Progress Update on Bonding E-glass to Wood Using a Modified Polyester Resin
Publication Name: Proceedings of the 2nd International Conference on Advanced Engineered Wood Composites
This paper discusses the use of modified isophthalic acid unsaturated polyesters in the bonding of wood to E- glass fibers in the production of engineered wood composites. Previous efforts have shown standard unsaturated polyester resins have low compression shear strengths using ASTM D 905. Samples were generated and tested for compression shear strength (two groups were done in both a dry and a “wet” test), and ASTM D 1101 for cycle delamination. Samples labeled ÒwetÓ under D 905 were put through the exact vacuum-pressure cycle used in D 1101 testing. The wood substrate used was hard maple. Hydroxymethylated resorcinol (HMR) coupling agent was also shown to increase the adhesive bonding and decreases delamination. The uniaxial E- glass (4 layers) were hand impregnated. The amount of resin used for each layer was equivalent to the weight of the fiberglass at that layer, in an attempt to achieve a 50% fiber weight fraction in the FRP. The shear strengths of the modified polyester resins were ~8.3-22.8 MPa dry test and ~8.2-9.0 MPa wet test. In comparison, the shear strengths achieved in earlier research with standard unsaturated polyesters were ~ 6.9 – 16.6 MPa (dry testing only) and those products failed after one cycle in the cycle delamination test.