Treesearch

This study assessed the applicability of chitin nanocrystals employed in combination with an existing coating material intended for flexible packaging. The 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) oxidized chitin nanocrystals (TOCNs) were applied 1) as an additive in a water-based acrylic resin (WBAR) that was then coated onto the surface of a biaxially oriented polypropylene (BOPP) film, and 2) as a neat layer in multilayered BOPP laminates bonded by a WBAR adhesive layer. The results indicated that the flow behavior and shear viscosity of the TOCN/WBAR system were dependent on TOCN...

Bruce R. Johnson worked at the USDA Forest Service Forest Products Laboratory (FPL) from 1969-1994. His research as a Forest Products Research Technologist covered many aspects of wood durability and preservation. He was considered an expert on marine exposure of treated wood and wood based materials. His reports on marine performance of treated wood are influential publications still commonly cited in the current literature. To those of us who worked with him at FPL, Bruce was a motivating and inspiring colleague who loved his marine research, especially in Key West, Florida. Bruce was...

Wood is one of the primary construction materials used in the United States. However, it is susceptible to decay over time, leading to its reduced service life. Development of targeted wood protection methods requires detailed understanding of microbial wood-decay mechanisms. Fungi are the most destructive microorganisms to attack wood and much research effort has been directed towards understanding their mechanisms of decay. The role of bacteria in wood-decay is less studied. The objective of this research was to compare bacterial communities colonizing pressure-treated and untreated...

Wood, a complex hierarchical material, continues to be widely used as a resource to meet humankind’s material needs, in addition to providing inspiration for the development of new biomimetic materials. However, for wood to meet its full potential, researchers must overcome the challenge of understanding its fundamental moisture-related properties across its many levels of hierarchy spanning from the molecular scale up to the bulk wood level. In this perspective, a review of recent research on wood moisture-induced swelling and shrinking is presented from the molecular level to the...

This study is part of a research project examining fire risk in cross aminated timber (CLT) bui dings. “De amination”, a major concern for CLT fire safety, can occur when the adhesive bondline fails in the pane before it chars which can lead to additional fuel for fire regrowth. Understanding the mechanical strength and stiffness of the adhesive bond under elevated temperature is one of the fundamenta steps towards better understanding delamination. In this study, the materia properties of wood and wood adhesive bonds are studied at various temperatures levels below the char temperature of...

Enzymatic conversion of cellulosic biomass into fermentable sugars such as glucose is a slow and catalytically ineûcient process, largely due to limited accessibility of cellulose. Cellulose crystallinity can be reduced to increase substrate accessibility toward cellulolytic enzymes by either swelling or dissolving biomass in chemicals such as concentrated acids (e.g., phosphoric acid or H3PO4, sulfuric acid or H2SO4) or ionic liquids. Phosphoric acid swollen cellulose (PASC) is one such highly digestible form of regenerated amorphous cellulose (RAC), enriched along with some cellulose-II...

To ensure the safety of trees, two NDT (nondestructive testing) techniques, electric resistance tomography and stress wave tomography, were employed to quantitatively detect and characterize the internal decay of standing trees. Comparisons between those two techniques were done to make full use of the individual capability for decay detection.

A modern paradigm of soil organic matter proposes that persistent carbon (C) derives primarily from microbial residues interacting with minerals, challenging older ideas that lignin moieties contribute to soil C because of inherent recalcitrance. We proposed that aspects of these old and new paradigms can be partially reconciled by considering interactions between lignin decomposition products and redox-sensitive iron (Fe) minerals. An Fe-rich tropical soil (with C4 litter and either 13C-labeled or unlabeled lignin) was pretreated with different durations of anaerobiosis (0−12 days) and...

A simple and novel method, self-assembly of nanocellulose and nanochitin, was developed to produce high-efficiency and versatile biohybrid hydrogel (BHH) and aerogel (BHA) for water purification. The self-assembly process was driven by the electrostatic force between one-dimensional (1D) negatively charged TEMPO-oxidized cellulose nanofiber (TOCNF) and positively charged partly deacetylated chitin nanofiber (PDChNF). The self-assembly process was performed at room temperature and without adding any crosslinking agents throughout the process. This results in the threedimensional (3D) BHH...

There is an increasing attention to cellulose nanofibrils (CNFs) for food packaging applications due to their abundance, biodegradability, and low gas permeability. In this work, oxygen and water barrier performance is studied for bio-nanocomposite films formed by incorporation of two types of bentonite (PGN and PGV) at different loads (15, 30 and 45 wt%) into continuous CNF matrix. The resulting hybrid films were analyzed for their morphology, surface energy, mechanical strengths as well as water/oxygen barrier qualities. Both types of bentonite lowered the CNF degradation temperature and...