Treesearch

Surface coatings of melamine-modified urea-formaldehyde resins (MUFs) containing ammonium polyphosphate (APP) have been shown to significantly improve the fire retardancy of wood by prolonging the ignition time and reducing the heat release rate, total heat released, and mass loss rate. Dual protection of wood against both decay and fire has been proposed for remedial situations and interior construction. In this study, the fire retardant MUF resin type 3 (MUF3)/APP mixture system showed strong activity against wood decay fungi via an activity inhibition test. Two species of wood were...

Paper is an excellent candidate to replace plastics as a substrate for flexible electronics due to its low cost, renewability and flexibility. Cellulose nanopaper (CNP), a new type of paper made of nanosized cellulose fibers, is a promising substrate material for transparent and flexible electrodes due to its potentially high transparency and high mechanical strength. Although CNP substrates can achieve high transparency, they are still characterized by high diffuse transmittance and small direct transmittance, resulting in high optical haze of the substrates. In this study, we proposed a...

This study evaluated batch fermentation modes, namely, separate hydrolysis and fermentation (SHF), quasi-simultaneous saccharification and fermentation (Q-SSF), and simultaneous saccharification and fermentation (SSF), and fermentation conditions, i.e., enzyme and yeast loadings, nutrient supplementation and sterilization, on high titer bioethanol production from SPORL-pretreated Douglas-fir forest residue without detoxification. The results indicated that Q-SSF and SSF were obviously superior to SHF operation in terms of ethanol yield. Enzyme loading had a strong positive correlation with...

This article describes a facile route, which combines mild maceration of waste pulp sludge and a mechanical shearing process, to prepare microfibrillated cellulose (MFC) with a high storage modulus. In the maceration, the mixture of glacial acetic acid and hydrogen peroxide was used to extract cellulose from never-dried waste pulp sludge. Then, two different mechanical processes including disc refining (DR) and ultrasonication plus homogenization (UH) were applied to the cellulose after maceration and resulted in MFC with a highly tangled fibril network. All of the resultant cellulosic...

Two biorefinery lignosulfonates (LSs), Ca-LS-DF and Na-LS-LP were, respectively, isolated from pilot-scale sulfite-pretreated spent liquor of lodgepole pine and fermentation residue of Douglas-fir harvest forest residue. The molecular weights of Na-LS-LP and Ca-LS-DF were approximately 9 000 and 11 000 Da, respectively. The two LSs were applied as dispersant for graphite in aqueous suspensions. The dispersion stability was evaluated by a scanning electron microscope and Turbiscan Lab Expert. LS performance in modifying graphite was better than that of a commercial dispersant Reax-85A as...

Trend data through 2011 are provided on the value and volume of wood and wood products production for the United States to aid in assessing sustainability of socioeconomic benefits of forests. The volume of roundwood used to make products, the weight produced, and the value of U.S. shipments have fluctuated in recent years. But there have been decreases in the weight of oriented strandboard production and the value of furniture production. U.S. demand for products is likely to continue to increase with increasing population and gross domestic product. If the cost of providing wood products...

This article presents the design optimization of an un-notched Iosipescu test specimen whose goal is the characterization of the material elastic stiffnesses of a Loblolly (Pinus taeda) or Lodgepole pine (Pinus contorta) sample in one single test. A series of finite element (FE) and grid simulations were conducted to determine displacement and strain fields for various ring angles, ring spaces, and proportions of latewood per ring. These displacement and strain fields were utilized to determine the constitutive parameters for the woody material using VFM. Using an error function based on a...

Cladophora, a fresh-water green macroalgae, has unique cellulose properties and thus may be promising for production of cellulose nanofibrils (CNFs). Cellulose was extracted from Cladophora glomerata and subjected to microfluidization with or without enzymatic hydrolysis pretreatment to produce CNFs. Increasing microfluidization passes produced smaller algal CNFs with more uniform sizes and lower crystallinity. Combining microfluidization with an enzymatic hydrolysis pretreatment, the algal CNFs’ crystallinity decreased further, but the diameter distribution showed little change. The algal...

The unequal reactivity of the two isocyanate groups in an isophorone diisocyante (IPDI) monomer was exploited to yield modified cellulose nanocrystals (CNCs) with both urethane and isocyanate functionality. The chemical functionality of the modified CNCs was verified with ATR-FTIR analysis and elemental analysis. The selectivity for the secondary isocyanate group using dibutyl tin dilaurate (DBTDL) as the reaction catalyst was confirmed with 13C NMR. The modified CNCs showed improvements in the onset of thermal degradation by 35 °C compared to the unmodified CNCs. Polyurethane composites...

We report the effect of lignin-coated cellulose nanocrystals (L-CNCs) on the crystallization behavior of poly(lactic acid) (PLA). PLA/L-CNC nanocomposites were prepared by melt mixing, and the crystallization behavior of PLA was investigated using differential scanning calorimetry. Isothermal crystallization data were analyzed using Avrami and Lauritzen–Hoffman secondary nucleation theory, while the equilibrium melting temperature was determined using the nonlinear Hoffman–Weeks method. The lignin-coated cellulose nanocrystals acted as a nucleating agent and significantly increased the...