Martin Feng

Bark extractives-based phenol–formaldehyde resins from beetle-infested lodgepole pine

In this study, phenol–formaldehyde (PF) resins derived from the bark extractives were synthesized and characterized. Bark of lodgepole pine (Pinus contorta Dougl.) infested by mountain pine beetle (Dendroctonus ponderosae Hopkins) was first extracted with 1% NaOH. The bark extractives with and without acid-neutralization were then dried to the solid state. The neutralized and non-neutralized extractives were used to partially replace petroleum-based phenol for synthesizing the bark extractives-PF resins. In comparison with a commercial PF resin and a laboratory made PF resin (Lab PF), the bark extractive-PF resins were found to have higher molecular weights, higher viscosities, and shorter gel times. Acid neutralization of the bark extractives increased the molecular weight of the extractives and modified the performance and curing behavior of the resulting bark extractive-PF resins. Bark extractive-PF resins (BEPF) showed a similar level of post-cured thermal stability to that of the lab PF at higher temperatures, but they differed significantly from that of the commercial PF resin. The bark extractive-PF resins made from both neutralized and non-neutralized extractives at 30% replacement of phenol (by weight) exhibited similar dry and wet bond strengths to the commercial PF resin. At 50% substitution level, BEPF had dry and wet bond strengths similar to the lab PF resin. Our findings suggest that alkaline extractives from mountain pine beetle-infested lodgepole pine bark are suitable for partially substituting phenol in the synthesis of phenolic resin for use in wood adhesives.

Effects of Pressing Temperature and Particle Size on Bark Board Properties Made from Beetle-Infested Lodgepole Pine (Pinus contorta) Barks

Mountain pine beetle (Dendroctonus ponderosae)–infested lodgepole pine (Pinus contorta) bark was used to make particleboard panels (bark board) without synthetic resins. The effects of pressing temperature and particle size on the mechanical properties of the bark boards were examined. The study revealed that pressing temperature and particle size have great influence on mechanical, physical, and hygroscopic properties of self-bonded bark boards. Higher pressing temperatures resulted in improvements in all properties studied, including increases of modulus of elasticity and modulus of rupture by approximately 4 times and an increase of internal bond strength by nearly 10 times when comparing boards pressed at 170°C versus 230°C. Boards produced from fine bark particles showed better mechanical performance than boards produced from coarser bark particles except for internal bond strength, which was highest in boards containing bark particles of mixed sizes. Scanning electron microscopic images of fractured...

Fungus-Modified Lignin and Its Use in Wood Adhesive for Manufacturing Wood Composites*

Abstract Organosolv lignins were modified with different fungal species. The modified lignins were used as raw materials for preparing lignin-phenol-formaldehyde (LPF) resins. Oriented strandboard ...

Synthesis and Characterization of Bio-Based Phenol-Formaldehyde Resol Resins from Bark Autoclave Extractives

Abstract With the growing concern for fossil fuel depletion and environmental carbon footprint, there is a strong interest in exploring the renewable biomass materials as substitutes for petroleum-...

Correlation of Adhesive Performance between Automated Bond Evaluation System Tests and Plywood Tests - A Case Study of Lignin-PF Adhesives

Abstract The automated bond evaluation system (ABES), which recently became ASTM D7998-15 standard test method, is an effective tool for screen testing of different water-based wood adhesive formul...

Manufacturing Medium-Density Particleboards from Wood–Bark Mixture and Different Adhesive Systems*

Abstract The disposal problem of bark residues and the shortage of wood raw material supply in some regions make the use of bark an attractive option for the industry. In this study, medium-density particleboards were manufactured from mixed black spruce bark and spruce-pine-fir wood particles at a weight ratio of 50/50. Different adhesive systems were used as binders for the bark-based panels, including commercial phenol-formaldehyde (PF), urea-formaldehyde (UF), polymeric methylene diphenyl diisocyanate (pMDI) resins, and a laboratory-synthesized lignin-PF resin containing 30 wt% lignin substitution for phenol. The objective was to investigate the suitability of utilizing bark residues in the manufacture of particleboards for the floor underlayment (PBU) application. The resulting boards were evaluated according to the ANSI A208.1‐2009 standard for internal bond (IB), modulus of rupture, modulus of elasticity, hardness, thickness swell, and linear expansion. The test results indicate that all panels mad...