Investigation of Decay Resistance of Alkaline Copper, Urea-Formaldehyde, and Phenol -Formaldehyde Resins

The decay resistance of modified fast-growing poplar lumber with ion-based preservative and thermosetting resins were determined in laboratory and field stake tests. Commercial alkaline copper quat-type D (ACQ-D), thermosetting phenol–formaldehyde (PF) resin with varying concentrations, and urea–formaldehyde (UF) resin were used to improve decay resistance of low-grade fastgrowing poplar. The results indicated that the concentrations of PF and weight gains of resin-modified specimens were highly correlated, and target resin retains can be achieved from resin concentration. The retention rates of ACQ of 1.1% concentration, UF of 41.5% concentration and PF of 10% concentration were 6.72, 18.43, and 7.31 kg/m3, respectively. For PF, the retention rate is linearly related to concentration. The mass losses (ML) for the untreated, ACQ-treated, and UF-treated specimens were 26.34%, 8.91%, and 11.66% after 12 wk of incubation in laboratory, respectively. The ML for the treated specimens were 9.74%, 7.32%, 3.14%, 2.38%, and 2.41% for PF impregnated wood at concentrations of 10%, 15%, 20%, 25%, and 40%, respectively, after 12 wk of incubation in the laboratory.