BACKGROUND: Solvent based pretreatment of biomass followed by enzymatic hydrolysis (in the presence of the solvent- 'in situ hydrolysis') is an attractive route to develop a biorefinery concept since it reduces a number of washing steps to remove the solvent and saves energy. This work explores the ability of the commercial 'Iyocell' solvent- N-methyl Morpholine N-Oxide (NMMO) for 'in situ' hydrolysis at high cellulose loadings and compares its hydrolysis performance with commercially available ionic liquids (ILs).RESULTS: NMMO is able to dissolve high loadings of cellulose which on subsequent in situ enzymatic hydrolysis results in not only an increased sugar yield (similar to 30 mg mL(-1)) but also an enhanced rate of hydrolysis (12.24 mg mL(-1) h(-1)). In addition, a comparative study of hydrolysis in the presence of NMMO and ILs reveals the fact that hydrolysis in NMMO produces the highest sugar yields when compared with ILs.CONCLUSION: This study thus establishes the effectiveness of NMMO as a pretreatment solvent- it is an excellent solvent for disrupting the microstructure and dissolving high loadings of cellulose, and hydrolysis reactions can be carried out in the presence of NMMO since enzymes are active in its presence. (C) 2016 Society of Chemical Industry

Cellulose/1-butyl-3-methylimidazolium chloride ([Bmim]Cl) solutions were wet spun at varied concentrations, temperatures and draw down ratios using a semi-hyperbolically converging die to produce fibers that were highly oriented and highly crystalline. The orientation number (NOR) and the Herman's orientation factor (f(H)) were compared with the fiber crystallinity. The analysis of the results indicates that the spinning parameters had a significant effect on the fiber properties, especially the orientation factor as well as the orientation number. Therefore, to spin cellulose fibers that would be suitable for carbon fiber precursors, the spinning parameters are a high concentration solution at approximately 90 degrees C and at a medium draw ratio. This would yield fibers with a high orientation number. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 128:951-957, 2013

A true biorefinery for processing lignocellulosic biomass should achieve maximum utilization of all major constituents (cellulose, hemicellulose, & lignin) within the feedstock. In this work a combined pretreatment process of dilute acid (DA) and N-methyl morpholine N-oxide (NMMO) is described that allows for both fractionation and subsequent complete hydrolysis of the feedstocks (corn stover and sugarcane bagasse). During this multi-step processing, the dilute acid pretreatment solubilizes the majority (>90%) of the hemicellulosic fraction, while the NMMO treatment yields a cellulosic fraction that is completely digestible within 48 hours at low enzyme loadings. With both the cellulosic and hemicellulosic fractions being converted into separate, dissolved sugar fractions, the remaining portion is nearly pure lignin. When used independently, DA and NMMO pretreatments are only able to achieve ~80% and ~45% cellulosic conversion, respectively. Mass balance calculations along with experimental results are used to illustrate the feasibility of separation and recycling of NMMO.

I will describe a UK project to establish a 10-20 PW capability on the Vulcan Laser at the Rutherford Appleton Laboratory based on the OPCPA technique. Design, new technology, science and status will be covered. Article not available.

Overcoming the recalcitrance (resistance of plant cell walls to deconstruction) of lignocellulosic biomass is a key step in the production of fuels and chemicals. The recalcitrance is due to the highly crystalline structure of cellulose which is embedded in a matrix of polymers-lignin and hemicellulose. The main goal of pretreatment is to overcome this recalcitrance, to separate the cellulose from the matrix polymers, and to make it more accessible for enzymatic hydrolysis. Reports have shown that pretreatment can improve sugar yields to higher than 90% theoretical yield for biomass such as wood, grasses, and corn. This paper reviews different leading pretreatment technologies along with their latest developments and highlights their advantages and disadvantages with respect to subsequent hydrolysis and fermentation. The effects of different technologies on the components of biomass (cellulose, hemicellulose, and lignin) are also reviewed with a focus on how the treatment greatly enhances enzymatic cellulose digestibility.

The elongational rheology of solutions of cellulose in the ionic liquid solvent 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) was measured at 80, 90, and 100 degrees C; 8, 10, and 12 wt% cellulose; Hencky strains 5, 6, 7; and strain rates from 1 to 100 s(-1). Master curves were generated by shifting the elongational viscosity curves with respect to temperature and Hencky strain. Also, general master curves were generated by simultaneously shifting with respect to both temperatures and Hencky strain. From the Arrhenius plots of the temperature shift factors, the activation energy for elongational flow was deter-mined. The elongational rheology of these solutions was elongational strain rate thinning similar to that of their shear behavior and polymer melts and they were also strain hardening. Both effects and the viscosity increased with cellulose concentration. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 110: 3203-3208, 2008

Int his article, shear rheology of solutions of different concentrations obtained by dissolution of cellulose in the ionic liquid (IL) solvent 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) was studied by measuring the complex viscosity and dynamic moduli at different temperatures. The obtained viscosity and dynamic moduli at different temperatures. The obtained viscosity curves were compared with those of lyocell solutions and melt blowing grade polypropylene melts of different melt flow rates (MFR). Master curves were generated for complex viscosity and dynamic moduli by using Carreau and Cross viscosity models to fit experimental data. From the Arrhenius plots of the shift factors with respect to temperature, the activation energies for shear flow were determined. These varied between 18.99 and 24.09 kCal/mol, and were compared with values for lyocell solutions and different polemeric melts, such as polyolefins, polystyrene, and polycarbonate. (c) 2008 Wiley Periodicals, Inc.

The focus of this article of a three part series is the effects of preparation and composition on the shear rheology of cellulose in the ionic liquid 1-butyl-3-methylimidazolium chloride ([Bmim]Cl). Included are the effects of three different degrees of polymerization, (i.e., average molecular weight), manual versus high shear mixing, a range of cellulose concentrations, and the effects of controlled amounts of lignin and a hemicellulose. The rheology implies that a gel phase develops at higher degrees of polymerization, higher concentration, and at lower temperatures. The first article focused primarily on shear rheology of cellulose in [Bmim]Cl with a high shear preparation technique, one degree of polymerization, a narrow range of cellulose concentrations, and temperature. The third article focuses on elongational rheology of cellulose in [Bmim]Cl. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

The elongational viscosities of polyethylenes with different molecular characteristics were measured at different Hencky strains and temperatures with a capillary rheometer by the replacement of the capillary cylindrical die with a hyperbolic converging die. The hyperbolic shape of the die established a purely elongational flow field at a constant elongational strain rate throughout the die. The effects of molecular characteristics such as the molecular weight, molecular weight distribution, and long-chain branching and processing conditions such as the temperature and Hencky strain on the elongational rheology of the polyethylene samples were studied. Good master curves were generated for temperature and Hencky strain shifting and simultaneous shifting with respect to both the temperature and Hencky strain. Both the molecular weight distribution and long-chain branching seemed to promote strain rate thinning and reduce the elongational viscosity. (c) 2007 Wiley Periodicals, Inc.

The elongational rheology of polymer melts was measured by the authors using the hyperbolic convergent die technique and the results were compared with the same samples measured using a Meissner type device or an Instron tensile tester. Polyethylene and polystyrene samples were tested at Eidgenossische Technische HochschuleZurich or Virginia Polytechnic Institute, and the polyisobutylene was part of a world wide "Round Robin" comparison. A modified Weissenberg number, i.e., an Orientation number, is suggested to explain the agreement between techniques for some samples and lack of agreement for others. The Orientation number is the product of Hencky strain, elongational strain rate, and average relaxation time. When it is less than one a relaxation dominant regime results, when greater than one an orientation dominant regime results, and near one a transition occurs. For the hyperbolic convergent die technique, in which the polymers are transversely constrained by the walls, the extrudates in the transition regime have slight surface defects and the pressure fluctuates more than in the other regimes. If the transition occurs after significant time, i.e., lower elongational strain rates, in the free boundary Meissner and Instron devices, the samples apparently experience more relaxation since unconstrained transversely (and perhaps differential thinning) leading to disagreement with the hyperbolic die measurements. The orientation related body forces are magnitudes larger than the shearing forces and cause slip at the wall in the hyperbolic dies in the orientation dominant regime. Even in the relaxation dominant regime, shear near the wall is a minor contributor to the necessary pressure force. (c) 2007 Wiley Periodicals, Inc.

The effective elongational viscosity data on a series of polyolefins as a function of temperature are shifted to a reference temperature using the approach for shifting shearing viscosity data. The temperature shift factors are obtained from complex and capillary shear rheology, and these are the same factors used for shifting the shear rheology. A Carreau rheological model was used to determine the zero shear rate viscosity at different temperatures, and an Arrhenius expression was used to determine the temperature shift factors. The same shift factors are shown to produce separate master curves for shear and elongational rheology at reference temperatures. The commercial grades of polyolefins studied include an extrusion grade of polypropylene and metallocene and conventionally catalyzed low and high density polyethylene materials. (C) 2002 Wiley Periodicals, Inc.

The effective elongational viscosity data on a series of polyolefins as a function of the Hencky strain are shifted to a reference Hencky strain using an approach similar to that used for temperature shifting, shearing viscosity data. The basis of this shifting is the order that develops (i.e., the decrease in entropy that occurs) during forced flow through sernihyperbolically convergent dies. The entropy decrease is proportional to the orientational contribution to the effective elongational viscosity. The Hencky strain shift factors are obtained from the convergent flow effective elongational rheology and the complex and capillary shear rheology. The commercial grades of polyolefins studied include polypropylene, high density polyethylene, and metallocene and conventionally catalyzed low density polyethylene. The combination of the temperature shift factors given in our companion article and the Hencky strain shift factors in this article enable the creation of master curves for the effective elongational rheology. (C) 2002 Wiley Periodicals, Inc.

Elongational and shear rheology of solutions of cellulosic and lignocellulosic materials in N-methylmorpholine oxide monohydrate (NMMO) was investigated for a variety of parameters. Both effective elongational and shear viscosity show a "thinning effect". A strong orientation effect was noticed by calculating the body forces, enthalpy and entropy of orientation. This is particularly significant at low temperatures and high deformation rates. Also, another common trend for cellulosic and lignocellulosic solutions in NMMO is the transition at about 90, as revealed by tan 8 temperature plots at different frequencies in Dynamical Mechanical Analysis measurements.

Recycling of cotton (or rayon) cellulose as lyocell fibers is proposed based on the selective solubility of cellulose in organic N-oxides and the selective hydrolysis of polyesters in NaOH solutions. In the first step, the cotton component of a fabric made of 50/50 cotton/polyethylene terephthalate was separated from the polyester by basic hydrolysis of the latter in NaOH solutions. In the second step, the cellulose component from another sample of the same fabric was selectively dissolved in N-methyl morpholine monohydrate to form a 1-2% cellulose solution. It was then concentrated to a spinable 15-17% solution by dissolving the cotton separated in the first step. Lyocell fibers were subsequently spun at 85-90C using an advanced capillary extrusion rheometer system.