Treesearch

The forest products industry accounts for approximately 6% of total U.S. manufacturing output; nanotechnology could play an increasing role. As with any emerging technology, cellulose nanomaterials may become commercially available in a range of products before society obtains sufficient knowledge of the risk they pose to workers, consumers, and the environment. In partnership with the Forest Products Laboratory, the National Institute for Occupational Safety and Health conducted an exposure characterization study of the production of cellulose nanocrystals (CNC) that had been tagged with...

The effect of drying method on selected material properties of nanocellulose was investigated. Samples of nanofibrillated cellulose (NFC) and cellulose nanocrystals (CNC) were each subjected to four separate drying methods: air-drying, freeze-drying, spray-drying, and supercritical-drying. The thermal stability and crystallinity of the dried nanocellulose were evaluated using thermogravimetric analysis (TGA) and X-ray diffraction. Supercritical-drying produced NFCs with the least thermal stability and the lowest crystallinity index. Air-drying or spray-drying produced NFCs which were more...

ASTM(1) G198, Standard test method for determining the relative corrosion performance of driven fasteners in contact with treated wood, was accepted by consensus and published in 2011. The method has two different exposure conditions for determining fastener corrosion performance in treated wood. The first method places the wood and embedded fasteners in a chamber at 95% relative humidity (RH), 32 °C for 120 days. The second method involves a cyclic fog, with 48 hours of fog followed by 72 h of dry for 120 days. The corrosion rate of embedded metals is an extremely sensitive function of...

Potassium methyl siliconate (PMS) was investigated as a new nano modifier of wood fiber and wood flour to improve the compatibility between the fiber/flour and the plastic matrix in fiber reinforced plastic composites. Before injection molding, bleached and brown pulp fibers and mixed species wood flour were pretreated in PMS solutions. The morphology of the treated and untreated fiber and flour, the compatibility of PMS-treated fiber and flour with polyethylene (PE), and the water sorption and volumetric swell of PMS-treated fiber/flour plastic composites in a long-term soaking test were...

The Fiber and Chemical Sciences Research Work Unit at the Forest Products Laboratory began working out the preparation of cellulose nanocrystals in 2006, using the method of Dong, Revol, and Gray. Initial samples were provided to several scientists within the Forest Service. Continued requests for this material forced scale-up from the initial 20 g scale to kg scale and eventually resulted in an award of $1.7 million dollars to the laboratory to purchase the equipment needed to scale production up to 20 kg per batch. The new pilot facilities started up in July 2012 with batch sizes of 15...

Flexible electronics have a large number of potential applications, including malleable displays and wearable computers. Current research into high-speed, flexible electronic substrates uses plastics for the flexible substrate, but these plastics typically have drawbacks, such as high thermal expansion coefficients. Transparent films made from cellulose nanofibrils (CNFs) have low thermal expansion and therefore the potential to serve as substrates for flexible electronics. Initial results show that cellulosic nanomaterials are promising candidates for electronic substrates, and research...

Soy flour adhesives using polyamidoamine-epichlorohydrin (PAE) resin as the curing agent are being used commercially to make bonded wood products. The original studies on the soy-PAE adhesives used purified soy protein isolate, but the much lower cost soy flour is now used commercially. We examined the performance of commercially available soy flours that have their proteins either mainly in their native (90 protein dispersibility index (PDI)) or denatured (70 and 20 PDI) states. We expected that the more native state soy proteins with their better dispersibility would provide better...

Simultaneous saccharification and co-fermentation (SSCF) process involves enzymatic hydrolysis of pretreated lignocellulosic biomass and fermentation of glucose and xylose in one bioreactor. The optimal temperatures for enzymatic hydrolysis are higher than the standard fermentation temperature of ethanologenic Saccharomyces cerevisiae. Moreover, degradation products resulting from biomass pretreatment impair fermentation of sugars, especially xylose, and can synergize with high temperature stress. One approach to resolve both concerns is to utilize a strain background with innate tolerance...

Considering that crystallinity is one of the important properties that influence the end use of cellulose nanomaterials, it is important that the former be measured accurately. Recently, a new method based on near-IR FTRaman spectroscopy was proposed to determine cellulose I crystallinity. It was reported that in the Raman spectrum of cellulose materials, the peak intensity ratio of 380 and 1,096 cm-1 bands can be used to determine cellulose crystallinity. Raman crystallinities of the calibration-set Whatman CC31 samples were correlated with the WAXS data (Segal- WAXS-21°; coefficient of...

Raman spectroscopy was used to analyze cellulose nanocrystal (CNC)-polypropylene (PP) composites and to investigate the spatial distribution of CNCs in extruded composite filaments. Three composites were made from two forms of nanocellulose (CNCs from wood pulp and the nanoscale fraction of microcrystalline cellulose), and two of the three composites investigated used maleated PP as a coupling agent. Raman maps based on cellulose and PP bands at 1098 and 1460 cm-1 respectively and obtained at 1 micron spatial resolution showed that the CNCs were aggregated to various degrees in the PP...