Water-soluble Biopolymer Research Articles

Water-soluble biopolymers calcium polymalate derived from fermentation broth of Aureobasidium pullulans markedly alleviates osteoporosis and fatigue

Osteoporosis is a prevalent condition characterized by bone loss and decreased skeletal strength, resulting in an elevated risk of fractures. Calcium plays a crucial role in preventing and managing osteoporosis. However, traditional calcium supplements have limited bioavailability, poor solubility, and adverse effects. In this study, we isolated a natural soluble biopolymer, calcium polymalate (PMACa), from the fermentation broth of the fungus Aureobasidium pullulans, to investigate its potential as an anti-osteoporosis therapeutic agent. Characterization revealed that linear PMA-Ca chains juxtaposed to form a porous, rod-like state, in the presence of Ca2+. In vivo mouse models demonstrated that PMA-Ca significantly promoted the conversion of serum calcium into bone calcium, and stimulated bone growth and osteogenesis. Additionally, PMA-Ca alleviated exercise fatigue in mice by facilitating the removal of essential metabolites, such as serum lactate (BLA) and blood urea nitrogen (BUN), from their bloodstream. In vitro studies further showed that PMA-Ca strengthened osteoblast cell activity, proliferation, and mineralization. And PMA-Ca upregulated the expression of some genes involved in osteoblast differentiation, indicating a potential correlation between bone formation and PMACa. These findings indicate that soluble PMA-Ca has the potential to be a novel biopolymer-based calcium supplement with sustainable production sourced from the fermentation industry.

Orally fast dissolving α-lipoic acid electrospun nanofibers mitigates lipopolysaccharide induced inflammation in RAW 264.7 macrophages

α-Lipoic acid (LA), a dietary supplement known for its strong antioxidant and anti-inflammatory potential, faces challenges due to its poor aqueous solubility and thermal instability. To address these issues, herein methyl-beta-cyclodextrin (M-β-CD) was utilized to create inclusion complex (IC) of LA in 1:1 M stoichiometric ratio of M-β-CD to LA. The LA-M-β-CD-IC was further combined with pullulan (PUL), a non-toxic and water-soluble biopolymer, for the development of electrospun nanofibers (NF) by green and sustainable approach. The resulting PUL/LA/M-β-CD NF formed as a self-standing and flexible material with an average diameter of 569 ± 129 nm and encapsulation efficiency of ∼86.90 %. The developed NF demonstrated an accelerated release, quick dissolution, and disintegration when exposed to artificial saliva replicating the conditions of oral cavity. PUL/LA/M-β-CD NF attenuated the production of ROS and NO by downregulating pro-inflammatory enzymes (iNOS and COX-2) in lipopolysaccharide (LPS) stimulated RAW 264.7 cells. Moreover, PUL/LA/M-β-CD NF also significantly downregulated the expression of pro-inflammatory cytokines including TNF-α, IL-6, and IL-1β along with suppression of NF-ĸB nuclear translocation in comparison to LA (at 250 μM). In nutshell, PUL/LA/M-β-CD NF demonstrated great potential as a rapid disintegrating delivery system for oral anti-inflammatory treatment due to the enhanced physicochemical characteristics of LA.

Hygrothermal ageing of dry gelatine adhesive films: Microstructure-property relationships

Gelatine adhesives, also known as animal glues, are collagen-based water-soluble biopolymers derived from vertebrate connective tissues. One of the various fields in which gelatine adhesives are widely used is the conservation of cultural heritage such as decorated furniture and panel paintings. It is observed that, with time, the failure in these objects often occurs along the adhesive bondlines. Given the moisture and temperature sensitivity of these adhesives, obtaining knowledge of their long-term behaviour, when exposed to climate variations, is pivotal. Here, the influence of hygrothermal ageing (exposure to a combination of elevated temperature and relative humidity (RH) cycling) on the microstructure and macroscopic properties of four different types of gelatine adhesives is investigated. These adhesives were selected from different animal origins namely bovine, rabbit, and fish with different Bloom strengths. It was observed that ageing cycles interfere with the most critical structural feature of protein chains namely triple helices. A clear decay in triple helix content at the micro-scale, determined by Differential Scanning Calorimetry (DSC) and X-Ray Diffraction (XRD) techniques, was observed which had implications on the macroscopic properties of these adhesives such as reduction of strain to failure and toughness (strain energy density to failure). The rate of decay in properties was revealed to be the highest in the adhesives with the lowest triple helix content. This study provides a scientific view of microstructure-property relationships in gelatinous adhesives as a function of environmental ageing, and stipulates the underlying mechanism of the degradation of mechanical properties as the loss of structural triple helices, regardless of the animal origin.

Pullulan-1-Ethyl-3-Methylimidazolium Tetrafluoroborate Composite as a Water-Soluble Active Component of a Vibration Sensor.

In recent years, the issue of electronic waste production has gained significant attention. To mitigate the environmental impact of e-waste, one approach under consideration involves the development of biodegradable electronic devices or devices that dissolve in the environment at the end of their life cycle. This study presents results related to the creation of a sensor that effectively addresses both criteria. The device was constructed using a composite material formed by impregnating a pullulan membrane (a biodegradable water-soluble biopolymer) with 1-Ethyl-3-Methylimidazolium tetrafluoroborate (a water-soluble ionic liquid) and coating the product with a conductive silver-based varnish. Capitalizing on the piezoionic effect, the device has demonstrated functionality as a vibration sensor with a sensitivity of approximately 5.5 × 10-5 V/mm and a resolution of about 1 mm. The novelty of this study lies in the unique combination of materials. Unlike the use of piezoelectric materials, this combination allows for the production of a device that does not require an external potential difference generator to function properly as a sensor. Furthermore, the combination of a biopolymer, such as pullulan, and an ionic liquid, both readily soluble in water, in creating an active electronic component represents an innovation in the field of vibration sensors.

Carboxymethyl cellulose-stabilized calcium phosphate particles for injectable hydrogel-based bone tissue engineering.

Calcium phosphate (CaP) is a widely used biocompatible and bioactive material for bone tissue engineering due to its similarity to the mineral component of natural bone. Amorphous calcium phosphate is a highly reactive form of CaP that can undergo a phase transformation into a more stable crystalline phase, making it an attractive candidate for bone regeneration applications. However, amorphous CaP is highly unstable in aqueous solutions, which limits its use in practical applications. To overcome this limitation, this research aimed to employ carboxymethyl cellulose (CMC), a water-soluble biopolymer, as a stabilizer for CaP particles. CMC can form a protective layer around CaP particles, enhancing their stability and dispersion in aqueous solutions. An in situ wet chemical process was used to prepare CaP/CMC particles. A concentration of 500 mg L-1 of CMC was found to effectively stabilize the synthesized CaP particles, resulting in good dispersity. These particles were then integrated into an injectable hydrogel made of methacrylated hyaluronic acid (MeHA) to create a promising material for bone regeneration applications. The use of CaP and CMC in combination with an injectable MeHA hydrogel provides a promising approach to develop a stable, injectable material for bone regeneration.

Preparation of chitosan derivative and its application in papermaking

To improve the paper strength, a number of resins and polymeric materials are being used, which is not environmental friendly and sustainable. Therefore, bio-based paper additives for the papermaking industry are essential. In this investigation, a water soluble biopolymer like carboxymethyl chitosan (CMCh) was prepared. The degree of substitution of the prepared CMCh was 2.49. The solubility of the prepared CMCh was 2.0 (w/v) % at 50 °C, and the conductivity increased with the increase of CMCh concentration in water. The prepared CMCh was applied as dry and wet strength agent of unrefined and refined softwood pulps. Both pulp increased dry and wet strength with increasing CMCh dose. An addition of 2.0 % CMCh increased dry strength by 125 % and wet strength by 293 % of unrefined pulp. On the other hand, the dry and wet tensile index of refined pulp increased from 59.48 N·m/g to 66.11 N·m/g and 2.48 N·m/g to 3.47 N·m/g, respectively, with the addition of 1.0 % CMCh. The CMCh was also used in filler modification. The precipitated calcium carbonate (PCC) modified with CMCh increased the ash content in paper with improved strength properties. The CMCh can be used in papermaking both for improving paper strength and filler retention.

Water-soluble biopolymers from heat-treated and high pressure homogenized vegetable purées: investigating their emulsion forming and stabilizing capacities.

The emulsion forming and stabilizing capacities of water-soluble biopolymers originating from the aqueous (serum) phase of heat-treated and high pressure homogenized purées were investigated. The serum biopolymers were characterized and then utilized as emulsifier/stabilizer in simple oil-in-water emulsions. The resulting emulsions were stored at 4°C and monitored for 2 weeks. Results revealed that carrot and tomato sera contained higher amounts of pectin and lower protein compared to broccoli. The serum pectic biopolymers exhibited distinct molecular structures, depending on the vegetable origin. Given these natural biopolymer composition and characteristics, emulsions with small droplet sizes were observed at pH 3.5. However, emulsions at pH 6.0 showed large mean droplet sizes, except for the emulsion formulated with carrot serum. Regardless of the pH, emulsions containing carrot serum biopolymers exhibited high capacity to form fine emulsions that were stable during the 2-week storage period at low temperature. This study clearly shows the capacity of natural water-soluble biopolymers isolated from the serum phase of vegetable purées to form fine emulsion droplets and maintain its stability during storage, especially in the case of carrot serum biopolymers.

Physicochemical characterization and cosmetic application of kelp blanching water polysaccharides

Seaweeds account for half of global mariculture and have become a key player in bio-based industries. Seaweed process typically starts with hot water blanching that helps reduce postharvest quality deterioration but also generates large amounts of hydrothermal waste. This study aims to explore the feasibility of isolating water-soluble biopolymers from seaweed hydrothermal waste and their potential applications. Using Saccharina japonica (formerly Laminaria japonica) blanching water as example, 2.9 g/L of polymeric substances were efficiently isolated by ultrafiltration, implying biopolymer coproduction potential of ~5.8 kt from blanching wastewater of current kelp industry. Physicochemical characterizations revealed polysaccharidic nature of the biopolymers, with high contents of fucose, uronic acids and sulfate, showing distinct but also overlapping structural features with hot water-extracted kelp polysaccharides. The main fraction of the blanching water polymers after anion exchange chromatography was acidic polysaccharide, the major backbone residues of which were (1–4) linked mannopyranose, (1–4) linked gulopyranose and (1–2) linked fucopyranose while the branched residues were primarily 1,3,4-, 1,2,4- and 1,4,6-linked hexoses but also 1,3,4-fucopyranose. Furthermore, the polysaccharides were found to have a good compatibility in cosmetic creams with added cohesiveness and freshness, demonstrating the application potential of such natural biopolymers from currently underexplored seaweed blanching water.

Detailed physicochemical study and thermodynamic aspects of the interaction between nonionic cellulose derivative hydroxyethyl cellulose and anionic surfactant sodium N-dodecanoyl sarcosinate in aqueous media

BackgroundThe scheme of this work was to study the interaction between hydroxyethyl cellulose (HEC), a non-ionic, water soluble biopolymer and sodium N-dodecanoyl sarcosinate (SDDS), a novel, environmentally friendly amino acid-based anionic surfactant in aqueous medium. The study of this type of interaction is relatively less complicated compared to that between a polymer and a surfactant with opposite charges. MethodsThe critical micelle concentration (CMC) of HEC-induced SDDS has been determined by various physicochemical methods such as tensiometry, conductometry, fluorimetry and microcalorimetry. Several thermodynamic and surface parameters related to the binding of SDDS with HEC have been assessed. The aggregation number (Nagg) of SDDS micelles in the presence of non-ionic HEC polymer has been measured by the steady-state fluorescence method. The hydrodynamic diameter (Dh) and zeta potential (ζ) of the polymer-surfactant aggregate have been measured by the dynamic light scattering method. The interaction study has further been amplified by detecting the change in the surface morphology of the polymer due to surfactant binding using Field Emission Scanning Electron Microscopy (FESEM) and high resolution transmission electron microscopy (HR-TEM) imaging in solvent-free state, as well as visualization of the HEC-SDDS micelle in the solution phase using fluorescence microscopy technique. Significant findingsFrom a physicochemical point of view, hydrophobic synergism seems to be important for understanding the interaction pattern of HEC-SDDS combination. In each scenario, the CMC of SDDS decreases with an increase in weight percentage of HEC. The aggregation number (Nagg) of SDDS micelles is also found to decrease with an increase in weight percentage of HEC in the medium. The hydrodynamic diameter (Dh) and zeta potential (ζ) of the polymer-surfactant aggregate, these two parameters have been found to be strongly dependent on the amphiphile concentration. Finally, investigations of the surface morphologies by taking Field Emission Scanning Electron Microscopy (FESEM), high resolution transmission electron microscopy (HR-TEM) and fluorescence microscopy techniques assist the experimental data.

Rapid preparation of Ru(0) nanoparticles stabilized with water-soluble biopolymer for hydrogen production from ammonia borane: Development of battery-like hydrolysis media

The biohybrid Na-Alg@Ru catalyst was prepared as a result of stabilizing Ru(0) nanoparticles with biopolymer chains of sodium alginate. The in-situ prepared Ru(0) nanoparticles had an average particle size of 1.023 ± 0.097 nm. The monodisperse Ru(0) nanoparticles prepared with a very practical, inexpensive and rapid method were used as a catalyst in hydrogen production by the hydrolysis reaction of ammonia borane (AB). The Na-Alg@Ru catalyst containing 3 mg Ru(0) metal catalyzed the hydrolysis of 50 mM AB with 100% yield, and the activation energy (Ea) of the reaction was estimated as 61.05 kJ mol−1. In addition, the Na-Alg@Ru nanoparticles were prepared with acrylamide as p(AAm)/Na-Alg@Ru hydrogel films suitable for use in hydrogen production in fuel cells, which represents a battery-like environment, and used for hydrogen production from AB. Thus, it was shown that the catalysts prepared in a few nm size could easily be used in battery-like environments.

Fast-Disintegrating Nanofibrous Web of Pullulan/Griseofulvin-Cyclodextrin Inclusion Complexes.

Griseofulvin (GSF) is one of the most widely used antifungal suffering from low water solubility and limited bioavailability. Here, cyclodextrin (CD) derivatives of hydroxypropyl-beta-CD (HPβCD) known for its high-water solubility were used to form inclusion complexes (ICs) with GSF. Here, the molecular modeling study revealed the more efficient complex formation with 1:2 (guest:CD) stoichiometry, so ICs of GSF-HPβCD were prepared using a 1:2 molar ratio (GSF:HPβCD) and then mixed with pullulan (PULL) to generate nanofibers (NFs) using the electrospinning technique. PULL is a nontoxic water-soluble biopolymer and the ultimate PULL/GSF-HPβCD-IC NF was obtained with a defect-free fiber morphology having 805 ± 180 nm average diameter. The self-standing and flexible PULL/GSF-HPβCD-IC NF was achieved to be produced with a loading efficiency of ∼98% corresponding to ∼6.4% (w/w) of drug content. In comparison, the control sample of PULL/GSF NF was formed with a lower loading efficiency value of ∼72% which equals to ∼4.7% (w/w) of GSF content. Additionally, PULL/GSF-HPβCD-IC NF provided an enhanced aqueous solubility for GSF compared to PULL/GSF NF so a faster release profile with ∼2.5 times higher released amount was obtained due to inclusion complexation between GSF and HPβCD within the nanofibrous web. On the other hand, both nanofibrous webs rapidly disintegrated (∼2 s) in the artificial saliva medium that mimics the oral cavity environment. Briefly, PULL/GSF-HPβCD-IC NF can be a promising dosage formulation as a fast-disintegrating delivery system for antifungal oral administration owing to the improved physicochemical properties of GSF.

SYNTHESIS AND THERMAL CHARACTERISTICS OF WATER-SOLUBLE BLOCKED O-TOLYLISOCYANATE

Synthesis of latent reagents, in particular isocyanates, in a water-soluble form is a promising direction of chemical research. The replacement of isocyanates with their blocked analogues allows solving several problems: increasing safety in the use and storage of such toxic compounds as isocyanates, facilitating multi-stage synthesis in active media, increasing the selectivity of the main reaction, reducing the toxicity of reagents. In addition, due to the possibility of carrying out the blocking reaction of isocyanates in an aqueous media, the environmental safety of the process of their production is increased and the yield of the product is improved. In order to synthesize a water-soluble latent monoisocyanate for the modification of polymer systems, including water-soluble biopolymers, water-soluble sodium 6-(o-tolylcarbamoylamino)hexanoate was synthesized by the interaction of ortho-tolyl isocyanate with an aqueous solution of sodium salt of 6-aminohexanoic acid. The optimal temperature conditions for the synthesis of water-soluble blocked ortho-tolyl isocyanate were determined. The structure of the reaction product was proved using methods of IR- spectroscopy with Fourier transform and NMR 1H spectroscopy. According to the data of thermogravimetric analysis in dynamic mode and pyrolytic mass spectrometry the temperature range of the thermal dissociation of water-soluble ortho-tolyl isocyanate blocked by the sodium salt of 6-aminohexanoic acid ranges from 100 to 140°C and is wider than the temperature range of the thermal dissociation of the hydrophobic compound - ortho- tolyl isocyanate blocked by ε- caprolactam.

De novo transcriptome assembly of Aureobasidium melanogenum CGMCC18996 to analyze the β-poly(L-malic acid) biosynthesis pathway under the CaCO3 addition

β-Poly(L-malic acid) (PMLA) is a water-soluble biopolymer used in food, medicine and other industries. To date, the biosynthesis pathway of PMLA has not been fully elucidated. In this study, we sequenced the transcriptome of strain Aureobasidium melanogenum under 20 g/L CaCO3 addition. The resulting sequencing reads were assembled and annotated for the differentially expressed genes (DEGs) analysis and novel transcripts identification. The result indicated that with the CaCO3 addition, the tricarboxylic cycle (TCA) cycle and glyoxylate pathway were up-regulated, and it also found that a non-ribosomal peptide synthetase (NRPS) like protein was highly expressed. The DEGs analysis showed a high expression level of malate dehydrogenase (MDHC) and phosphoenolpyruvate carboxykinase (PCKA) in the CaCO3 group, which indicated a cytosolic malate activity. We speculated that the malate should be transported to or synthesized in the cytoplasm, which was then polymerized to PMLA by the NRPS-like protein, accompanied by the up-regulated TCA cycle providing ATP for the polymerization. Depending on the analysis, we assumed that an NRPS-like protein, the TCA cycle, and the cytosolic malate together are contributing to the PMLA biosynthesis.

Properties and stability of water-in-water emulsions stabilized by microfibrillated bacterial cellulose

The stabilization of food-grade water in water (W/W) emulsions, as a potential candidate for encapsulating water-soluble functional components, remain a significant challenge in food science research. The main purpose of the work was to find a suitable particle for the preparation of the novel W/W emulsion. This system was composed of two immiscible water-soluble biopolymers (dextran and maltodextrin), and stabilized by using bacterial cellulose (BC) nanofibrils. The BC-stabilized W/W emulsions were successfully fabricated with the 20 wt% dextran (DEX) and the 10 wt% maltodextrin (MAL). There was no significant change in the droplet size of the emulsion with increasing BC surface charge from 0.41 mmol/g to 1.41 mmol/g dry cellulose. Meanwhile, the apparent viscosity, storage modulus ( G′ ) and loss modulus ( G″ ) of the emulsions were decreased with increasing BC surface charge. The stabilization mechanism of the W/W emulsion was due to the formation of viscoelastic network structure by BC nanofibrils. When the BC content increased from 0.04 wt% to 0.16 wt%, the emulsion droplet size was decreased from 3.78 ± 0.79 μm to 2.01 ± 0.40 μm. Furthermore, the obtained W/W emulsion did not demulsify within 7 d, it had better stability than that of the reported W/W emulsion. Moreover, the BC-stabilized emulsion was insensitive to the change of ionic strength concentration (0–200 mM) and pH (3–11). In brief, it was the first report to use BC nanofibrils to stabilize the W/W emulsion, which enriched the type of W/W emulsion. • A novel W/W emulsion was developed in dextran-maltodextrin aqueous mixture. • Bacterial cellulose nanofibers could be utilized to stabilize the W/W emulsion. • A dense network structure was formed by cellulose nanofibers in the DEX phase. • The stable W/W emulsion could be stored at room temperature for more than 7 d.

Gelatin and Alginate Binders for Simplified Battery Recycling

The water-soluble biopolymers, gelatin and sodium alginate, were investigated as potential alternative binders for use in lithium-ion battery anodes. The polymers were modified using a deep eutectic solvent (DES) made from choline chloride and glycerol. It was found that the addition of the DES resulted in greater plasticity and adhesion with respect to the unmodified binders and also to the current commonly used PVDF or CMC/SBR binders. Both the modified gelatin and sodium alginate binders are dispersible in water and can be rapidly delaminated by using mild ultrasound. These latter points are key steps in the function of the anode material and the subsequent recycling at the end of life. Imaging of the coatings formed using scanning electron microscopy and atomic force microscopy showed that the two types of binders dispersed themselves differently around the graphite particles, with the gelatin binder being distributed across the entire electrode surface, whereas the sodium alginate binder remained located at the hydrophilic edge planes of the graphite.

Pectin as a non-toxic crosslinker for durable and water-resistant biopolymer-based membranes with improved mechanical and functional properties

Biopolymer-based hydrophilic membranes with very high stability in aqueous systems were developed by using pectin as a non-toxic crosslinker. The unique properties of pectin as an efficient crosslinker were demonstrated using poly(vinyl alcohol) as a model for a highly water-soluble biopolymer. The chemical crosslinking strategy using glutaraldhehyde has proven successful in improving the stability of poly(vinyl alcohol) membranes. However, the use of non-toxic biological crosslinking agents has not been fully explored. We hypothesized that pectin, as a biopolymer bearing numerous carboxyl groups, could be a very efficient crosslinker compared to carboxylic acids, promoting unprecedented membrane stability. A systematic characterization of the chemical, thermal, mechanical, and functional properties of membranes prepared from poly(vinyl alcohol) crosslinked with pectin confirmed the excellent stability of the membranes in water, tested at the boiling point and at acidic and basic pH. The use of pectin also resulted in membranes with very high tensile strength, resistance to microbial degradation, antiradical and antibacterial activity, and improved water vapor barrier properties.

Rheology and Filtration Properties of Bentonite–Water Suspensions as Influenced by Lignocellulosic Nanomaterials and Water-Soluble Biopolymer Additives

Stability, structural morphology, and rheological and filtration properties of bentonite (BT)–water suspensions as influenced by the addition of lignocellulosic nanomaterials, including bleached nanofibrillated cellulose (NFC) and lignin-containing NFC (LNFC), and water-soluble polymers (WSPs) were investigated in this work. The performance of the formed fluids varied with the distinct fiber morphology and/or chemical composition of the NFC and LNFC. The NFC helped bridge BT particles for enhanced rheological performance but adversely affected filtration properties by forming thicker filter cakes. Reground NFC led to improved rheological properties owing to more individualized fibers with an enlarged surface area, but its effect on fluid loss was insignificant. LNFC enhanced viscosity, yield stress, and gelation properties of the fluid with effectiveness varying with the actual lignin content in the system. Enhanced filtration performance was seen with the presence of lignin in LNFC ascribed by its hydrophobic nature as well as the formation of more compact filter cakes. The applied biopolymers depicted better compatibility with smaller cellulosic fibril dimensions and lower lignin content. Thus, LNFC with moderate amounts of lignin in combination with biopolymer additives can help achieve much-improved rheological and filtration performance of BT-based fluids with lower cost and more environmental friendliness.

Experimental Investigation of a Mechanically Stable and Temperature/Salinity Tolerant Biopolymer toward Enhanced Oil Recovery Application in Harsh Condition Reservoirs

In search of robust polymers for enhanced oil recovery (EOR) application in reservoirs with harsh conditions, a water-soluble biopolymer was thoroughly investigated in this work to evaluate its applicability in such reservoirs. The experimental data revealed that compared to the commonly used EOR polymer, HPAM, the biopolymer was more efficient in thickening a brine solution as a result of its peculiar conformation. The presence of an electrolyte has almost no effect on the rheology of the biopolymer solution, even at an extremely high salt concentration (20 wt% NaCl). The relation between viscosity and the concentration curve was well fitted to the power-law model. Moreover, the rigid polymer chains rendered the polymer solution superior tolerance to elevated temperatures and salinity, but also led to considerable retention within tight porous media. The adsorption behavior was characterized by the average thickness of the hydrodynamic adsorbed layer on sand grains. The mechanical degradation was assessed by forcing the polymer solutions to flow through an abrupt geometry at ultra-high shear rates. The slight viscosity loss compared to HPAM proved the high mechanical stability of this polymer. These properties made it a promising alternative to HPAM in polymer flooding in the near future for high permeability oil reservoirs with harsh conditions.

Fabrication and properties of graphene oxide and reduced graphene oxide reinforced Poly(Vinyl alcohol) nanocomposite films for packaging applications

Petroleum-based polymers have a wide range of uses in the packaging industry, including films, food packaging, rigid containers, foamed containers, medical products, etc. This study focuses on improving the properties of polyvinyl alcohol (PVA) based material systems, one of the most popular water-soluble biopolymers, to reduce the waste of petroleum-based plastics, which are widely used. Polyvinyl alcohol (PVA) nanocomposite films containing low concentrations (0.05–1%) of graphene oxide (GO) and reduced graphene oxide (rGO) were produced via the solution casting method. When electrical properties of nanocomposite films were evaluated, the addition of 1 wt% GO and rGO resulted in a 36% and 45% decrease in the volumetric resistance of the films as well as a decrease in surface resistance of 24.5% and 34.9%, respectively. The maximum tensile strength of 1% GO and rGO-reinforced PVA nanocomposites was found to be ∼59 MPa and ∼68 MPa with an increase of 20% and 38% compared to neat PVA films, respectively. The average Young’s modulus of 1% GO and rGO-reinforced PVA nanocomposites also increased from 2561 MPa to 3515 MPa and 4219 MPa with an increase of 37% and 65%, respectively. As a result, the electrical conductivity, Young’s modulus, maximum tensile strength, thermal properties, and optical absorption of nanocomposite films increased by adding GO and rGO to PVA. The results show that the produced nanocomposite film may be a promising material for packaging applications.

Rheological Properties of Lignocellulosic Nanomaterial Aqueous Suspensions as Influenced by Water-Soluble Biopolymer Additives

Rheological properties including gel strength, steady-state viscosity, and oscillatory rheology of four types of cellulose nanomaterials (CNMs) under the influence of two different biopolymers were studied. The processed CNMs had distinct fiber morphology (individual fibril vs bundles with/without lignin particles), composition (lignin content varying from 52.88% to 6.86%), and surface chemical properties (zeta potential values from −28.62 mV to −13.4 mV). The presence of lignin in lignin-containing nanofibrillated cellulose (LNFC) decreased a suspension’s gel strength, viscosity, and dynamic modulus. The chosen bleached NFC contained large fibril bundles, and the processed material with more individualized fibril and enhanced fluid rheology was demonstrated after regrinding the original NFC. Biopolymer xanthan gum (XG) showed a much larger effect in modifying gel strength, viscosity, and dynamic moduli compared with polyanionic cellulose (PAC). Among the three chosen rheological models, the Nasiri–Ashrafizadeh model fitted the measured shear stress and shear rate data the best for each fluid system with correlation coefficients larger than 0.99. The use of biopolymers (e.g., XG and PAC) helped reduce negative effect of lignin on gel strength and other rheological properties for LNFC. The much-improved rheological performance for biopolymer-modified LNFC suspensions open new opportunities for CNMs to be used as more environmentally friendly fluids for the energy industry.