Treesearch

A desire to develop biorenewable materials has led to lactide caprolactone copolymers being used in adhesive, medical, and pharmaceutical products. Use of this alternative material may diminish human impact on the environment and create products that are biocompatible. One advantage of these materials compared with other typical petroleum-based polymers is that they are easily degraded by microorganisms. In this study, the biodegradation of representative lactide caprolactone macromonomers and an acrylic pressure sensitive adhesive incorporating these macromonomers was followed by a...

Tyloses are extruded cell contents of adjoining parenchyma cells that result in the obstruction of vessels. The function of tyloses in live trees is uncertain, but it has been proposed that they increase the natural durability of the wood by limiting water movement and the probing of fungal hyphae. Chestnut oak (Quercus montana, aka Quercus prinus) is inconsistent in producing tyloses; an initial study indicated a wide variation in the frequency of tyloses within and between trees of chestnut oak from three different states: VA, TN, and PA. This naturally occurring variation in tylosis...

Morphology analysis of cellulose nanocrystals (CNCs) using transmission electron microscopy (TEM) and atomic force microscopy (AFM) images is an important step in the design and optimization of the processes employed in the manufacture and utilization of CNCs. Current protocols used in the analyses of CNC particle morphology for such microscopy images are largely manual and time-consuming, and often produce inconsistent results between different researchers. This paper describes a new semi-automated image analysis framework that can reliably and quickly detect and classify CNCs from TEM...

January housing data showed the second consecutive month of total starts greater than 1.5 million units. However, total, single- and multifamily starts decreased month-over-month and year-over year. Aggregate (month-over-month and year-over-year) U.S. housing market data were mixed. New and existing house sales were positive month-over-month and year-over-year. Residential construction spending was positive month-over-month. On a year-over-year basis, total and single-family expenditures improved 21% and 24%, respectively.

Sheet molding compounds (SMC) are commonly used in automotive applications as they lead to increased fuel efficiency of vehicles due to their high strength to weight ratios. This study focuses on understanding the effect of replacing calcium carbonate (CaCO3) with hollow glass spheres (HGS) in an unsaturated polyester resin matrix SMC composite with the ultimate goal to further reduce density without compromising performance. The resulting glass fiber (GF)-reinforced syntactic foam laminate composites with GF content ranging from 10 to 15 vol% have densities of 1.2 and 1 g/cm3 , respectivel...

Waterborne acrylic coatings contain volatile and non-volatile coalescents. Volatile organic compound (VOC) coalescents enable film formation of hard acrylic polymers at ambient temperature, but their evaporation results in air pollution and health concerns. Non-volatile alternatives are available, but they remain in the coating long-term and as a result films are often tacky and lack adequate hardness. Reinforcing mineral fillers are available, but are associated with sustainability challenges inherent to mineral mining. An alternative approach demonstrated here utilizes a renewably-sourced...

Determining adhesive bond performance for chemically modifed wood is important not only for its commercial utility but also for understanding wood bond durability. Bulking modifications occupy space inside the cell wall, limiting the space available for water. We used two bulking modifcations on yellow poplar (Liriodendron tulipifera L.): acetylation (Ac), which bulks and converts a wood hydroxyl group to an ester, while butylene oxide (BO) also bulks the wood but preserves a hydroxyl group. Both result in lower water uptake; however, the loss of the hydroxyl group with Ac reduces the...

Cellulose nanomaterials (CNMs), mainly including nanofibrillated cellulose (NFC) and cellulose nanocrystals (CNCs), have attained enormous interest due to their sustainability, biodegradability, biocompatibility, nanoscale dimensions, large surface area, facile modification of surface chemistry, as well as unique optical, mechanical, and rheological performance. One of the most fascinating properties of CNMs is their aqueous suspension rheology, i.e., CNMs helping create viscous suspensions with the formation of percolation networks and chemical interactions (e.g., van der Waals forces,...

Specific heat capacity of eleven live foliar fuels from the southeastern United States was measured to 434 ◦C using differential scanning calorimetry to improve the modeling of prescribed fire behavior. Techniques which allow measurement of the standard heat capacity, excluding the effects of heat of reaction, were refined. Specific heat of leaves increased with temperature until the onset of pyrolysis. Once pyrolysis began, the specific heat became nearly constant. We present a simple model, suitable for incorporation in computer simulations, which captures this functional shape. This...

Thermo-hydro-mechanical (THM) processing can improve the intrinsic properties of wood, produce new materials, and give desired form and function to new applications. THM treatments change the mechanical properties of wood and may change its viscoelastic properties as well. Therefore, the objective of this study was to assess the viscoelastic properties of THM-treated wood at several humidity and load levels. To explore these changes, this study applied a THM treatment to beech (Fagus sylvatica L.) wood with steam (620 kPa) and heat (170 °C), followed by densifcation and increased temperatur...