Adhesives have played and will continue to play an important role in the efficient utilization of wood resources. Early Egyptians used adhesives to attach rare veneers to wood furniture. Today, adhesives play a vital role in allowing almost all types and sizes of wood to be converted to functional products. For centuries, wood was bonded using biobased adhesives. In the 20th century, synthetic adhesives gradually took over because they were typically more effective and cost less. Refinement of these adhesives led to a great expansion in the bonded wood products industry by growing existing markets and allowing development of new

Abstract

Although it is well known that wood can absorb liquids, the full impact of this phenomenon on resulting adhesive cure and performance is not well understood. In a related soy adhesive study, aspects of this phenomenon were not fully anticipated and resulted in a significant impact on adhesive bond quality. In essence, the wood being bonded acted like chromatography media, filtering relatively smaller molecules from the surrounding adhesive matrix and altering the local composition of the adhesive material. Through the use of soy adhesives containing glycerin, the infiltration of glycerin analogs into wood cell walls has been determined and related with the impact on bondline and wood properties. The impacts of infiltration and chromatographic separation on the cured adhesive are also discussed.

Abstract

Urea-formaldehyde (UF) resin is the predominant adhesive used in the manufacture of medium-density fiberboard (MDF). While it is well known that this resin is susceptible to moisture and hydrolysis, the present study determined that MDF panels lose a significant quantity of UF resin components in panel water soaking tests. Panel mass and %N losses indicate that MDF panels lose 48 to 66 percent of resin components during water soaking tests. Chemical analysis revealed that the labile extractable resin components included urea and monomeric and low-molecular-weight UF oligomers. Panel formaldehyde emissions were linked to the proportions of extractable UF resin oligomers. The results have implications for panel performance and the extent of resin cure achievable in manufacturing MDF.

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 made with these resin systems can meet the PBU requirements in terms of IB and hardness and that those bonded with 8 percent PF or 5 percent pMDI can meet all the requirements by the ANSI A208.1‐2009 standard for the floor underlayment application in terms of the properties evaluated. Results of this study imply that it is feasible to use bark as a raw material to manufacture medium-density particleboard for the floor underlayment application.

Introduction to Special Issue: Wood Adhesives: Past, Present, and Future

Wood as Polar Size Exclusion Chromatography Media: Implications to Adhesive Performance *

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Labile Extractable Urea-Formaldehyde Resin Components from Medium-Density Fiberboard *

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

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Soy Flour Adhesive Strength Compared with That of Purified Soy Proteins *

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Effects of Ethanol-Supplemented Phenol-Resorcinol-Formaldehyde Resin on Formaldehyde and Acetaldehyde Emissions from Glued-Laminated Timbers *

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Development of Wood-Based Materials Bonded with Citric Acid *

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

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Methylene Malonates and Cyanoacrylates: Energy-Efficient, High-Performance Sustainable Adhesive Systems *

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Novel Analytical Method to Determine Factors Causing Unwanted Sticking of Glued Wood Particles onto Machinery Parts *

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Creep Testing of One-Component Polyurethane and Emulsion Polymer Isocyanate Adhesives for Structural Timber Bonding *

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Regional Drivers of Primary Wood Processing Mills in the Western Southeast US

Shear and Bending Properties of Homogeneous and Hybrid CLT Panels Fabricated from Low-Value North American Hardwood Species

Impact of Market Price Fluctuations on the Break-Even Log in Hardwood Sawmills

Tourists’ Pro-Environmental Behavior in Forest-Based Tourism through Multi-Methods Analysis

Effect of Decoration Complexity and Age on Aesthetic Evaluation, Purchase Intention, and Visual Attention in Wood Furniture

Moisture Content, Specific Gravity, and Percent Foliage Weight of Cottonwood Biomass

Using Life-Cycle Assessments to Demonstrate the Impact of Using Wood Waste as a Renewable Fuel in Urban Settings for District Heating

Decay Hazard (Scheffer) Index Values in Korea for Exterior Aboveground Wood

Effect of Setting during Construction on Properties of Douglas-Fir Plywood and Oriented Strandboard Flooring

Study on Urea-Formaldehyde Prepolymer and Hot-Press Treatment of Italian Poplar Wood