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Described is the synthesis of diblock copolymers generated via sequential atom transfer radical polymerization (ATRP) of poly(n-butyl acrylate) (PnBA) followed by chain augmentation with either sulfonated poly(2-hydroxyethyl methacrylate) (PHEMA) or poly(2-hydroxyethyl acrylate) (PHEA) blocks. ATRP of PHEMA or PHEA from PnBA macroinitiator was conducted in acetone/methanol 50:50 (v/v) and produced diblock copolymers of low PDI (

This study demonstrated Sulfite Pretreatment to Overcome Recalcitrance of Lignocellulose (SPORL) for robust conversion of softwood through enzymatic hydrolysis. At a sodium bisulfite charge around 9%, over 90% cellulose conversion could be achieved when spruce wood chips were pretreated at 180°C with pH near 2. For lodgepole pine, pretreatment liquor initial pH had no effect on enzymatic cellulose conversion in the tested range of 1.9– 4.2 with a sodium bisulfite charge of 8%. The dissolution of glucan during pretreatment was only about 10%. Most of the hemicelluloses were recovered as...

The conversion of biomass, specifically lignocellulosic biomass, into fuels and chemicals has recently gained national attention as an alternative to the use of fossil fuels. Increasing the concentration of the biomass solids during biochemical conversion has a large potential to reduce production costs. These concentrated biomass slurries have highly viscous, non-Newtonian behavior that poses several technical challenges to the conversion process. A collaborative effort to measure the rheology of a biomass slurry at four separate laboratories has been undertaken. A comprehensive set of...

Detailed structural studies on the plant cell wall have traditionally been difficult. NMR is one of the preeminent structural tools, but obtaining high-resolution solution-state spectra has typically required fractionation and isolation of components of interest. With recent methods for dissolution of, admittedly, finely divided plant cell wall material, the wall can now be studied by solution-state NMR. Exploiting the dispersion of 2D (and even 3D) NMR allows strikingly detailed structural analysis of the wall components without the need for isolation and fractionation. The initial method...

Sieving methods have been almost exclusively used for feedstock size-reduction characterization in the biomass refining literature. This study demonstrates a methodology to properly characterize specific surface of biomass substrates through two dimensional measurement of each fiber of the substrate using a wet imaging technique. The methodology provides more information than sieving methods about biomass substrate. The measured dimensions of individual fibers were used to estimate the substrate external surface based on a cylinder model. The substrate specific surface and mechanical...

Blends based on recycled high density polyethylene (R-HDPE) and recycled poly(ethylene terephthalate) (R-PET) were made through reactive extrusion. The effects of maleated polyethylene (PE-g-MA), triblock copolymer of styrene and ethylene/butylene (SEBS), and 4,40-methylenedi(phenyl isocyanate) (MDI) on blend properties were studied. The 2% PE-g-MA improved the compatibility of R-HDPE and R-PET in all blends toughened by SEBS. For the R-HDPE/R-PET (70/30 w/w) blend toughened by SEBS, the dispersed PET domain size was significantly reduced with use of 2% PE-g-MA, and the impact strength of...

The economic crisis has not reduced the demand for wood energy, which is expected to continue to grow. The downturn in sawmill production caused a shortage of raw material supply for wood pellet producers. With decreased demand for pulpwood-quality roundwood for wood and paper products in 2009, some pulpwood is being converted into wood energy. Economies of scale are being increasingly utilized in both production and logistics to further expand the market volume. The pellet production level in Russia is gradually rising again, after stagnation in 2008. An ambitious policy of the Russian...

The Lake States region of Minnesota, Wisconsin and Michigan offers significant potential for bioenergy production. We examine the sustainability of regional forest biomass use in the context of existing thermal heating, electricity, and biofuels production, projected resource needs over the next decade including existing forest product market demand, and impacts on price and feasibility. Assuming $36 per dry tone at roadside, 4.1million dry tones of forest biomass could be available region-wide. However, less is likely available due to localized environmental and forest cover type constrain...

A vintage year for sawmilling 2008 was not. In an industry strongly driven to produce, we were apprehensive that firms would be more shy than usual about divulging their 2008 activities. So this year we cast a wider net but, in the end, 149 out of the 200 mills appearing on the Top 200 list, and 48 out of the top 50, volunteered their numbers. For the remainder, capacities usually serve as a good proxy because most mills strive to operate near their limits in good years. This year, however, that approach was unreliable because operating rates varied widely. Among our respondents they...

The North American wood pellet sector is profiled in this paper. A small pellet industry has existed since the 1930s, but its main growth occurred in the wake of the energy crisis in the 1970s. Its current spurt is even greater, growing from is set to reach 6.2 million in 2009. Most plants are small, relying on sawmill residues for fiber and thus are limited to 100,000 tonnes or less per year. A number of new mills have been built to process chipped roundwood and have capacities three to four times as large. Most pellets made in the United States are consumed domestically, but a growing...