Effects of Selected Wood Species and Moisture Content on PMDI Resin Application and Panel Properties
Keywords:pMDI, aspen, poplar, pine, composites, resin droplet size, internal bond strength, thickness swell
AbstractThis study investigated the effect of selected species and moisture conditions on resin distribution and composite panel properties. Flakeboard composites were made from aspen, pine, or poplar flakes that were equilibrated to 4, 8, or 12% moisture content (MC). Resin droplet size (resin "footprint") was measured, as was the percentage of the flake surface that was covered by resin. Aspen flakes showed higher resin coverage and also larger resin droplet sizes. Conversely, pine and poplar flakes had smaller resin droplets and lower resin coverage per flake surface, suggesting greater pMDI penetration. Internal bond (IB) testing revealed optimal performance for aspen flakes at 12% precure MC, and poplar and pine flakes at 8% precure MC. Modulus of rupture and modulus of elasticity results correlated with IB results. Aspen panels bonded at 8 and 12% MC had minimal thickness swell.
ASTM (2006) Method D 1037-06a. American Society for Testing and Materials.nBao S, Daunch WA, Sun Y, Rinaldi PL, Marcinko JJ, Phanopoulos C (2003) Solid state two-dimensional NMR studies of polymeric diphenylmethane diisocyanate (PMDI) reaction in wood. Forest Prod J 53(6):63-71.nDas S, Malmberg MJ, Frazier CE (2007) Cure chemistry of wood/polymeric isocyanate (PMDI) bonds: Effect of wood species. Int J Adhes Adhes 27(3):250-257.nFrazier CE (2003) Isocyanate wood binders. Pages 681-694 in A. Pizzi and K. L. Mittal, eds. Handbook of adhesive technology. Marcel Dekker, New York, NY.nGruver TM, Brown NR (2006) Penetration and performance of isocyanate wood binders on selected wood species. BioRes 1(2):233-247.nJohns WE, Maloney TM, Saunders JB, Huffaker EM, Lentz MT (1982) The effect of species and moisture content on the bonding efficiency of polymeric MDI isocyanate Proceedings of the 16th Washington State University International Particleboard Symposium. Pullman, WA, 71-98.nJohns WE, Rammon RM, Youngquist J (1985) "Chemical effects of mixed hardwood furnish on panel properties" Proceedings of the 19th Washington State University particleboard/composites material series symposium. Pullman, WA, 363-377.nKamke FA, Lenth CA, Saunders HG (1996) Measurement of resin and wax distribution on wood flakes. Forest Prod J 46(6):63-68.nMarcinko JJ, Devathala S, Rinaldi PL, Bao S (1999) Investigating the molecular and bulk dynamics of PMDI/wood and UF/wood composites. Forest Prod J 48(6):81-84.nMarcinko JJ, Rinaldi PL, Bao S (1998) Exploring the physicochemical nature of PMDI/wood structural composite adhesion. Forest Prod J 49(5):75-78.nPapadopoulos AN, Hill CAS, Traboulay E, and Hague JRB (2002) Isocyanate resins for particleboard: PMDI vs. EMDI. Holz Roh-Werkst 60:81-83.nSmith GD (2003) The lap-shear strength of droplets arrays of a PF-resin on OSB strands. Forest Prod J 53(11-12): 67-73.nZhou X, Frazier CE (2001) Double labeled isocyanate resins for the solid-state NMR detection of urethane linkages to wood. Int J Adhes 21:259-264.n
The copyright of an article published in Wood and Fiber Science is transferred to the Society of Wood Science and Technology (for U. S. Government employees: to the extent transferable), effective if and when the article is accepted for publication. This transfer grants the Society of Wood Science and Technology permission to republish all or any part of the article in any form, e.g., reprints for sale, microfiche, proceedings, etc. However, the authors reserve the following as set forth in the Copyright Law:
1. All proprietary rights other than copyright, such as patent rights.
2. The right to grant or refuse permission to third parties to republish all or part of the article or translations thereof. In the case of whole articles, such third parties must obtain Society of Wood Science and Technology written permission as well. However, the Society may grant rights with respect to Journal issues as a whole.
3. The right to use all or part of this article in future works of their own, such as lectures, press releases, reviews, text books, or reprint books.