Viscosity Of Cellulose Research Articles

Nanofabrication of Losartan Potassium Sustained Release Floating Microspheres using Different Grades of Ethyl Cellulose and its Insight on Release Profiles.

A sustained release system for losartan potassium designed to delay its residence time in the stomach through the preparation of solvent evaporation technique-based floating microspheres. The influence of the different grades of Ethocel™ such as 4 cps, 10 cps, and 22 cps as well as the drug: polymer ratio on various properties of microspheres were tested. Thermal and functional analysis revealed no interaction between the encapsulated drug and polymer. The results indicated that the mean diameter of microspheres increased with a change in grades of ethyl cellulose relating to viscosity. However, the drug incorporation efficiency within ethyl cellulose microspheres decreased with increasing viscosity of ethyl cellulose. The bulk density of the formulations was proportionally dependent on concentration and the viscosity of the polymer, which resulted in a decrease in floating capacity from 90.02% to 73.58%. Moreover, the drug release was indirectly proportional to the viscosity of ethyl cellulose tested. The in vitro release profile exhibited a burst effect with a biphasic release pattern following Fickian diffusion, indicating a diffusioncontrolled release mechanism. The results demonstrated that the viscosity of ethyl cellulose significantly affects the floating capacity and drug release pattern from microspheres.

Influence of cellulose viscosity on the physical, mechanical, and barrier properties of the chitosan-based films

This research paper presents a comprehensive investigation into developing biodegradable films for food packaging applications using chitosan (CN) in conjunction with three distinct types of cellulose (CE), each characterized by varying viscosities. The primary objective was to assess the influence of cellulose viscosity on the physical, mechanical, and barrier properties of the resulting films. The medium-viscosity cellulose imparted numerous advantageous qualities to the biodegradable films. These films exhibited optimal thickness (31 μm), ensuring versatility in food packaging while maintaining favorable mechanical properties, blending strength, and flexibility. Also, medium-viscosity cellulose significantly improved the films' barrier performance, particularly regarding oxygen permeability [1.80 × 10−6 (g.mm.m−2. s−1)]. Furthermore, the medium-viscosity cellulose contributed to superior moisture-related properties, including reduced water vapor permeability [14.80 × 10−9 (g.mm.m−2. s−1. Pa−1)], moisture content (13.22 %), and water solubility (22.87 %), while maintaining an appropriate degree of swelling (41.88 %). Moreover, the study employed advanced analytical techniques, including FTIR, XRD, and TGA, to provide critical insights into the films' chemical, structural, and thermal aspects. This research underscored the importance of the viscosity of film formulation materials as a crucial element in designing and efficiently producing films for food packaging.

Innovation in Green Materials for the Non-Contact Stabilization of Sensitive Works of Art: Preliminary Assessment and the First Application of Ultra-Low Viscosity Hydroxypropyl Methylcellulose (HPMC) by Ultrasonic Misting to Consolidate Unstable Porous and Powdery Media

Paintings and other works of art created with fragile and mechanically unstable powdery media present challenges to conservators. Frequently, powdery media is water-sensitive, extremely fragile, tends to delaminate, and may be altered by even the slightest physical action or interaction with liquids. Materials that can provide an efficient stabilization without unacceptably altering the optical characteristics of the delicate substrate are extremely limited. Among these, Funori, Isinglass, and Methocel A4C have become established for this use. In bench practice, consolidants are frequently applied in a non-contact way, using ultrasonic and pneumatic aerosol generators to minimize the impact of the consolidant on sensitive substrates. However, nebulizing the available materials is problematic in bench practice, because of their high viscosity and, only extremely low concentrations can be nebulized using low kinetic impact ultrasonic or pressure-based misting systems adopted from the healthcare industry. As a potential innovative solution, this study introduces novel ultra-low viscosity (ULV) cellulose ethers (ULV-HPMC) for stabilisation of unstable porous and powdery surfaces, which have been successfully applied in bench practice for the pilot treatment of Edvard Munch painting on canvas and two 19th c. Thai gouache paintings on panel. Novel ULV-HPMC materials have multiple desirable qualities for consolidation treatments in conservation, and in accelerated aging tests marginally outperformed Methocel A4C, considered to be one of the most stable consolidants in the practice of conservation. Because of the ultra-low viscosity, higher concentrations of ULV-HPMC materials can be applied as water-based aerosols in a non-contact way and in fewer applications, which is a significant advantage in the treatment of delicate water-sensitive surfaces. Notably, novel ULV biopolymers are low-cost, derive from sustainable and renewable sources, and do not raise health and environmental concerns. Such novel materials and methods seamlessly resonate with the ICOM-CC’s Melbourne 2014 declaration, EU Green Deal, and the UN’s Sustainable Development goals and show potential adding new sustainable materials with the exceptionally low viscosity to the conservator’s tool box.

Temperature‐Sensitive Properties and Mechanism of Smart Magnetic Fluids Modified with Cellulose Derivatives

AbstractCombining magnetic materials with environmentally sensitive polymers to develop intelligent magnetic fluids that respond to external stimuli has become a new research hotspot. At present, the bottlenecks in the development of temperature‐sensitive materials are the complex composition, and its properties in different laboratories vary greatly. Moreover, despite extensive research on magnetic fluids, there remains a dearth of systematic investigation into temperature‐sensitive intelligent magnetic fluids. In this study, we utilized a UV‐visible spectrophotometer to measure the change in transmittance of different magnetic fluid solutions with temperature variation. We systematically investigated the effects of the magnetic fluid dispersion medium, size and concentration of magnetic nanoparticles, type and viscosity of cellulose on the temperature sensitivity of the magnetic fluid. We found that compared with Hydroxypropyl Methyl Cellulose (HPMC) (type I), HPMC (type II) modified magnetic fluid has better stability and a higher phase transition temperature. Moreover, with the increase of the concentration of magnetic fluid, the phase transition temperature is higher. In addition, the lower the viscosity of HPMC‐modified magnetic fluid, the better the stability and the higher the phase transition temperature. We also studied the mechanism of temperature sensitivity, and the results showed that hydrogen bond interactions play an important role. This research will facilitate the use of temperature‐sensitive smart magnetic fluids for biomedical application.

Chemical Recycling of a Textile Blend from Polyester and Viscose, Part I: Process Description, Characterization, and Utilization of the Recycled Cellulose

Material recycling requires solutions that are technically, as well as economically and ecologically, viable. In this work, the technical feasibility to separate textile blends of viscose and polyester using alkaline hydrolysis is demonstrated. Polyester is depolymerized into the monomer terephthalic acid at high yields, while viscose is recovered in a polymeric form. After the alkaline treatment, the intrinsic viscosity of cellulose is decreased by up to 35%, which means it may not be suitable for conventional fiber-to-fiber recycling; however, it might be attractive in other technologies, such as emerging fiber processes, or as raw material for sugar platforms. Further, we present an upscaled industrial process layout, which is used to pinpoint the areas of the proposed process that require further optimization. The NaOH economy is identified as the key to an economically viable process, and several recommendations are given to decrease the consumption of NaOH. To further enhance the ecological end economic feasibility of the process, an increased hydrolysis rate and integration with a pulp mill are suggested.

Modification of waste persimmon peel and application in water-based drilling fluid

To develop a green drilling fluid additive, the modification and application of persimmon peel in a water-based drilling fluid was studied in this work. A natural product derivative, aluminium chloride–persimmon peel (ACPP), was prepared from aluminium chloride and persimmon peel and was assessed as a shale inhibitor. The clay-swelling ratio in 0.30% ACPP-3 solution was reduced to 28.10% from 69.50%. The rolling recovery tests and rheological evaluation of drilling fluids concluded that ACPP-3 has a high inhibition property to montmorillonite-hydrated expansion. ACPP-3 can adjust the particle size of montmorillonite to a large degree. ACPP-3 effectively reduces the apparent viscosity of carboxymethyl cellulose drilling fluids and the volume of filtration; furthermore, ACPP-3 can reduce the viscosity and the volume of filtration under high temperature, which means it can be used as an additive for deep drilling. The inhibition mechanism of ACPP-3 was investigated by thermogravimetric analysis and scanning electron microscopy. The results of this scientific research will be beneficial to the eco-friendly drilling fluid materials.

Improving cellulose viscosity protection and delignification in ozone bleaching of low-consistency pulp with water-soluble chitosan

The effect of water-soluble chitosan (WSC) with molecular weights (Mw) from 1.0×104 to 1.0×106 on cellulose viscosity protection was explored during the treatment of low-consistency pulp with the ozone bleaching process (OBP). Through determination of the change in crystallinity, carboxyl content, and physical strength of ozone-bleached refined dissolving pulp, WSC was shown to effectively protect cellulose viscosity by scavenging free radicals and forming a protective film deposited on the fiber surface to prevent the destruction of cellulose by oxidants. During the OBP of sulfate hardwood pulp (SHP), application of a 0.5 % dose of WSC with a Mw of 1.0×105 increased not only the cellulose viscosity but also the selectivity of ozone delignification. The brightness, viscosity, and delignification selectivity of the bleached SHP were enhanced by 3.88±0.05 %, 13.0±0.10 %, and 76.6±0.50 %, respectively. Accordingly, the indexes of tensile strength, burst strength and tear strength of the resulting SHP hand sheet were increased by 38.6±1.0 %, 74.8±1.5 %, and 117.3±2.5 %, respectively. WSC had the best performance among the reported additives of equal weights for protection of cellulose viscosity in improving the pulp qualities after the OBP.

Experimental Investigations on Stability and Viscosity of Carboxymethyl Cellulose (CMC)-Based Non-Newtonian Nanofluids with Different Nanoparticles with the Combination of Distilled Water

Experimental Investigations on Stability and Viscosity of Carboxymethyl Cellulose (CMC)-Based Non-Newtonian Nanofluids with Different Nanoparticles with the Combination of Distilled Water

Temperature and Concentration Dependent Viscosity of Microcrystalline Cellulose in Water

The viscosity of cellulose behaves differently and uniquely in various conditions. In this paper, we aim to report the viscosity measurement and related properties of low concentration of microcrystalline cellulose (MCC) in water using a magnetic bearing rheometer. Dynamic viscosities for MCC diluted in water at varying concentrations were measured using the standard rheometry technique. The viscosity of the MCC solution was found highly dependent on its concentration and the experiment temperature. This varieties behaviour and properties offers benefits to the current growing rapidly technology applications such as in food, pharmaceutical cosmetics and textile.

Viscosity of Aqueous Polysaccharide Solutions and Selected Homogeneous Binary Mixtures

The viscosity (η) of dextran (Dex), methyl cellulose (MC), hydroxypropylmethyl cellulose (HPMC), κ-carrageenan (KC), alginate (Alg), and carboxymethyl cellulose (CMC) was measured as a function of the shear rate (γ̇) over a broad range of concentrations both in salt-free water and in 0.1 M NaCl. The concentration (C) dependence of the Newtonian viscosity (η0) was found to be universal for neutral polysaccharides and anionic polysaccharides in 0.1 M NaCl when C was multiplied with the intrinsic viscosity. The dependence was compared with theoretical predictions assuming dominant hydrodynamic or dominant topological interactions. The effect of electrostatic interactions was observed for anionic polysaccharides in salt-free water but not at higher concentrations. Master curves of the shear thinning behavior at different concentrations were obtained when η/η0 was plotted versus τ. γ̇, with τ being a concentration-dependent time that characterizes the onset of shear thinning. Binary mixtures of two neutral polysaccharides (MC and HPMC), two anionic polysaccharides (Alg and CMC), and a neutral (Dex) and anionic polysaccharide (KC) were investigated as a function of the composition and the total polysaccharide concentration. The behavior of the first two mixtures was similar to that of a single polysaccharide with an intermediate intrinsic viscosity. Significant synergy was observed for the third type of mixtures in salt-free water demonstrating the important effect of electrostatic interactions between charged polysaccharides at low concentrations even in concentrated solutions of neutral polysaccharides.

Ethyl cellulose particles loaded with α-tocopherol for inhibiting thermal oxidation of soybean oil

Most endogenous antioxidants degrade and lose efficiency during frying. The study aimed to inhibit thermal oxidation of soybean oil by fabricating α-tocopherol loaded particles with ethyl cellulose (EC) of different viscosity grades (M9, M70 and M200) via anti-solvent method. As the viscosity of ethyl cellulose increased, particle size decreased from micrometer to nanometer. Confocal laser scanning microscope confirmed successful encapsulation and uniform distribution of α-tocopherol in the loaded particles. Differential scanning calorimetry and thermogravimetric analysis demonstrated that loaded particles protected α-tocopherol from oxidation and degradation. Meanwhile, Fourier transformed infrared demonstrated that α-tocopherol interacted with EC through hydrogen bond and hydrophobic effects. With excellent dispersibility in soybean oil, loaded particles effectively inhibited thermal oxidation of soybean oil and loaded M200 nanoparticles was the most effective, which performed far better than tert-butylhydroquinone (TBHQ). Therefore, the nanoparticles offered a promising way to enhance oxidative stability of oils during thermal processing.

A study on the impact of HPMC viscosity grade and proportion on the functional properties of co-freeze-dried mannitol-HPMC cushioning excipients for compacted MUPS

The co-processing of multiple excipients is driven by the potential of diversifying the properties and functionality of excipients when they are combined. Bulk freeze-drying-milling is a novel secondary processing approach to develop co-processed excipients. It offers a significant advantage of formulation flexibility. This study was designed to systematically investigate the impact of 3 factors, hydroxylpropyl methyl cellulose (HPMC) viscosity grade, mannitol to HPMC ratio and particle size fraction on the functional properties of freeze-dried (FD) mannitol-HPMC cushioning excipients produced for multi-unit pellet system tableting. Based on the results, the investigated formulation variables were significant in determining the functional properties of the FD-mannitol-HPMC cushioning excipients. Among the formulations, FD-mannitol-HPMC F4M (3:1 ratio) excipients exhibited the best cushioning performance. It was postulated that the protective effects of the cushioning excipient were brought about by its propensity for rearrangement around the coated pellets to reduce detrimental pellet-pellet contact and ability to absorb damaging compressive forces. Conversely, FD-mannitol-HPMC vLV (3:1 ratio) had cushioning effects but showed short disintegration time while maintaining adequate tablet tensile strength. Overall, the results of this study highlighted the impact of formulation variables on the functional properties of the cushioning excipients, arising from an interplay of the freeze-dried particle properties.

Improvement on Measuring the Intrinsic Viscosity of Cellulose by the Copper Ethylenediamine Method

Improvement on Measuring the Intrinsic Viscosity of Cellulose by the Copper Ethylenediamine Method

Dissolution of cellulose using a combination of hydroxide bases in aqueous solution

In order to further understand the role of the cation when dissolving cellulose in aqueous solutions of hydroxide bases, different bases were combined in solution. Up to 5 wt.% of microcrystalline cellulose was dissolved using a combination of NaOH and the organic base tetramethylammonium hydroxide (TMAH) in water at low temperatures. Thermoscans of solutions containing both NaOH(aq) and TMAH(aq) indicated that cellulose interaction with TMAH seems to be favoured over NaOH. Dynamic rheology measurements of the solutions revealed that combining the two bases delayed gelation significantly when compared to cellulose dissolved in NaOH(aq) or TMAH(aq) alone. Intrinsic viscosity of cellulose in the combined NaOH- and TMAH(aq) solutions was slightly higher than that of the single-base solutions, indicating a slight increase in solvent quality. This shows that combining bases may lead to synergies that improve solvent stability without requiring the use of other additives.Graphic abstract

Elucidation of the Relationship between Intrinsic Viscosity and Molecular Weight of Cellulose Dissolved in Tetra-N-Butyl Ammonium Hydroxide/Dimethyl Sulfoxide.

The determination of molecular weight of natural cellulose remains a challenge nowadays, due to the difficulty in dissolving cellulose. In this work, tetra-n-butylammonium hydroxide (TBAH) and dimethyl sulfoxide (DMSO) aqueous solution (THDS) were used to dissolve cellulose in a few minutes under room temperature into true molecular solutions. That is to say, the cellulose was dissolved in the solution in molecular level, and the viscosity of the solution is linearly dependent on the concentration of cellulose. The relationship between the molecular weight of cellulose and the intrinsic viscosity tested in such dilute solutions has been established in the form of the Mark–Houwink equation, . The value of 1.21 indicates that the cellulose molecules dissolve in THDS quite well. The cellulose dispersion in the THDS was proved to be in molecular level by atomic force microscope (AFM) and dynamic light scattering (DLS). The reliability of the established Mark–Houwink equation was cross-checked by the gel permeation chromatography (GPC) and traditional copper (II) ethylenediamine (CED) method. No considerate degradation was observed by comparing the intrinsic viscosity and the degree of polymerization (DP) values of the original with and the regenerated cellulose samples. The natural cellulose can be molecularly dispersed in the multiple-component solvent (THDS), and kept stable for a certain period. A time efficient and reliable method has been supplied for determination of the degree of polymerization and the molecular weight of cellulose.

Viscometric behavior of hydroxyethyl cellulose in aqueous solutions of some imidazolium ionic liquids

In this work, viscosity of hydroxyethyl cellulose in aqueous solutions of ionic liquids, 1-butyl-3-methyl imidazolium bromide, 1-hexyl-3-methyl imidazolium bromide and 1-octyl-3-methyl imidazolium bromide were measured at temperature range of T = 288.15–308.15 K. Some hydrodynamic and thermodynamic parameters such as intrinsic viscosity, polymer–solvent interaction parameter and second virial coefficient were calculated using viscosity data. Obtained results reveal that thermodynamic quality of aqueous solutions of ionic liquids for hydroxyethyl cellulose decreases with increasing temperature and addition of ionic liquids. The flow activation energy was found from the linearization of Arrhenius equation and correlated in terms of polymer concentration. From sign of the initial slope of the activation energy versus polymer concentration at zero concentration, it is concluded that thermodynamic quality of aqueous solutions of ionic liquids are reduced by increasing temperature.

An effective metal controller used for enhancing cellulose protection in oxygen delignification

Due to the detrimental effects induced by transition metals on oxygen delignification, it is necessary to explore effective cellulose protector for improving the oxygen delignification efficiency. In this work, chitosan/tripolyphosphate microspheres (C/TPP) with different size were prepared and introduced for alleviating the transition metal ions effects on cellulose degradation. The results showed that both size and amount of C/TPP had a significant effect on cellulose degradation but negligible influence on lignin; C/TPP with suitable amount and smaller size was favored for cellulose protection and thus selectivity improvement. C/TPP is found to be comparable to MgSO4 and more outstanding for the pulps with extra metals; in this case, C/TPP leads only a marginal impairment in lignin degradation and removal, but provides a significant improvement for cellulose viscosity. Moreover, C/TPP is substantially more effective when is used in a combination with MgSO4.

The Effect of Additives on the Viscosity and Dissolution of Cellulose in Tetrabutylphosphonium Hydroxide.

An electrolyte solution of tetrabutylphosphonium hydroxide (TBPH) in water can dissolve over 20 wt % of cellulose in minutes and therefore constitutes a promising alternative green solvent system compared to known imidazolium- or dimethylacetamide-based systems. Overcoming the disadvantage of the extremely high viscosity of TBPH/cellulose solutions can facilitate their use for various applications. In this study, the application of cosolvents for the reduction, and thus adjustability, of the viscosity is addressed. Even well-known antisolvents can be easily deployed, resulting in a dramatic drop in viscosity. High concentrations of cosolvents (excluding ethanol) are tolerated without precipitation of the dissolved cellulose. Furthermore, the effect of the cosolvents on the additional dissolution of cellulose is discussed. The amount of dissolved cellulose is quantified by 13 C NMR spectroscopy.

Fabrication and physicochemical and antibacterial properties of ethyl cellulose-structured cinnamon oil oleogel: relation between ethyl cellulose viscosity and oleogel performance.

Edible packaging and coating with natural antimicrobials such as essential oils is an emerging technology for the control of pathogen growth in meat products. This study aimed to explore ethyl cellulose (EC) of three viscosities for the structuring of cinnamon essential oil (CEO), and investigated the physicochemical properties of the resulting oleogel and its emulsion, as well as the corresponding antibacterial activity in model and actual environments (as in sausages). The network structure of CEO-EC oleogel was more compact with increased EC viscosity, thereby improving the binding capacity and stability of the oil. A positive correlation was found between EC viscosity and particle size of the CEO-EC emulsion. The 45 cP CEO-EC emulsion exhibited greatest antimicrobial activitiy in models with Escherichia coli (E. coli) O157:H7 (ATCC 700927) and Staphylococcus aureus (S. aureus) (ATCC 29213), as well as in sausage, with respect to total counts of mesophilic bacteria, psychrotrophs, lactobacilli, and pseudomonads. The CEO-EC oleogel has antibacterial activity, determined by the EC viscosity, that provide potential antibacterial protection for meat products and might be especially suitable for some traditional Chinese ready-to-eat sausages without strictly sealed packaging. © 2019 Society of Chemical Industry.

Influence of Cellulose Ethers on the Consistency, Water Retention and Adhesion of Renovating Plasters

Cellulose ethers such as (hydroxypropyl)methyl cellulose (HPMC), (hydroxyethyl)methyl cellulose (HEMC), methyl ethyl hydroxyethyl cellulose (MEHEC) are currently used admixtures in the production of factory-made mortars. They improve such properties as water retention, workability, adhesion to the substrate, open time etc. in the cement-based mortars. The article investigates the impact of physicochemical properties (molecular weight, methods of modification, viscosity) on water retention, rheological properties and the adhesiveness to the substrates of renovation plasters. The research showed that the cellulose viscosity has a greater impact on water retention despite diversified effects of various derivatives of cellulose. The influence of viscosity of cellulose ethers is uneven. The greatest growth of retention was observed with the change of viscosity from 100 mPa⋅s to 15000 mPa⋅s. The further growth of viscosity of cellulose admixtures influenced the change of water retention with lower intensity. It was also stated that cellulose ethers improve the adhesion of renovation plasters to the substrates. Particularly beneficial results were obtained in the case of plasters consisting (hydroxypropyl)methyl cellulose(HPMC)-based admixtures.