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A “green” oxyalkylation protocol employing ethylene carbonate (EC), polyethylene glycol 400 (PEG400), and water was developed to convert an industry byproduct, kraft lignin (KL), into biopolyols for the production of rigid polyurethane (RPU) foams. EC served as an oxyalkylation reagent for the derivatization of KL’s hydroxyl (OH) groups. PEG400 and water served as a co-solvent and a reactive additive, respectively, to tailor two properties of the KL-derived biopolyols, those being viscosity and OH number. For the oxyalkylated-KL (OKL), as characterized by 31P-nuclear magnetic resonance...

With increasing global water temperatures and nutrient runoff in recent decades, the blooming season of algae lasts longer, resulting in toxin concentrations that exceed safe limits for human consumption and for recreational use. From the different toxins, microcystin-LR has been reported as the main cyanotoxin related to liver cancer, and consequently its abundance in water is constantly monitored. In this work, we report a methodology for decorating cellulose nanofbrils with β-cyclodextrin or with poly(β-cyclodextrin) which were tested for the recovery of microcystin from synthetic...

Biodeterioration of building materials due to poor hygrothermal conditions is a major concern for the sustainability of buildings and the health and safety of occupants. The risks of biodeterioration are accentuated in high-efficiency buildings, requiring further design considerations. Researchers across the world have tried to characterize this issue through a combination of field experience, modeling, and controlled laboratory investigations. However, integration of these research outputs in building enclosure design analysis is an unfinished agenda, partly due to the lack of coordination...

Nanocellulose is conventionally produced from woody biomass including wood, crops and forest/agricultural residues, by top-down methods. Due to biomass recalcitrance, pretreatment, with a subsequent bleaching process, is mandatory to break down the resistance of the composite for nanocellulose extraction. In the present study, gamma-valerolactone (GVL) pulping without further bleaching/purification was used for producing cellulose nanomaterials from wood. GVL pulp and bleached kraft pulp from Aspen were comparatively studied as starting materials for (2,2,6,6-tetramethylpiperidin-1-yl)oxida...

It has been common practice to assume that a two-parameter Weibull probability distribution is suitable for modeling lumber strength properties. Verrill and others (papers published in 2012, 2013, 2014, and 2015) demonstrated theoretically and empirically that the modulus of rupture (MOR) distribution of a visual grade of lumber or of lumber that has been “binned” by modulus of elasticity (MOE) is not a two-parameter Weibull. Instead the tails of the MOR distribution are thinned via “pseudo-truncation.” Verrill and others (papers published in 2013 and 2014) performed simulations that...

The development of composite mass timber products in the late 20th century continues to generate new developments in the design and production of multi-layer wood products in a wide variety of orientations and for a wide variety of uses. In the US Congress’ Agricultural Act of 2014, provisions were specified in Section 7310 to establish a series of priorities for research into the needs of the forestry sector. Specifically, collaborative research efforts into the increased use of CLT in support of the expansion of this portion of the forest products industry were addressed. Cross laminated...

The standardized bridge design aides in this publication are for superstructures manufactured with glued-laminated timber (glulam) that was pressure-treated with preservatives. Four superstructure types are included: two longitudinal (slab-type) deck systems and two transverse deck systems resting on either glulam or steel girders. Simple span designs for both single- and multiple-lane bridges that conform to the American Association of State Highway Transportation Officials (AASHTO)–Load and Resistance Factor Design (LRFD) bridge design specifications are included.

Recent developments in image processing play a significant role in identifying and classifying features on ground penetrating radar (GPR) radargrams. Two groups of timber specimens were examined in this study. The first group comprised laboratory prepared Douglas-fir (Pseudotsuga menziesii) timber sections with inserts of known internal characteristics. The second group comprised timber girders salvaged from timber bridges on historic Route 66 that had been exposed to weather for more than 80 years. A subsurface interface radar system with a 2-GHz palm antenna was used to scan these two...

Ecofriendly materials such as polylactic acid (PLA) and cellulose nanocrystals (CNCs) are widely sought as potential substitute for petrochemical-based plastics. Uniform dispersion of cellulose nanocrystals in polymer matrices has inhibited their wide-spread application. In this study the influence of masterbatch preparation techniques on molecular structure, melt strength, rheological and dynamic mechanical properties of nanocomposite were systematically analyzed. Film casting and spin-coating methods were used to prepare masterbatches. Nanocomposites were obtained by masterbatch dilution...

Lignin, a byproduct from the chemical processing of lignocellulosic biomass, is a polyphenolic compound that has potential as a partial phenol substitute in phenolic adhesive formulations. In this study, HBr and HI were used as reagents to demethylate an alkali lignin (AL) to increase its hydroxyl content and thereby enhance its reactivity for the preparation of phenolic resins. Analyses by FT-IR, 1H-NMR and 2D-NMR(HSQC) demonstrated both a decrease in methoxyl groups and an increase in hydroxyl groups for each demethylated lignin (DL). In addition, the molar amounts of phenolic hydroxyls,...