties were investigated. These mechanical properties included tensile strength, wood failure and 3-point bending strength. The biological performance of plywood panels against both Coriolus versicolor and Coniophora puteana rot fungi were evaluated. The performance of these panels is comparable to those of plywood panels commercial PF made. The results showed that plywood panels bonded with cornstarch-quebracho tannin-PF resins (15:5:80, w:w:w) exhibited better mechanical properties than plywood panels commercial PF made. The formaldehyde emission levels obtained from panels bonded with cornstarch-quebracho tannin-PF were lower to those obtained from panels bonded with control PF. Biodegradation studies show that the presence of quebracho tannin in the adhesive improves the
total resistance of the plywood panels against both Coriolus versicolor and Coniophora puteana rot fungi.