2003 Progress Report: Fundamental Studies of Wood Interface Modification for Formaldehyde Pollution Avoidance and PreventionEPA Grant Number: R828565
Title: Fundamental Studies of Wood Interface Modification for Formaldehyde Pollution Avoidance and Prevention
Investigators: Meister, John J. , Choi, Gun Y.
Institution: University of New Mexico - Main Campus , Forest Products Research Center
Current Institution: Forest Products Research Center
EPA Project Officer: Hahn, Intaek
Project Period: September 15, 2000 through September 14, 2003
Project Period Covered by this Report: September 15, 2002 through September 14, 2003
Project Amount: $324,254
RFA: Technology for a Sustainable Environment (1999) RFA Text | Recipients Lists
Research Category: Sustainability , Pollution Prevention/Sustainable Development
The objective of this research project is to support fundamental studies of thermoplastics that tacify the wood interface to determine if lignin copolymer-plastic blends can act as a binder in wood laminates or composites. These plastics would replace formaldehyde-based adhesives, and would remove the source of the major domestic environmental exposure to formaldehyde.
Poly(lignin-g-[1-phenylethylene]) graft copolymer/poly(1-phenylethylene) is an effective plywood binder, which is four times more durable, equal in tensile strength, and equal in compression strength to interior grade, urea-formaldehyde (methanal diamine-methanal) binders. Three-ply, Douglas fir plywood was made with graft copolymer and pure polystyrene binders. The plywoods were tested for delamination and compared to a commercial, Douglas fir plywood. Laboratory-made plywood bound with 18 percent and 24 percent lignin content copolymer, poly(1-phenylethylene) (styrene control: no copolymer layer), was tested by soak test, tensile test, and compression test with commercial Douglas fir and maple plywood.
In the soak/dry test, the laboratory-made plywood bound with 18 percent lignin content copolymer and commercial Douglas fir showed a low delamination rate. The average tensile energy decreased as the cycles of soak/dry exposure increased. The commercial Douglas fir bound with phenol-formaldehyde showed a tensile energy twice that of the three-ply woods bound with other binders. The plywood bound with 18 percent lignin copolymer showed higher tensile energy than the 24 percent lignin copolymer binder. In compression test, the copolymer- bound samples are stronger than interior grade urea formaldehyde binder, commercial maple plywood, but weaker than phenol formaldehyde binder, commercial Douglas fir plywood.
Tests were run on both sanded and unsanded plys formed into plywood at different pressures, temperatures, and durations for pressing. Samples made with sanded ply were generally weaker and less durable than plywood formed from sanded ply. Plywoods formed at different pressing durations and pressures had equal physical properties. Changing the temperature of the plywood formation process from 150°C to 190°C changed the failure mode of the plywood. Samples formed at 190°C tended to fail in the wood under tensile force, but those formed at 150°C tended to undergo tensile failure in the bond. These renewable material-produced and recycled plastic- based binders exceed the performance of urea-formaldehyde binders in industry standard performance tests.
After 84 total cycles of soaking and drying, the plywood bound with 18 weight percent lignin copolymer and polystyrene showed less than one-fifth of the delamination of the polystyrene control, but 7 percent more delamination than the commercial, Douglas fir plywood. All of these samples outperformed commercial, urea formaldehyde-bound maple plywood.
We will optimize this binder and improve the application process to form the best wood composite (plywood) possible.
Journal Articles on this Report : 2 Displayed | Download in RIS Format
|Other project views:||All 27 publications||3 publications in selected types||All 2 journal articles|
||Adcock T, Shah V, Chen M-J, Meister JJ. Graft copolymers of lignin as hydrophobic agents for plastic (wood-filled) composites. Journal of Applied Polymer Science 2003;89(5):1266-1276.||
||Meister JJ. The modification of lignin. Journal of Macromolecular Science-Polymer Reviews 2002;C42(2):235-290.||