Treesearch

Carboxylated cellulose nanocrystals (OA-CNCs) isolated by aqueous recyclable oxalic acid hydrolysis from degreasing cotton were used to observe its self-assembly behavior and chiral nematic properties. The oxalic acid here served as the sole catalyst to esterify and hydrolyze the degreasing cotton. The results indicated that the obtained OA-CNC suspensions were spontaneously phase-separated into a chiral nematic mesophase above a critical concentration, and the occurrence of chiral self-assembly is highly dependent on the aspect ratio and the surface charge of the OA-CNC suspension....

Wood is one of the most abundant biomaterials on Earth, which has been used for centuries in construction applications including furniture, roofing, flooring, and cabinetry. However, wood chips—which are a low-quality and plentiful waste byproduct of lumber milling, woodworking, and shipping operations—have low economic value and complicated disposal methods. In this paper, we propose a strategy for wood chip reuse through the fabrication of bio-based building insulation foam. Through a high-temperature chemical treatment delignification process, we introduced additional small pores within...

The search for more-sustainable materials has motivated research on lightweight, porous structures for thermal insulation and noise reduction, such as for construction and cold-chain transportation. Wood, known as one of the most renewable materials on Earth, has been widely and long used in construction for its high strength/weight ratio, wide abundance, low cost and relative sustainability. However, natural wood is much less effective at reducing noise or preventing heat loss than conventional petroleum- and mineral-based porous structures (for example, expanded polystyrene foam and...

Cellulose nanofibril (CNF) substrates that are inexpensive, biodegradable, and quickly incinerable, are potential substrates for disposable RF applications. In this paper, high-performance flexible microwave lumped elements and filters fabricated on flexible CNF substrates are reported. A spiral inductor with a resonance frequency of 29.8 GHz and quality (Q) factor of 8.5 and a metal-insulator-metal (MIM) capacitor with a resonance frequency of 45 GHz and Q factor of 85.2 were achieved in a 200 μm thick CNF substrate. Meanwhile, the inductor and capacitor exhibit outstanding mechanical...

Sustainable timber use is vital to the health of American forests, and building materials represent a significant market for wood materials. However, due to the combustible nature of wood, wood building products are at risk of both becoming target fuel and contributing to the fuel load/fire spread. To reduce the risks, fire protection measures, such as fire-retardant treatments, can be employed. Here, a summary of current research related to the fire protection of wood building products is provided from exterior uses in the wildland-urban interface to interior applications for tall wood...

Lignin is a waste product in the paper industry and lignocellulosic biorefineries, in addition to being the second most abundant renewable biopolymer on Earth. Valorization of useless lignin into high value-added advanced materials not only helps address the environmentally detrimental biowaste but also satisfies the societal need for energy. While lignin has been converted into porous carbon, made into slurry, and pasted onto metal forms as an electrode for lithium-ion batteries and supercapacitors, there remains issues with how to scale up the process while achieving great area and mass...

Water vapor sorption is a fundamental characteristic of wood as a building material. Apart from empirical prediction, models are often used to interpret the time-dependent process of water vapor uptake (sorption kinetics) and equilibrium states of water in wood (sorption isotherms). This paper summarizes our recent investigations into measurement methods and popular models that are widely used for interpreting these physical phenomena. Commonly used criteria for determining equilibrium moisture content with the dynamic vapor sorption technique yield much larger errors than previously...

Though ballistic projectile penetration of wood has been studied for centuries, standard models overestimate the thickness of wood required to stop projectiles, often by a large margin. Adhesive lamination via contemporary manufacturing methods can produce mass timber panels of unprecedented thickness, yet industry standard layups of softwood cross-laminated timber (CLT) cannot stop projectiles traveling at velocities specified by current protective design requirements. To develop mass timber panels that comprehensively mitigate blast, ballistic, and forced entry threats, seven reinforced...

A mass timber lateral force resisting system (LFRS) is proposed using a timber buckling restrained brace (TBRB) for improved seismic performance in high seismic applications. To develop a high-performance braced frame, it is essential to quantify the behaviour of the connections including failure modes and moment-rotation capacities. Cyclic and monotonic tests were conducted on six mass timber beam-column connections to investigate the response of mass timber joints connected with slotted-in steel plates and mild steel dowels. The goal of the subassembly tests was to measure the maximum...

Quasistatic nanoindentation is a proven tool that provides information on the micromechanical behavior of wood cell walls. However, quasistatic tests cannot probe the time-dependent mechanical behavior shown by wood. Nanoindentation dynamic mechanical analysis (nanoDMA) can measure the viscoelastic properties of wood cell walls. This research aimed to study the quasistatic and viscoelastic properties of individual radiata pine wood (Pinus radiata D. Don) cell wall layers. To minimize variability and retrieve both properties at the same locations, a load function composed of a multiload-quas...