Effect of resin content on the water-resistant, mechanical, and thermal properties of scrimber made from radiata pine wood (Pinus radiata D. Don)

Scrimber is processed by laminating wood fiber mats impregnated with phenolic resin under hot pressing. One of its essential components is phenolic resin. In this study, the effect of phenolic resin content on the structural, water-resistant, mechanical, and thermal properties of pinewood scrimbers was investigated. Results showed that phenolic resin facilitated the collapse of cell walls at low pressure during lamination, and higher resin content markedly reduced cell wall cracking. The cellulose I structure of pinewood remained intact, whereas its crystallinity decreased as resin content increased. Moreover, the resin significantly improved water resistance and dimensional stability; an increase in resin content led to a more pronounced improvement. The water absorption in 35 h at a resin content of 15 wt.% was approximately 1/10 of that at 9 wt.%. Scrimbers with a resin content of 9 wt.% exhibited a 50% increase in modulus of rupture (MOR) and a more than 1.4-fold increase in modulus of elasticity (MOE) relative to that of solid pine wood. As the resin content increased, MOR remained stable, MOE slightly decreased, and shearing strength increased. In addition, phenolic resin promoted the thermal degradation of scrimbers, and the higher resin content in the scrimber led to better thermal degradation.