Treesearch

Plant-biomass-based nanomaterials have attracted great interest recently for their potential to replace petroleum-sourced polymeric materials for sustained economic development. However, challenges associated with sustainable production of lignocellulosic nanoscale polymeric materials (NPMs) need to be addressed. Producing materials from lignocellulosic biomass is a value-added proposition compared with fuel-centric approach. This report focuses on recent progress made in understanding NPMs—specifcally lignin nanoparticles (LNPs) and cellulosic nanomaterials (CNMs)—and their sustainable...

The established methods for determining the effects of ultrastructural changes in structural wood members rely upon traditional, possibly outmoded, testing paradigms. These methods usually involve destructive testing of wood specimens that are exposed to environmental conditions infrequently experienced in buildings. Understanding how the ultrastructure changes with time within the same specimen is crucial for building practitioners in assessing risks to lifesafety, assessing remaining service life of structural components, and aiding in the identification of mitigation or remediation...

In this study, we investigated the durability of adhesive bonds in the cross-laminated lumber of seven hardwood and two softwood species from the Great Lakes region. The 2-layered cross-laminations were glued using phenol resorcinol- and melamine-based structural adhesives. A total of 720 cross-laminated wood blocks were tested for delamination by exposing the samples to cyclic (wet-dry) conditions. Distribution of the adhesive on the bondlines was also studied to understand the effect of adhesive penetration on bond durability. The results indicated that mixed hardwood cross-laminations...

Chemical coprecipitation technique is proven to be a beneficial method to prepare uniformly mixed catalyst metal and Kraft lignin precursors. Coprecipitation is a simple, yet very complex process which is highly sensitive to the reaction conditions, particularly temperature. In an exothermic coprecipitation process, the reaction rate can become uncontrollable over certain temperatures which could lead to a thermal runaway reaction. In this work, metal-lignin nanocomposites were synthesized by coprecipitation of metal (M) salts and Kraft lignin. Kraft lignin and metal salts were dissolved...

Utility pole failures are a known cause of wildland fires. Over the past 15 years in the U.S. Department of Interior, Bureau of Land Management (BLM) Idaho Boise District, 299 wildland fires have been related to electric utility powerline structure failures, an average of 20 wildland fires per year. Routine inspection and maintenance would likely reduce the number of wildland fires caused by utility pole failures. The sheer number of poles and the great distances over which electrical lines span in the BLM Idaho Boise District are factors that complicate regular inspections. BLM recognizes...

Bark beetles and root weevils can impact forests through tree death on landscape scales. Recently, subterranean termites have been linked to these beetles via the presence of bluestain fungi (Ascomycota: Ophiostomataceae), which are vectored to trees by beetles. However, only a small subset of bluestain species have been examined. Here, we tested whether termite-bluestain association patterns in the field reflect termite feeding preference in laboratory choice trials. We documented the presence of four bluestain fungi (Leptographium procerum (W.B. Kendr.), L. terebrantis (Barras & Perry),...

As one of the most abundant and versatile natural materials on Earth, recently wood has attracted tremendous attention from scientists and engineers due to its outstanding advantages, including hierarchically porous microstructure, high mechanical strength, environmental friendliness, renewability, and biodegradability. Wood’s hierarchically porous structure and chemical components (e.g., cellulose, hemicelluloses, and lignin) enable its mechanical, ionic, optical, and thermal properties to be tuned via physical, chemical, and/or thermal modifications. Among these various approaches, the...

In cellulose materials, the cellulose II allomorph is often present either exclusively or in conjunction with cellulose I, the natural cellulose. Moreover, in regenerated and mercerized fibers (e,g., lyocell and viscose), natural cellulose adopts to the crystal structure cellulose II. Therefore, its detection and quantitation are important for a complete assessment of such materials investigations. In the Raman spectra of such materials, a band at 577 cm -1 is typically observed indicating the presence of this allomorph. In the present study, to quantify the content of cellulose II, a...

Colloidal lignin nanoparticles (LNPs) from low temperature acid hydrotropic fractionation (AHF) of poplar wood and commercial alkali lignin using p-Toluenesulfonic acid (p-TsOH) were directly mixed with PVA to make PVA/AHF-LNP nanocomposite films. p-TsOH itself acted as a plasticizer for PVA; however the application of p-TsOH alone reduced PVA film tensile strength and therefore toughness. At proper loadings of LNPs and p-TsOH, both the failure strain and tensile strength of PVA/AHF-LNP composites were improved. The formation of hydrogen bonding between the p-TsOH/AHF-LNP aggregates with...

Development of a novel and efficient inverse method for anisotropic material identification based on a complex-variable formulation of Airy stress function is presented. The overall equilibrium and compatibility, as well as the free traction along the boundary of the internal geometric cutouts, are analytically satisfied by means of conformal mapping and analytic continuation. The inverse problem is posed as an optimization problem where the objective functional is the difference between the measured data and its counterpart evaluated using the complex-variable method. Validity of the...