Dynamic Mechanical Analysis: A Novel Method to Screen Potential Wood Adhesion Promoters

摘要

ilute alkaline solutions of hydroxymethyl resorci-nol (HMR) are effective adhesion promoters (primers) for wood bonding; HMR dramatically increases durability against moisture exposure. Recent studies in our group demonstrated that HMR causes an increase in the glass transition (T_g) of lignin, the amorphous wood polymer that binds cellulose fibrils together. This analysis involves dynamic torsion while the wood specimen is immersed in dimethylformamide. This solvent submersion dynamic mechanical analysis (DMA) simplifies observation of the lignin T_(g') which in dry wood is accompanied by thermal degradation of the sample. HMR's effect on the lignin T_g suggests that careful observation of this transition might provide a simpler method of screening chemical treatments as possible wood adhesion primers. Currently, wood primers are evaluated with a very laborious ASTM method (D2559). Consequently, the objective of this work is to improve the technique of submersion torsion wood DMA, and to determine if such DMA is effective for predicting the priming potential of other chemical treatments. In order to validate DMA results, Mode I fracture testing was conducted in order to investigate the bond toughness as a result of chemical treatment.