Increasing Cellulose Concentration Research Articles

Characteristics of bioplastics prepared from cassava starch reinforced with banana bunch cellulose at various concentrations

Human activities have led to the pollution of the environment through the accumulation of plastic waste. Since plastics are resistant to decomposition resulting negative impact on the environment, there is a pressing need for the development of bioplastics. Starch is a such of natural material that can be used made of bioplastics. However, bioplastics from starch were needed to improve starch-based bioplastics due to their brittle properties. To address this issue, researchers focused on enhancing starch-based bioplastics by incorporating cellulose, particularly derived from kepok banana bunch fibers and cassava starch variety UJ3. The production process involved adding varying concentrations of 2.5, 5, 7.5, and 10 % (wt) of kepok banana bunch cellulose. The findings indicated that increasing cellulose concentration improved the characteristics of the bioplastic materials significantly. The results showed that the addition of cellulose concentration improved the mechanical properties, water vapor absorption, and biodegradability of bioplastics. With an optimal cellulose concentration level at 7.5%, remarkable enhancements in tensile strength (from 2.92 to 6.72 MPa), reduced elongation percentage (from 20.89 to 4.06%), increased Young’s Modulus values (from 13.98 to 172.52 MPa), decreased water vapor absorption rate (from 15,93 to 11,48%), and enhanced bio-degradability rating (from 29,81 to 50,69%) were observed.

Interactions of cellulose cryogels and aerogels with water and oil: Structure-function relationships

Food-grade porous materials, aerogels and so-called cryogels, were prepared from cellulose hydrogels obtained from solutions at increasing cellulose concentration (3, 4, 5%, w/w) by supercritical-CO2-drying (SCD) and freeze-drying (FD), respectively. The structure depended on the applied drying technique, with aerogels showing a denser network with pores <200 nm in diameter, a specific surface area of 370–380 m2g-1, and a porosity of 92–94%. Cryogels presented larger pores (2–5 μm diameter), much lower specific surface area (around 30 m2g-1), and higher porosity (95–96%). Water vapor adsorption by aerogels and cryogels was higher than that of neat microcrystalline cellulose. The absorption of water and oil was investigated as a function of time and at equilibrium. While water was almost immediately absorbed by both aerogels and cryogels, a much longer time was needed to reach oil absorption equilibrium. Moreover, aerogels required a longer absorption time than cryogels. Material morphology governed the kinetics of absorption; the absorption at equilibrium was directly dependent on material pore volume rather than on its morphology or material-fluid affinity. As a result, due to their lower pore volume, aerogels absorbed a lower amount of water or oil (4–8 gfluid/gdry matter) than cryogels (8–12 gfluid/gdry matter). All samples showed high fluid holding capacity (>96%). Water absorption caused a firmness decrease, but the firmness of oil-filled materials was the same as that of the unloaded ones. This study demonstrates that food-grade cellulose aerogels and cryogels can be structurally designed by varying cellulose concentration and drying techniques to obtain controlled food fluid loading.

Dissolution of HwBKP with [Bmim]Cl-DMF Solvent and Production of Cellulose Beads: Effect of the Cellulose Concentration and Syringe Needle Diameter

This study investigated the effects of cellulose concentration dissolved in 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) and N,N-dimethylformamide (DMF) on the properties of cellulose solution and beads. Cellulose beads were prepared using the dropping method. The cellulose solution dissolved in [Bmim]Cl and DMF (mixing ratio=70:30) did not gel for 12 h and exhibited shear thinning behavior. Increasing the cellulose concentration increased the viscosity and surface tension of the cellulose solution. Cellulose beads, 600-1000 μm in size, were prepared by varying the cellulose concentration in the range of 2-4% and the syringe needle diameter in the range of 0.3-0.9 mm using the dropping method. The particle size of the beads increased with increasing cellulose concentration and diameter of the syringe needle. The cellulose concentration had no remarkable effect on the chemical structure, crystallinity, and thermal stability of cellulose.

Bioinspired Cellulose Foam with Excellent Water Wicking and Flux Properties Prepared Using Ice Template.

The application and functionalization of cellulose has been attracting increased attention in academic and industrial studies because of its wide range of sources, short renewable cycle, and low environmental impact. In order to enhance the application field of cellulose and decrease the environmental pollution for organic solvent associated with its preparation, cellulose foam with a vertically hierarchically porous structure similar to wood was designed and fabricated successfully from a cellulose aqueous solution using an ice templated in this study. The cellulose foam prepared using a 3 wt % concentration possessed a uniform vertical hierarchically porous structure, which could provide a pathway for the flow of water or air based on the capillary effect. The highest water wicking rate and flux were 7.8184 mm·s-1 and 29.49 mL·min-1·g-1, respectively, for the porous foam prepared using a 3 wt % concentration. The mechanical testing experiment showed that the porous structure did not reduce the amount of stress that the sample could endure before being damaged. The compression strength increased with increasing cellulose concentration in solution. Therefore, the hierarchical structure formed in the prepared cellulose foam effectively improved the water flux behavior and provided a structural basis for future applications of cellulose scaffolds.

Rheology of PLA/regenerated cellulose nanocomposites prepared by the pickering emulsion process: Network formation and modeling

PLA/regenerated cellulose (RC) nanocomposites containing 0.5, 1.0, 1.5, 2.0, 3.0 and 5.0 wt% cellulose were prepared by the Pickering emulsion process. The structure and the rheological properties of the composites were characterized by microscopy, the measurement of melt flow rate and oscillatory rheometry. Viscosity was modelled with the modified Carreau-Yasuda and the modified Cross models, and a new model was proposed as well. The results show that RC is a suitable reinforcement for PLA and the Pickering emulsion process produces homogeneous material. Good dispersion and the relatively large aspect ratio of the cellulose nanofiller leads to the formation of a network structure already at small cellulose content. Viscosity increases rapidly with increasing cellulose concentration and a yield stress appears already at 0.5 wt% RC content. Modeling helps the quantitative analysis of the experimental results and offers additional information about the structure and properties of the composites studied. All three models predict yield stress well, but only the new model gives reasonable values for the power law exponent. Other parameters and their composition dependence are difficult to interpret.

Production and characterization of PVA/alginate composite filament with cellulose from oil palm empty fruit bunches

Cellulose is a renewable natural polymer that has abundant availability in the Earth and found in oil palm empty fruit bunches (OPEFBs). OPEFBs is one of the biomass produced from the crude palm oil industry. Cellulose fibers were isolated by alkaline treatment and bleaching. Cellulose from OPEFBs can be utilized as filament material by mixing it with polyvinyl alcohol (PVA) and alginate. In this work, OPEFBs cellulose/PVA/alginate composite filaments were produced by the wet spinning method with 9 wt% CaCl2 as a coagulant solvent and characterized. The effect of composite formulation on mechanical, morphological, crystallinity, and thermal properties of filaments was observed. The observed result shows that the increasing cellulose concentration had excellent thermal stability, higher crystallinity, with the morphology of the surface became rougher than 0% cellulose filament. The addition of cellulose had a significant effect on the mechanical properties of filaments, increasing the tensile strength and decreasing the elongation of filaments.

Chain dynamics and glass transition of dry native cellulose solutions in ionic liquids.

Dry native cellulose solutions in 1-butyl-3-methylimidazolium methylphosphonate (EMImMPO3H), 1-butyl-3-methylimidazolium acetate (EMImAc), and 1-butyl-3-methylimidazolium chloride (BMImCl) ionic liquids (IL) were investigated using subambient linear viscoelastic oscillatory shear. Glass transition temperatures (Tg) of solutions with various cellulose concentrations up to 8.0 wt% were observed as the peaks of loss tangent tan(δ) and loss modulus G'' in descending temperature sweeps at 1 rad s-1. Cellulose/IL solutions showed a minimum in Tg at ∼2.0 wt% cellulose content before increasing with cellulose concentration, suggesting a perturbation of the strongly structured IL solvents by the cellulose chains. Isothermal frequency sweeps in the vicinity of Tg were used to construct time-temperature-superposition master curves. The angular frequency shift factor aT as a function of temperature indicates Arrhenius behavior within a 9 K range near Tg, allowing calculation of fragility, which was found to be constant up to 8.0 wt% cellulose concentration. This result implied that increasing cellulose concentration initially decreases Tg due to disrupted ionic regularity of ILs, but does not seem to change their fragility.

OPTIMIZATION OF HYDROTHERMAL PRETREATMENT FOR ENZYMATIC HYDROLYSIS OF BANANA PSEUDO STEM USING RESPONSE SURFACE METHODOLOGY

In this study different conditions of hydrothermal pretreatment were evaluated for conversion of banana pseudo stem to fermentable sugars. A Central Composite Design (CCD) was used to obtain regression equations in function of the following variables: solid/liquid ratio (1/10; 1/12.5; 1/15), temperature (170 °C, 190 °C, 210 °C) and reaction time (10 min, 15 min, 20 min). The cellulose digestibility improved in all conditions tested, with maximum digestibility achieved at 210 °C for 10 minutes and 1/15 of solid/liquid ratio. The Glucose yield at optimal conditions was 58.4 g/kg with an excellent recovery of cellulose of 98%. Thus, the hydrothermal pretreatment demonstrated to be an effective process in increasing cellulose concentration and producing fermentable sugar from recalcitrant lignocellulosic biomass. Furthermore, based on the design response surface methodology, an optimum condition of each pretreatment could be obtained from the statistical models built. All the variables studied influenced the enzymatic sugar release.

Selective Cellulose Hydrogenolysis to Ethanol Using Ni@C Combined with Phosphoric Acid Catalysts.

Ethanol is an important bulk chemical with diverse applications. Biomass-derived ethanol is traditionally produced by fermentation. Direct cellulose conversion to ethanol by chemocatalysis is particularly promising but remains a great challenge. Herein, a one-pot hydrogenolysis of cellulose into ethanol was developed by using graphene-layers-encapsulated nickel (Ni@C) catalysts with the aid of H3 PO4 in water. The cellulose was hydrolyzed into glucose, which was activated by forming cyclic di-ester bonds between the OH groups of H3 PO4 and glucose, promoting ethanol formation under the synergistic hydrogenation of Ni@C. A 69.1 % yield of ethanol (carbon mole basis) was obtained, which is comparable to the theoretical value achieved by glucose fermentation. An ethanol concentration of up to 8.9 wt % was obtained at an increased cellulose concentration. This work demonstrates a chemocatalytic approach for the high-yield production of ethanol from renewable cellulosic biomass at high concentration.

Differences in physiological traits and resistances of Alternanthera philoxeroides after herbivory by generalists and specialists

Many researchers have surveyed damages caused by natural enemies of invasive plants in both native and introduced ranges to test the enemy release hypothesis. In this study, we report our findings on the physiological and morphological impacts of a co-evolved specialist insect (Agasicles hygrophila) and two generalist insects (Atractomorpha sinensis and Hymenia recurvalis) in introduced ranges on an invasive plant, Alternanthera philoxeroides, in both field trials and controlled environments. The resistance of A. philoxeroides against the generalists and the specialist was also studied. We obtained consistent results in both the field trials and the controlled treatments: both the generalists and the specialist decreased leaf biomass, photosynthesis, leaf nitrogen content, and total leaf non-structural carbohydrate content in A. philoxeroides. However, the specialist decreased leaf mass, photosynthesis, and leaf nitrogen content more acutely than the generalists. Moreover, A. philoxeroides increased both leaf lignin and cellulose concentrations upon the generalists’ attack but only increased cellulose concentration in response to the specialist. Our results showed that even under the same population density, the co-evolved specialists from original ranges caused more severe morphological and physiological damage to A. philoxeroides than the generalists in introduced ranges. This revealed that invasive plants released some herbivory stress before their co-evolved specialists were introduced, which may contribute to the superior performance of invasive plants in introduced regions.

Differences in Physiological Traits and Resistances of Alternanthera philoxeroides after Herbivory by Generalists and Specialists

Many researchers have surveyed damages caused by natural enemies in invasive plants in both native and introduced ranges to testing enemy release hypothesis. Although the physiological impact of natural enemies on invasive plants is important, little research has been conducted to compare the impacts between generalists and specialists. In this study, we report our findings on the physiological and morphological impacts of a native specialist insect (Agasicles hygrophila) and two generalist insects (Atractomorpha sinensis and Hymenia recurvalis) in introduced ranges on an invasive plants Alternanthera philoxeroides in both field trials and controlled environments. Resistances of A. philoxeroides against the generalists and the specialist were also studied. We obtained consistent results in both the field trials and the controlled treatments. Both the generalists and the specialist decreased leaf biomass, photosynthesis, leaf nitrogen content and total leaf non-structural carbohydrate content in A. philoxeroides. However, the specialist decreased leaf mass, photosynthesis, and leaf nitrogen content more acutely than the generalists. Moreover, A. philoxeroides increased both leaf lignin and cellulose concentrations upon the generalists’ attack, but only increased cellulose concentration in response to the specialist. Our results revealed that even under the same population density, the specialists from native ranges caused more severe morphological and physiological damages on A. philoxeroides than the generalists in introduced ranges. Which magnified the consequence of invasive plants suffered lower richness and abundance of natural enemy and contributed to superior performance of invasive plants in introduced regions.

Fungal treatment of lignocellulosic biomass: Importance of fungal species, colonization and time on chemical composition and in vitro rumen degradability

The aim of this study is to evaluate fungal treatments to improve in vitro rumen degradability of lignocellulosic biomass. In this study four selective lignin degrading fungi, Ganoderma lucidum, Lentinula edodes, Pleurotus eryngii and Pleurotus ostreatus, were used to pre-treat lignocellulosic biomass and to make the carbohydrates in the lignocellulose available for rumen microbes. Wheat straw, miscanthus, wood chips and rice straw were used as models for lignocellulosic biomass. Samples obtained after 12wks of incubation were assessed for fungal growth, in vitro gas production (IVGP72) as measure of rumen fermentation capacity and fibre composition. Most effects on IVGP72 and lignin degradation were found after 12wks of fungal treatment. Twelve weeks of treatment with L. edodes improved the IVGP72 of wheat straw by 58.5ml/g OM (23.1% increase), of miscanthus by 80.5ml/g OM (43.7% increase) and of wood chips by 123.4ml/g OM (229% increase). All fungi improved the IVGP72 of wood chips. Although all fungi grew on rice straw, the IVGP72 was not improved. All four fungal species caused increased cellulose concentration of wheat straw, miscanthus and wood chips. However, when expressed as absolute amounts, cellulose degradation occurred. In wheat straw and miscanthus, lignin was degraded best by L. edodes. Improvement of IVGP72 by L. edodes was correlated to lignin degradation. Lignin degradation and dry matter loss were correlated to the mycelium growth of L. edodes. These correlations differed between substrates and fungi. Fungal growth was not always a good predictor for the performance of the fungus. Here, L. edodes performed best, regarding IVGP72 and selective lignin degradation.

Effects of dietary cellulose on the Basal endogenous loss of phosphorus in growing pigs.

An experiment was conducted to determine the effect of cellulose concentration in diets containing no phosphorus (P) on the basal endogenous loss (BEL) of P in growing pigs. Twelve barrows (an initial mean body weight = 49.6±3.2 kg) were individually housed in metabolism crates. Pigs were allotted to 4 experimental diets according to a cross-over design with 12 animals and 2 periods. Four P-free diets were mainly based on corn starch, sucrose, and gelatin, and were formulated to contain 0%, 4%, 8%, or 12% cellulose. Each period consisted of a 5-d adaptation and a 5-d collection period. The marker-to-marker method was used for fecal collection. The feed intake (p<0.05, linear and quadratic) and dry feces output (p<0.01, linear and quadratic) were increased with increasing dietary cellulose concentration. However, P concentration in the feces was decreased (p<0.01, linear and quadratic) with increasing dietary cellulose concentration. There was no significant difference in total P output and the BEL of P as mg per kg DMI (ranging from 157 to 214 mg/kg of dry matter intake) among experimental diets. However, values for the apparent total tract digestibility of energy, dry matter, organic matter, crude protein, and calcium were linearly decreased (p<0.01) with increasing cellulose concentration in the diet. In conclusion, dietary cellulose affected the amount of feces and digestibility of energy and nutrients, but did not affect the endogenous loss of P.

The Synthesis of a Novel Cellulose Physical Gel

Cellulose possessing β‐cyclodextrin (β‐CD) was used as a host molecule and cellulose possessing ferrocene (Fc) as a guest polymer. Infrared spectra, differential scanning calorimetry (DSC), ultraviolet spectroscopy (UV), and contact angle analysis were used to characterise the material structure and the inclusion behaviour. The results showed that the β‐CD‐cellulose and the Fc‐cellulose can form inclusion complexes. Moreover, ferrocene oxidation, and reduction of state can be adjusted by sodium hypochlorite (NaClO) as an oxidant and glutathione (GSH) as a reductant. In this study, a physical gel based on β‐CD‐cellulose/Fc‐cellulose was formed under mild conditions in which autonomous healing between cut surfaces occurred after 24 hours. The physical gel can be controlled in the sol‐gel transition. The compressive strength of the Fc‐cellulose/β‐CD‐cellulose gel increased with increased cellulose concentration. The host‐guest interaction between the side chains of cellulose could strengthen the gel. The cellulose physical gel may eventually be used as a stimulus‐responsive, healing material in biomedical applications.

Impacts of Improved Switchgrass and Big Bluestem Selections on Yield, Morphological Characteristics, and Biomass Quality

Switchgrass (Panicum virgatumL.) and big bluestem (Andropogon gerardiiV.) are promising warm-season grasses for biomass production. Understanding the morphological and quality-related traits of these grasses can guide breeders in developing strategies to improve yield and quality for bioindustrial applications. Elite selections were made in Southern Quebec from four promising varieties of switchgrass and one of big bluestem. Biomass yield, morphological characteristics, and selected quality traits were evaluated at two sites in 2011 and 2012. Significant variation was detected for all measured characteristics, with differences varying by site and year. In some cases the selection process modified characteristics including increasing height and reducing tiller mortality. Switchgrasses reached a similar tiller equilibrium density in both years of 690 m−2and 379 m−2at a productive and marginal site, respectively. Differences in yield were pronounced at the marginal site, with some advanced selections having a higher yield than their parent varieties. Switchgrass yields were generally greater than those of big bluestem. A delayed spring harvest date greatly reduced yield but reduced moisture content and slightly increased cellulose concentration. Big bluestem had a higher cellulose content than switchgrass, likely due to greater stem content.

Cellulose/CaCO3 nanocomposites: Microwave ionic liquid synthesis, characterization, and biological activity

The purposes of this article are to synthesize the biomass-based hybrid nanocomposites using green method in green solvent and evaluate its biological activity. In this paper, microwave-assisted ionic liquid method is applied to the preparation of cellulose/CaCO3 hybrid nanocomposites in the alkali extraction cellulose using CaCl2 and Na2CO3 as starting reactants. The ionic liquid acts as the excellent solvent for absorbing microwave and the dissolution of cellulose, and the synthesis of cellulose/CaCO3 nanocomposites. The influences of reaction parameters such as the cellulose concentration and the types of solvent on the products were investigated. The increasing cellulose concentration favored the growth of CaCO3. The morphologies of CaCO3 changed from polyhedral to cube to particle with increasing cellulose concentration. Moreover, the solvents had an effect on the shape and dispersion of CaCO3. Cytotoxicity experiments demonstrated that the cellulose/CaCO3 nanocomposites had good biocompatibility and could be a candidate for the biomedical applications.

Investigation on Metastable Solution of Cellulose Dissolved in NaOH/Urea Aqueous System at Low Temperature

Our previous work has demonstrated that the cellulose solution dissolved in 7 wt % NaOH/12 wt % urea aqueous system precooled to -12 °C was metastable. It is worth noting that light scattering investigation on the cellulose solution at metastable state is difficult. In the present paper, the solution properties and dynamic behaviors of cellulose dissolved in the NaOH/urea aqueous solution were investigated by means of dynamic light scattering (DLS), to confirm the influence factors of the DLS measurement. The DLS results revealed that, after the dispersion of cellulose in NaOH/urea at low temperature, the single cellulose inclusion complexes (ICs) coexisted with minor IC aggregates even in very dilute solution. With increasing cellulose concentration or system temperature or prolonging storage time, the IC aggregation increased, as a result of the occurrence of the imperfect urea shell and the reconstruction of the hydrogen bonds between cellulose chains. The cellulose solution was relatively stable at low concentration and low storage temperature and for short storage time. In this case, the single cellulose inclusion complexes were the predominant species, and coexisted with minor IC aggregates, which was better to be used to measure the cellulose solution with DLS.

Phase Transition and Rheological Behaviors of Concentrated Cellulose/Ionic Liquid Solutions

The phase transition and rheological behaviors of concentrated solutions of microcrystalline cellulose (MCC) in an ionic liquid of 1-allyl-3-methylimidazolium chloride (AMIMCl) have been investigated. Polarized optical microscopy (POM) measurements indicate that the two critical cellulose concentrations for the appearance of biphase and fully anisotropic phase for MCC/AMIMCl solutions are 9 and 16 wt%, respectively. POM and differential scanning calorimetry (DSC) measurements coherently indicate that the clearing temperature, T(c) increases with increasing cellulose concentration. Oscillatory shear measurements show that the crossover frequency first moves to lower values and then moves back to higher values with increasing cellulose concentration, which indicates that most cellulose chains are aligned or oriented to reduce chain entanglements when the cellulose concentration is above 14 wt%. From the steady shear measurements, it is surprising to find that the viscosity versus shear rate curves exhibit four flow regions including two plateaus and two shear-thinning regions when the cellulose concentration exceeds 9 wt%. The influences of cellulose concentration and temperature on the first normal stress differences (N(1)) are analyzed according to the Larson theory. The peak of N(1) always appears at the intermediate part of the first shear-thinning region, and the following minimum of N(1) appears at the onset of the second shear-thinning region. The viscosity versus shear rate curves only exhibit two flow regions when temperature is above the respective T(c); meanwhile, negative N(1) values disappear and N(1) increases monotonically. The above results suggest that melting of the liquid crystal domains at high temperature results in the disappearance of the second plateau for the viscosity versus shear rate curves.

Ionic Liquids in the Preparation of Biopolymer Composite Materials

Preliminary data are shown for the mechanical properties of cellulose and silk composite blends with and without nanomodifiers. Composite strength increases with increasing cellulose concentration for samples created with two different coagulation solutions. In general, samples containing > 30% silk are difficult to handle and test because they are extremely brittle. The addition of nanocomposites may increase overall strength of samples, but is dependent on the morphology of the nanomaterial added.

Inverse gas chromatography for determining the dispersive surface free energy and acid–base interactions of sheet molding compound—Part II 14 Ligno‐cellulosic fiber types for possible composite reinforcement

AbstractComposites reinforced with natural plant fibers are currently actively researched. Inverse gas chromatography (IGC) is a technique that is used to characterize the surface energy and polar characteristics of materials. The theoretical approaches used with IGC are reviewed and applied to the study of 14 ligno‐cellulosic fiber types including grass fibers, bast fibers, leaf fibers, seed fibers, and fruit fibers. This was done to provide insight into the impact of fiber composition on the surface characteristics of the different fiber types and explore possible correlations among the data. The dispersive surface energy, and Ka, Kb constants are reported for the 14 fiber types and compared with values reported in the literature. The dispersive energies ranged from 35.5 mJ/m2 to 44.2 mJ/m2 at 20°C with Ka from 0.01 to 0.38 and Kb from 0 to 1.05. A correlation was found at 40°C for surface energy related to fiber composition and fiber type where the surface energy decreases with increasing lignin and hemicellulose composition but increased with increasing cellulose concentration. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008