Treesearch

This paper reports a facile one-pot method to produce graphene oxide nanocellulose composite (GNCC) that was subsequently reduced using L-ascorbic acid to form a conductive paper (CP). Cellulose fbers were directly added into the reaction system during graphite exfoliation using sulfuric acid to produce cellulose nano- or microfbrils through acid hydrolysis along with mechancial mixing. FTIR and Raman analyses indicated that reduction using L-ascorbic acid efciently produced a welldeoxygenated CP with high conductivity of 116.3±1.5 S m−1 at 20% graphene oxide loading. Furthermore, the...

Microstickies present a formidable challenge for papermakers. Many strategies have been explored to control them. Enzyme treatment is a promising technology, but the mechanism of its action has not been determined, thus inhibiting further application of this new technology. This study investigated characteristics and size distributions of microstickies treated by esterase-cellulase mixtures. Determination of particle size and number was accomplished using a modified flow cytometer, which combined streaming capillary flow, laser-based particle size analysis and fluorescent dye tracing. The...

In this study, 145 poplar (Populus × euramericana cv.’74/76’) seedlings, a common plantation tree species in China, were selected and their ultrasonic velocities were measured at four timepoints during the frst growth year. After that, 60 poplar seedlings were randomly selected and cut down to determine their acoustic velocity, using the acoustic resonance method. The effects of infuencing factors such as wood green density, microfbril angle, growth days, and root-collar diameter on acoustic speed in seedlings and the relationship between ultrasonic speed and acoustic resonance speed were...

Soy protein isolate (SPI) and insoluble soy four polymeric carbohydrates have been reacted with sodium periodate for the specifc oxidation of vicinal –OH groups to investigate the reactions involved in this approach to soy four adhesives. The reactions have been shown to generate carbohydrate oligomer fractions presenting one, two or multiple aldehyde groups. With the exception of the small molecular weight heptanedial, the smaller molecular weight aldehydes generated from mono- and disaccharides by the same reaction do not appear to form from the insoluble soy four carbohydrates, or have...

Functionalized cellulose particles were studied as a potential reinforcement for an unsaturated polyester resin (UPR) system, a common material for automotive applications of fiber reinforced plastics. A preliminary process for incorporating freeze-dried cellulose nanocrystal (CNC) powder into UPR was developed. Three surface chemistries were explored including sulfonated, methyl(triphenyl) phosphonium (PhCNC), and maleic acid (MCNC). By optical microscopy the filler was seen to be agglomerated within the matrix. Fractography showed that these agglomerates acted as stress concentration...

The focus of this study is to (i) understand the effect of the fiber type and content on the mechanical properties of sheetmolding compounds composites and (ii) investigate possible lightweight alternatives to glass fibers-sheet molding compound composites. Glass fiber and basalt fibers are used to make sheet-molding compound composites and the mechanical performance are determined as a function of the fiber type and content. In addition, cellulose nanocrystals are used to enhance the properties of the sheet-molding compound resin system. The possibility of lightweighting the basalt...

Reactive extrusion was used for dicumyl peroxide (DCP)-initiated grafting of glycidyl methacrylate (GMA) to poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). The effects of GMA and DCP content and their weight ratio on the GMA grafting percentage (GP%), the polymer melt viscosity, and the PHBV molecular weight were investigated. FTIR spectroscopy determined that the DCP did indeed initiate GMA grafting. However, the changes in both the zero-shear viscosity (η0) and the molecular weight suggested the existence of crosslinking products in the extruded polymers. A negative correlation...

Fraud and misrepresentation in forest products supply chains is often associated with illegal logging, but the extent of fraud in the U.S. forest products market, and the availability of forensic expertise to detect it, is unknown. We used forensic wood anatomy to test 183 specimens from 73 consumer products acquired from major U.S. retailers, surveyed U.S. experts regarding their forensic wood anatomy capacity, and conducted a proficiency-testing program of those experts. 62% of tested products (45 of 73) had one or more type of fraudulent or misrepresented claim. Survey respondents...

Cellulose nanomaterials have been demonstrated to improve the mechanical and barrier properties of various polymers, but numerous challenges, such as drying, remain to viably produce polymeric cellulose nanocomposites for packaging applications. In this paper we describe a method for drying and blending cellulose nanocrystals into polylactic acid (PLA) using a single process referred to as wet compounding. Aqueous suspensions of CNCs were directly compounded with PLA in a thermokinetic mixer in which viscous heating creates sufficient temperature to evaporate water and melt polymers during...

DNA barcoding is a promising tool to combat illegal logging and associated trade, and the development of reliable and efcient analytical methods is essential for its extensive application in the trade of wood and in the forensics of natural materials more broadly. In this study, 120 DNA sequences of four barcodes (ITS2, matK, ndhF-rpl32, and rbcL) generated in our previous study and 85 downloaded from National Center for Biotechnology Information (NCBI) were collected to establish a reference data set for six commercial Pterocarpus woods. MLAs (BLOG, BP-neural network, SMO and J48) were...