Cellulose-based Polymers Research Articles

Customising Sustainable Bio-Based Polyelectrolytes: Introduction of Charged and Hydrophobic Groups in Cellulose

Cellulose has been widely explored as a sustainable alternative to synthetic polymers in industrial applications, thanks to its advantageous properties. The introduction of chemical modifications on cellulose structure, focusing on cationic and hydrophobic modifications, can enhance its functionality and expand the range of applications. In the present work, cationization was carried out through a two-step process involving sodium periodate oxidation followed by a reaction with the Girard T reagent, yielding a degree of substitution for cationic groups (DScationic) between 0.3 and 1.8. Hydrophobic modification was achieved via esterification with fatty acids derived from commercial plant oils, using an enzyme-assisted, environmentally friendly method. Lipase-catalysed hydrolysis, optimised at 0.25% enzyme concentration and with a 1 h reaction time, produced an 84% yield of fatty acids, confirmed by FTIR and NMR analyses. The degree of substitution for hydrophobic groups (DShydrophobic) ranged from 0.09 to 0.66. The molecular weight (MW) of the modified cellulose derivatives varied from 1.8 to 141 kDa. This dual modification strategy enables the creation of cellulose-based polymers with controlled electrostatic and hydrophobic characteristics, customisable for specific industrial applications. Our approach presents a sustainable and flexible solution for developing cellulose derivatives tailored to diverse industrial needs.

Amorphous Solid Dispersion Formation for Enhanced Release Performance of Racemic and Enantiopure Praziquantel.

Praziquantel (PZQ) is the treatment of choice for schistosomiasis, which affects more than 250 million people globally. Commercial tablets contain the crystalline racemic compound (RS-PZQ) which limits drug dissolution and oral bioavailability and can lead to unwanted side effects and poor patient compliance due to the presence of the S-enantiomer. While many approaches have been explored for improving PZQ's dissolution and oral bioavailability, studies focusing on investigating its release from amorphous solid dispersions (ASDs) have been limited. In this work, nucleation induction time experiments were performed to identify suitable polymers for preparing ASDs using RS-PZQ and R-PZQ, the therapeutically active enantiomer. Cellulose-based polymers, hydroxypropyl methylcellulose acetate succinate (HPMCAS, MF grade) and hydroxypropyl methylcellulose (HPMC, E5 LV grade), were the best crystallization inhibitors for RS-PZQ in aqueous media and were selected for ASD preparation using solvent evaporation (SE) and hot-melt extrusion (HME). ASDs prepared experimentally were subjected to X-ray powder diffraction to verify their amorphous nature and a selected number of ASDs were monitored and found to remain physically stable following several months of storage under accelerated-stability testing conditions. SE HPMCAS-MF ASDs of RS-PZQ and R-PZQ showed faster release than HPMC E5 LV ASDs and maintained good performance with an increase in drug loading (DL). HME ASDs of RS-PZQ formulated using HPMCAS-MF exhibited slightly enhanced release compared to that of SE ASDs. SE HPMCAS-MF ASDs showed a maximum release increase of the order of 6 times compared to generic and branded (Biltricide) PZQ tablets. More importantly, SE R-PZQ ASDs with HPMCAS-MF released the drug as effectively as RS-PZQ or better, depending on the DL used. These findings have significant implications for the development of commercial PZQ formulations comprised solely of the R-enantiomer, which can result in mitigation of the biopharmaceutical and compliance issues associated with current commercial tablets.

High-performance cellulose-based nanostructured carbons for rechargeable batteries

Binder-free, highly porous carbon nanofibers (CNFs) with novel sponge-like pore structures were synthesized for the first time via centrifugal spinning of cellulose-based polymers, and SnO2 was introduced to improve the electrochemical performance. Cellulose-based binder-free centrifugally spun carbon-coated SnO2/carbon nanofibers (C@SnO2/CNFs) were employed as anodes in Na-ion batteries. Owing to their highly porous morphology with novel sponge-like pore structures and SnO2 nanoparticles providing rapid Na-ion transport, better electrolyte accessibility, and good mechanical strength, the C@SnO2/CNFs showed outstanding electrochemical performance, with a high reversible capacity of 660 mAh/g at 50 mA/g, high rate capability, and excellent cycling performance. The specific capacity of C@SnO2/CNFs was approximately 390 mAh/g after 2000 cycles at 0.2 A/g. These results prove that the combination of centrifugal spinning, carbon coating, and heat treatment is a promising and sustainable approach for creating cellulose-based carbon nanostructures with highly porous structures that can be used to synthesize high-performance electrodes for energy storage systems.

Green Synthesis of Bioplastics from Microalgae: A State-of-the-Art Review.

The synthesis of conventional plastics has increased tremendously in the last decades due to rapid industrialization, population growth, and advancement in the use of modern technologies. However, overuse of these fossil fuel-based plastics has resulted in serious environmental and health hazards by causing pollution, global warming, etc. Therefore, the use of microalgae as a feedstock is a promising, green, and sustainable approach for the production of biobased plastics. Various biopolymers, such as polyhydroxybutyrate, polyurethane, polylactic acid, cellulose-based polymers, starch-based polymers, and protein-based polymers, can be produced from different strains of microalgae under varying culture conditions. Different techniques, including genetic engineering, metabolic engineering, the use of photobioreactors, response surface methodology, and artificial intelligence, are used to alter and improve microalgae stocks for the commercial synthesis of bioplastics at lower costs. In comparison to conventional plastics, these biobased plastics are biodegradable, biocompatible, recyclable, non-toxic, eco-friendly, and sustainable, with robust mechanical and thermoplastic properties. In addition, the bioplastics are suitable for a plethora of applications in the agriculture, construction, healthcare, electrical and electronics, and packaging industries. Thus, this review focuses on techniques for the production of biopolymers and bioplastics from microalgae. In addition, it discusses innovative and efficient strategies for large-scale bioplastic production while also providing insights into the life cycle assessment, end-of-life, and applications of bioplastics. Furthermore, some challenges affecting industrial scale bioplastics production and recommendations for future research are provided.

Chemo- and enantioselective analysis of high hydrophilic organophosphate pesticides by liquid chromatography under different elution modes

Acephate and malathion are prevalent chiral organophosphate insecticides, giving rise to more toxic chiral metabolites such as methamidophos and malaoxon, respectively. Enantioselective separation of chiral pesticides is crucial due to the differing pharmacological, environmental, and toxicological profiles of enantiomers. This study systematically evaluates an enantio‑ and chemoselective performance of eight polysaccharide-based chiral columns (Chiralcel OB-H, Chiralcel OD-H, Chiralcel OJ-R, Chiralpak AD-H, Chiralpak AS-H, Chiralpak IG-3, Chiralpak IK-3, and Lux-Amylose-2) and ten mobile phases across multimodal elution (normal-phase, polar organic, and reversed-phase conditions). Within the 80 combinations per analyte, the chiral screening highlights specific enantioselectivity trends concerning hydrophilic and hydrophobic compounds when utilizing amylose- or cellulose-based polymers under different conditions. Notably, a set of columns including IK-3, OJ-R, AS-H, and AD-H demonstrated superior coverage, achieving at least a 62 % success rate for enantioseparation. For the resolution between the pairs acephate/methamidophos and malathion/malaoxon, where no further optimizations were undertaken, the success rate for enantio‑ and chemoselectivity was 10 % and 30 %, respectively.

The Effect of the Mixture of Natural and Cellulose-Based Polymers on the Physicochemical Properties of Sumatriptan Succinate Mucoadhesive Buccal Patches

The Effect of the Mixture of Natural and Cellulose-Based Polymers on the Physicochemical Properties of Sumatriptan Succinate Mucoadhesive Buccal Patches

Photocrosslinkable Cellulose Derivatives for the Manufacturing of All-Cellulose-Based Architectures.

Replacing petroleum-based polymers with biopolymers such as polysaccharides is essential for protecting our environment by saving fossil resources. A research field that can benefit from the application of more sustainable and renewable materials is photochemistry. Therefore, cellulose-based photoresists that could be photocrosslinked via UV irradiation (λ = 254 nm and λ = 365 nm) were developed. These biogenic polymers enable the manufacturing of sustainable coatings, even with imprinted microstructures, and cellulose-based bulk materials. Thus, herein, cellulose was functionalized with organic compounds containing carbon double bonds to introduce photocrosslinkable side groups directly onto the cellulose backbone. Therefore, unsaturated anhydrides such as methacrylic acid anhydride and unsaturated and polyunsaturated carboxylic acids such as linoleic acid were utilized. Additionally, these cellulose derivatives were modified with acetate or tosylate groups to generate cellulose-based polymers, which are soluble in organic solvents, making them suitable for multiple processing methods, such as casting, printing and coating. The photocurable resist was basically composed of the UV-crosslinkable biopolymer, an appropriate solvent and, if necessary, a photoinitiator. Moreover, these bio-based photoresists were UV-crosslinkable in the liquid and solid states after the removal of the solvent. Further, the manufactured cellulose-based architectures, even the bulk structures, could be entirely regenerated into pure cellulose devices via a sodium methoxide treatment.

Unraveling the Governing Mechanisms Behind the Chiral Nematic Self-Assembly of Cellulose-Based Polymers

Unraveling the Governing Mechanisms Behind the Chiral Nematic Self-Assembly of Cellulose-Based Polymers

Stable Surface Modification by Cold Atmospheric-Pressure Plasma: Comparative Study on Cellulose-Based and Synthetic Polymers.

This study's aim is a comparison of the plasma-induced effects on polymers exposed in helium and argon gaseous environments in a pulsed dielectric barrier discharge at atmospheric pressure. Cellulose-based and synthetic polymers are tested with regard to a range of parameters, such as wettability, adhesion, surface energy and polarity, the oxygen amount in their structure, and surface morphology. The surface properties are analyzed by contact angle measurements, X-ray photoelectron spectroscopy, and scanning electron microscopy images. The results point to the efficient and remarkably stable modifications of the plasma-exposed surfaces, such as their enhanced adhesion, surface energy, and oxygen incorporation. Additionally, plasma provides significant oxygen uptake in cellulose-based materials that bear already prior to treatment a high amount of oxygen in their structure. The comparison between the properties of the non-permeable, homogeneous, smooth-surface synthetic polymer and those of the loosely packed, porous, heterogeneous cellulose-based polymers points to the different rates of plasma-induced modification, whereby a progressive alteration of cellulosic surface properties over much larger ranges of exposure durations is noted. Present experimental conditions ensure mild treatments on such sensitive material, such as paper, and this is without alterations of the surface morphology and the physical degradation of the material over a large range of treatment duration.

Eco-Friendly Cellulose-Based Nonionic Antimicrobial Polymers with Excellent Biocompatibility, Nonleachability, and Polymer Miscibility.

This study aims to prepare natural biomass-based nonionic antimicrobial polymers with excellent biocompatibility, nonleachability, antimicrobial activity, and polymer miscibility. Two new cellulose-based nonionic antimicrobial polymers (MIPA and MICA) containing many terminal indole groups were synthesized using a sustainable one-pot method. The structures and properties of the nonionic antimicrobial polymers were characterized using nuclear magnetic resonance hydrogen spectroscopy (1H NMR), infrared spectroscopy (FTIR), wide-angle X-ray diffractometry (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), gel chromatography (GPC), and other analytical techniques. The results showed that microcrystalline cellulose (MCC) molecules combined with indole derivatives through an esterification reaction to produce MICA and MIPA. The crystallinity of the prepared MICA and MIPA molecules decreased after MCC modification; their morphological structure changed from short fibrous to granular and showed better thermal stability and solubility. The paper diffusion method showed that both nonionic polymers had good bactericidal effects against the two common pathogenic bacteria Escherichia coli (E. coli, inhibition zone diameters >22 mm) and Staphylococcus aureus (S. aureus, inhibition zone diameters >38 mm). Moreover, MICA and MIPA showed good miscibility with biodegradable poly(vinyl alcohol) (PVA), and the miscible cellulose-based composite films (PVA-MICA and PVA-MIPA) showed good phase compatibility, light transmission, thermal stability (maximum thermal decomposition temperature >300 °C), biocompatibility, biological cell activity (no cytotoxicity), nonleachability, antimicrobial activity, and mechanical properties (maximum fracture elongation at >390%).

Nitrate Uptake by Cellulose-Based Anion Exchange Polymers Derived from Wheat Straw

Nitrate contamination of ground water is a serious problem due to the intensive agricultural activities needed to feed the world’s growing population. While effective, drinking water treatment using commercial ion exchange polymers is often too expensive to be employed. At the same time, lignocellulosic waste from crop production—an abundant source of the renewable polymer cellulose—is often burned to clear fields. This results in not only adverse health outcomes, but also wastes a valuable resource. In this study, wheat straw was pretreated to extract cellulose, then selectively oxidized with periodate, crosslinked with an alkyl diamine (1,7-diaminoheptane or 1,10-diaminodecane), and functionalized with a quaternary ammonium compound ((2-aminoethyl)trimethyl ammonium chloride) to generate a cellulose-based anion exchange polymer. This polymer lowered aqueous nitrate concentrations to health-based drinking water standards. Unlike commercial ion exchange polymers, its synthesis did not require the use of toxic epichlorohydrin or flammable solvents. The pretreatment conditions did not significantly affect nitrate uptake, but the crosslinker chain length did, with polymers crosslinked with 1,10-diaminodecane showing no nitrate uptake. Agricultural-waste-based anion exchange polymers could accelerate progress toward the sustainable development goals by providing low-cost materials for nitrate removal from water.

Comparison Adsorption of Cd (II) onto Lignin and Polysaccharide-Based Polymers.

Given the predominantly negative impact of heavy metals on living organisms, the present study proposed to evaluate the adsorption performances under static conditions of Cd (II) from aqueous solutions on unmodified Sarkanda grass lignin compared to the adsorption performances of polysaccharide polymers chemically functionalized, obtained by synthesis and in their native state, but which, although effective, have a cost price that does not allow for large-scale expansion. To improve the retention of Cd (II) on this aromatic component of the biomass resulting from the processing of lignocellulosic materials, different experimental conditions (pH, concentration, dose and contact time) were followed. The Freundlich and Langmuir isotherms were used to describe the equilibrium conditions. Adsorption kinetics were assessed using the Lagergren I and Ho and McKay II kinetic models, furnishing informative insights into the process mechanism. Lignin adsorption capacity was also analyzed by performing biological tests on tomato seeds (Lypercosium esculentum), since heavy metals are known to be a stress factor for seeds by disturbing the osmotic equilibrium. Through the prism of the investigated parameters and under precisely established experimental conditions, unmodified Sarkanda grass lignin-an aromatic biopolymer-can be recommended as a promising adsorbent for the retention of Cd (II) from aqueous solutions, successfully replacing polysaccharide, especially cellulose-based polymers.

Preliminary study of microplastic in bottled drinking water

Microplastic is widely discussed and has become growing attention because of its negative impact on the environment and the well-being of living organisms. Some international studies have found microplastics in some foods and beverages, such as honey, beer, table salt, and drinking water. However, there are few accurate analytical techniques for identifying and analysing microplastics, especially in beverages and foods. This preliminary study investigates microplastics that might contaminate bottled drinking water, their physical properties, and their types of material. Five local brands of 120 ml bottled drinking water were used for this research, collected from a traditional market in South Tangerang. The samples were observed visually for microplastic’s presence, sizes, and shapes using a digital microscope. Furthermore, material identification using a Microscope - Fourier transform infra-red (μ-FTIR) was conducted to analyse the types of material present in the samples. The results show that all examined samples were contaminated, and the major pollutants were fibres with lengths between 0.042 and 3.668 mm. According to the material identification result using μ-FTIR, materials found in most samples are cellulose-based polymers, which are used widely for natural textiles (e.g., cotton) and synthetic fibres. In the five brands of the analysed bottled drinking water, neither the packaging material polypropylene nor the bottle caps made of polyethylene were detected. These findings indicate that the analysed bottled drinking water was not contaminated by microplastic, but by micro debris of natural cellulose-based polymers.

Synthesis, characterization, and biodegradation studies of new cellulose-based polymers

New cellulose carbamates and cellulose acetate carbamates were prepared by classical addition reaction of isocyanates with alcohols. A Telomerization technique was used to make the grafted molecules strongly anchored and more hydrophobic. These molecules were grafted into cellulose and CA chains, respectively. The structures of the synthesized derivatives were confirmed using Nuclear Magnetic Resonance Spectroscopy, Fourier Transform Infrared and Thermogravimetric Analysis, and their solubility phenomenon was also established, and the carbamate derivatives showed better solubility compared to cellulose. Their ability to biodegrade was investigated, and it was concluded that Cell-P1 and CA-P1 derivatives are more biodegradable than the other samples. These results suggest that the resulting compounds can be used effectively in many useful industrial fields, for instance, eco-friendly food packaging, domains that use materials that are environmentally friendly and sustainable and the development of green chemistry.

Carboxymethyl Cellulose-Based Polymers as Promising Matrices for Ficin Immobilization.

The present work is devoted to research on the interaction between carboxymethyl cellulose sodium salt and its derivatives (graft copolymer of carboxymethyl cellulose sodium salt and N,N-dimethyl aminoethyl methacrylate) with cysteine protease (ficin). The interaction was studied by FTIR and by flexible molecular docking, which have shown the conjugates' formation with both matrices. The proteolytic activity assay performed with azocasein demonstrated that the specific activities of all immobilized ficin samples are higher in comparison with those of the native enzyme. This is due to the modulation of the conformation of ficin globule and of the enzyme active site by weak physical interactions involving catalytically valuable amino acids. The results obtained can extend the practical use of ficin in biomedicine and biotechnology.

Molecular interactions of niclosamide with hydroxyethyl cellulose in binary and ternary amorphous solid dispersions for synergistic enhancement of water solubility and oral pharmacokinetics in rats

The cellulose-based polymers are extensively employed in oral formulations for addressing ADMET issues of API. Herein, we report the synergistic effect of hydroxyethyl cellulose in solubility/dissolution enhancement of BCS class II, anthelmintic drug niclosamide. The low solubility and poor oral bioavailability are the primary reasons for its high daily dose. The amorphous solid dispersions (ASDs) developed herein demonstrated reproducible solubility and dissolution enhancement in smaller-to-pilot batches. The significant boost in niclosamide solubility in HEC-based binary SD was rationalized as a result of intermolecular H-bonding as indicated by in-silico studies and further supported by characterization data. HEC is plausibly inhibiting the precipitation of drug and thereby enabling high dissolution and permeation across the membrane. The comparative oral pharmacokinetics in Wistar rats at 25 mg/kg provided 4.4-fold higher plasma exposure of niclosamide in SD formulation SB-ASD-N2 over the plain drug. The results presented herein warrant validation of this ASD under clinical settings.

Applications of nanocellulose as biosensing platforms for the detection of functional biomacromolecules: A Review

Cellulose is a group of materials that can be made into low-cost devices because they are the most common biomaterials in nature. Cellulose-based polymers are flexible, biocompatible, biodegradable, and easy to functionalise and mass produce. Cellulosic substrates are attractive biosensing platforms because of their unique properties, exceptional simplicity, and compatibility with standard technologies. Furthermore, cellulose-based biosensing approaches can meet the following criteria for optimal diagnostic assays or devices: real-time connectivity; simplicity of specimen collection; affordability; specificity; sensitivity; user-friendliness; speed and robustness; and deliverability to end-users. As a result, cellulose is suitable for constructing novel analytical devices in the biosensing community. The use of cellulose as a nano-engineered matrix material has enabled recent advancements in biosensors. Several methodologies for producing cellulose-based composites for the fabrication of various biosensors have been described and reviewed. Biological macromolecules have immense importance in genetic and pathogenicity detection. Likewise, there are many research reports, but there is a gap regarding review in this area of biological macromolecule detection like nucleic acids and proteins. This study looked at this previously unexplored area as well as the unique features that make it a good choice for biosensing applications and the engineering features of cellulose-based biosensors. It also looked at how different analytical systems have used such matrices to detect biological macromolecules (DNA, proteins, and RNA) in different samples.

One-pot synthesis of PAMAM-grafted hyperbranched cellulose towards enhanced thermal stability and antibacterial activity

Cellulose is widely used as a biomaterial because of its good biodegradability and biocompatibility. In this study, the periodate oxidation method was used to prepare dialdehyde cellulose (DAC), which was then modified with polyamidoamine dendrimer (PAMAM G0) by the hyperbranched crosslinking synthesis to obtain novel dialdehyde cellulose-based polymers (DPs) with high thermal stability and antibacterial activity. The characterization found that PAMAM was successfully grafted onto the cellulose backbone. Moreover, the thermal weight-loss temperature of DPs decreased, the char yields increased, and the crystallinity decreased significantly as the amount of PAMAM increased. The crystallinity was about 46.50%. Specifically, when the ratio of the aldehyde group in DAC to the amine group in PAMAM was 1:1, the maximum thermal-denaturation temperature and weight-loss temperature (Tmax) of the DPs reached 136 ℃ and 365.8 ℃, respectively. In addition, DPs showed a uniform long-strip structure with a good particle size distribution, preventing the self-assembly and aggregation of cellulose and DAC. Disk diffusion tests showed that the DPs had significant antibacterial activity against Escherichia coli and Staphylococcus aureus, with the inhibition zone diameters reaching 13–15 mm. Thus, DPs with good thermal stability and antibacterial activity could be used as a new type of cellulose-based functional material.

Biodegradation of Polymers Used in Oil and Gas Operations: Towards Enzyme Biotechnology Development and Field Application.

Linear and crosslinked polymers are commonly used in the oil and gas industry. Guar-derived polymers have been extensively utilized in hydraulic fracturing processes, and recently polyacrylamide and cellulose-based polymers have also found utility. As these polymers are used during various phases of the hydraulic fracturing process, they can accumulate at formation fracture faces, resulting in undesired filter cakes that impede oil and gas recovery. Although acids and chemical oxidizers are often added in the fracturing fluids to degrade or ‘break’ polymer filter cakes, the constant use of these chemicals can be hazardous and can result in formation damage and corrosion of infrastructure. Alternately, the use of enzymes is an attractive and environmentally friendly technology that can be used to treat polymer accumulations. While guar-linkage-specific enzyme breakers isolated from bacteria have been shown to successfully cleave guar-based polymers and decrease their molecular weight and viscosity at reservoir conditions, new enzymes that target a broader range of polymers currently used in hydraulic fracturing operations still require research and development for effective application. This review article describes the current state-of-knowledge on the mechanisms and enzymes involved in biodegradation of guar gum, polyacrylamide (and hydrolyzed polyacrylamide), and carboxymethyl cellulose polymers. In addition, advantages and challenges in the development and application of enzyme breaker technologies are discussed.

Synthesis and characterization of cellulose-based graft copolymers crosslinked by gamma-irradiation for enhanced oil recovery applications

Cellulose-based polymers have garnered significant attention as potential candidates for use in enhanced oil recovery (EOR). The challenge in the design of EOR polymers is the need for materials with a high low critical solution temperature (LCST) and the ability to withstand harsh environmental conditions. In this study, cellulose-methylcellulose graft copolymers were prepared with different cellulose to methylcellulose weight ratios. The copolymerization was carried out using gamma radiation doses of 5, 15, and 25 kGy, respectively. The LCST of the copolymers were evaluated using differential scanning calorimetry analysis. The effect of salt addition on the LCST of the materials was studied using different phosphate-buffered saline (PBS) concentrations. The results showed that the cellulose monomer concentration increase from 0.1 to 0.5% in 2% methylcellulose dispersed in water reduced the LCST from 59 to 54°C. The hydrophobic nature of cellulose moieties induced the aggregation of the copolymers into core-shell micelles. Besides, higher gamma radiation doses lowered the LCST of the copolymers. The increase in the salt concentration in the PBS medium tended to decrease the LCST due to disrupted hydration structure of the polymer chains. This work revealed that cellulose-methylcellulose copolymers could be used in chemical EOR due to their high phase transition temperatures, preventing pore clogging and enhancing oil production in the producing wells.