Advanced nano-based manipulations of molasses in the cellulose and paper discipline: Introducing a master cheap environmentally safe retention aid and strength promoter in papermaking

This work introduces, for the first time worldwide, molasses – a byproduct of the sugar industry – as a master retention aid and strength promoter in papermaking. The paper nanocomposites produced in the present work – involving molasses, natural cellulose fibers, and kaolin – retained larger amounts of kaolin while exhibiting greater strength, as compared to their molasses-free counterparts. Recently, the authors have shown, for the first time, that the nanoadditive sucrose can overcome the ultimate fate of deterioration in strength of paper, due to addition of inorganic fillers such as kaolin. This deterioration was counteracted by incorporating the nanoporous structure of cellulose fibers with sucrose, which leads to incorporation beating of the fibers, and thus increases the strength of the produced paper nanocomposites. In addition, the nanoadditive sucrose was proven – for the first time – to act as retention aid for inorganic fillers such as kaolin. We called this phenomenon incorporation retention to differentiate it from the conventional types of retention of inorganic fillers. On the other hand, it is well established in the literature that using gums (including starch) as additives in papermaking enhances the strength of paper. Molasses contains both the nanoadditive (sucrose), and gums (including starch). Molasses is a byproduct of sugar industry, which is cheaper than sucrose; and a major part of sucrose lost in sugar industry resides in molasses. Moreover, molasses is an environmentally safe additive. Therefore, the nanoadditive (molasses) was chosen, in the present work, to be manipulated as a master strength promoting retention aid for inorganic fillers used in papermaking, such as kaolin.     

Performance of improved bacterial cellulose application in the production of functional paper

Aim: The purpose of this work was to study the feasibility of producing economic flame retardant bacterial cellulose (BC) and evaluating its behaviour in paper production. Methods and Results: This type of BC was prepared by Gluconacetobacter subsp. xylinus and substituting the glucose in the cultivation medium by glucose phosphate as a carbon source; as well as using corn steep liquor as a nitrogen source. The investigated processing technique did not dispose any toxic chemicals that pollute the surroundings or cause unacceptable effluents, making the process environmentally safe. The fire retardant behaviour of the investigated BC has been studied by non‐isothermal thermogravimetric analysis (TGA & DTGA). The activation energy of each degradation stage and the order of degradation were estimated using the Coats–Redfern equation and the least square method. Strength, optical properties, and thermogravimetric analysis of BC‐phosphate added paper sheets were also tested. Conclusions: The study confirmed that the use of glucose phosphate along with glucose was significant in the high yield production of phosphate containing bacterial cellulose (PCBC1); more so than the use of glucose phosphate alone (PCBC2). Incorporating 5% of the PCBC with wood pulp during paper sheet formation was found to significantly improve kaolin retention, strength, and fire resistance properties as compared to paper sheets produced from incorporating bacterial cellulose (BC). Significance and Impact of the Study: This modified BC is a valuable product for the preparation of specialized paper, in addition to its function as a fillers aid.     

Vaccination of biological cellulose fibers with glucose: a gateway to novel nanocomposites

This work introduces, for the first time worldwide, the means to preserve and protect the natural nanoporous structure of the never-dried plant cell wall, against the irreversible collapse, which occurs due to drying. Simultaneously, these means, used for the above-mentioned aim, provide a gateway to novel nanocomposite materials, which retain the super reactive and super absorbent properties of the never-dried biological cellulose fibers. The present work showed, for the first time worldwide, that glucose can be vaccinated into the cell wall micropores or nanostructure of the never-dried biological cellulose fibers, by simple new techniques, to create a reactive novel nanocomposite material possessing surprising super absorbent properties. Inoculation of the never dried biological cellulose fibers, with glucose, prevented the collapse of the cell wall nanostructure, which normally occurs due to drying. The nanocomposite, produced after drying of the glucose inoculated biological cellulose, retained the super absorbent properties of the never dried biological cellulose fibers. It was found that glucose under certain circumstances grafts to the never dried biological cellulose fibers to form a novel natural nanocomposite material. About 3-8% (w/w) glucose remained grafted in the novel nanocomposite.     

New nanocomposite materials reinforced with flax cellulose nanocrystals in waterborne polyurethane

New nanocomposite films were prepared from a suspension of cellulose nanocrystals as the filler and a polycaprolactone-based waterborne polyurethane (WPU) as the matrix. The cellulose nanocrystals, prepared by acid hydrolysis of flax fiber, consisted of slender rods with an average length of 327 +/- 108 nm and diameter of 21 +/- 7 nm, respectively. After the two aqueous suspensions were mixed homogeneously, the nanocomposite films were obtained by casting and evaporating. The morphology, thermal behavior, and mechanical properties of the films were investigated by means of attenuated total reflection Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and tensile testing. The results indicated that the cellulose nanocrystals could disperse in the WPU uniformly and resulted in an improvement of microphase separation between the soft and hard segments of the WPU matrix. The films showed a significant increase in Young's modulus and tensile strength from 0.51 to 344 MPa and 4.27 to 14.86 MPa, respectively, with increasing filler content from 0 to 30 wt %. Of note is that the Young's modulus increased exponentially with the filler up to a content of 10 wt %. The synergistic interaction between fillers and between the filler and WPU matrix played an important role in reinforcing the nanocomposites. The superior properties of the new nanocomposite materials could have great potential applications.     

Direct fabrication of all-cellulose nanocomposite from cellulose microfibers using ionic liquid-based nanowelding

All-cellulose nanocomposite was directly fabricated using nanowelding of cellulose microfibers as a starting material, in 1-butyl-3-methylimidazolium chloride (BMIMCl) as a solvent, for the first time. The average diameter of the reinforcing component (undissolved nanofibrils) in the nanocomposite made directly from cellulose microfibers (NC-microfiber) was 53 ± 16 nm. Owing to its high mechanical properties (tensile strength of 208 MPa and Young's modulus of 20 GPa), high transparency (76% at a wavelength of 800 nm), and complete barrier to air and biodegradability, the NC-microfiber is regarded as a high multiperformance material. The NC-microfiber made directly from cellulose microfibers showed similar macro-, micro-, and nanostructures and the same properties as those made from solvent-based welding of ground cellulose nanofibers (NC-nanofiber). Omitting the step of cellulose nanofiber production makes the direct production of all-cellulose nanocomposite from cellulose microfibers easier, shorter, and cheaper than using cellulose nanofibers as starting material. The direct nanowelding of macro/micrometer-sized materials is theorized to be a fundamental approach for making nanocomposites.     

Preparation and characterization of bionanocomposite fiber based on cellulose and nano-SiO2 using ionic liquid

Microcrystalline cellulose (MCC)/nano-SiO₂ composite fibers were processed from solutions in 1-allyl-3-methylimidazolium chloride (AMIMCl) by the method of dry-jet wet spinning. The oscillatory shear measurements demonstrated that the gel network formed above 10 wt% nano-SiO₂ and the complex viscosity increased with increasing nano-SiO₂. Remarkably, the shear viscosity of the nanofluids was even lower than solutions without nano-SiO₂ under high shear rates. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images revealed that well-dispersed particles exhibit strong interfacial interactions with cellulose matrix. Measurements on wide-angle X-ray diffraction (WAXD) indicated that the regenerated cellulose and nanocomposite fibers were the typical cellulose II crystalline form, which was different from the native cellulose with the polymorph of Type I. The tensile strength of the nanocomposite fibers was larger than that of pure cellulose fiber and showed a tendency to increase and then decrease with increasing nano-SiO₂. Furthermore, the nanocomposite fibers exhibited improved thermal stability.     

Green nanotechnology: a short cut to beneficiation of natural fibers

For the first time worldwide, it is shown that our novel nanocomposite produced from natural fibers vaccinated with glucose--by fully green nanotechnology--possesses surprising reactivity towards urea. Magic super absorbent carbamated nanocomposite cotton fabrics having remarkable distinguished properties were obtained in few minutes. It is well established that carbamates possess antibacterial effects. The produced magic nanocomposite fabrics, we discovered for the first time worldwide, find their use as woven or nonwoven hygienic pads, bandages or paper nanocomposites.     

A high strength nanocomposite based on microcrystalline cellulose and polyurethane

A high-strength elastomeric nanocomposite has successfully been prepared by dispersing microcrystalline cellulose in a polyurethane matrix. The resulting nanocomposites show increased strain-to-failure in addition to increased stiffness and strength compared to the unfilled polyurethane. The optimal composite contained 5 wt % cellulose. The average true strength for this composition was 257 MPa, compared with 39 MPa for the neat polyurethane, and showed the highest strain-to-failure. The improvements of stiffness, strength, as well as strain-to-failure are believed to be due to good interaction, by both covalent and hydrogen bonds, between the polyurethane and the cellulose nanofibrils.     

A novel nanocomposite film prepared from crosslinked cellulosic whiskers

Cellulose whiskers are increasingly being used as a reinforcing phase in polymer systems and their use is a growing area of importance in bionanocomposite research. Although the reinforcing effect of cellulose whiskers has been studied in various polymers, the impact of crosslinking cellulose whiskers has not been explored so far. This work deals with the development of novel cellulose nanocomposites, wherein the cellulose nanowhiskers are crosslinked with poly(methyl vinyl ether-co-maleic acid) and poly(ethylene glycol). The morphology of the nanocomposite was studied using atomic force microscopy (AFM), which revealed a network structure embedded in a continuous phase. The water sorption studies demonstrated that the crosslinked nanocomposites are capable of absorbing up to ～900% water and have potential to be used as hydrogels.     

Gum‐Like Nanocomposites as Conformable,Conductive, and Adhesive Electrode Matrix for Energy Storage Devices

The electrodes in energy storage devices, such as lithium/sodium ion batteries, are typical multicomponent system consisting of inorganic electrode particles, polymer binders, conductive fillers, current collectors, and other components. These components are usually porously combined by a polymeric binder to accomplish the required electrochemical functions. In spite of the great success, this classic porous configuration faces serious issues in mechanical stability and flexibility due to weak and instable structures/interfaces. Here, by learning from polymeric nanocomposites, a concept of electrode matrix is proposed based on a gum‐like nanocomposite, a dual‐conductive adhesive. As an electrode matrix, the gum‐like nanocomposite integrates the functions of binder, electrolyte, and conductive fillers. In particular, it shows strong adhesion, high electrical/ionic conductivities, and appropriate mechanical and self‐healing properties. Finally, it is demonstrated that, with the electrode matrix, battery electrodes can be fabricated into nonporous composite showing not only excellent mechanical flexibility/stability but also improved electrochemical performance when working with a gum‐like electrolyte.     

High performance edible nanocomposite films containing bacterial cellulose nanocrystals

Bacterial cellulose obtained from Gluconacetobacter xylinus in the form of long fibers were acid hydrolyzed under controlled conditions to obtain cellulose nanocrystals. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) confirmed the formation of rod like cellulose nanocrystals having an average diameter and length of 20 ± 5 nm and 290 ± 130 nm respectively. These nanocrystals were used to prepare gelatin nanocomposite films and characterized for elucidating its performance. The formation of percolated networks of cellulose nanocrystals within gelatin matrix resulted in improving the mechanical properties of nanocomposites. The moisture sorption and water vapor permeability (WVP) studies revealed that the addition of cellulose nanocrystals reduced the moisture affinity of gelatin, which is very favorable for edible packaging applications. Results of this study demonstrated the use of bacterial cellulose nanocrystals (BCNCs) in the fabrication of edible, biodegradable and high-performance nanocomposite films for food packaging applications at relatively low cost.     

Chemical force microscopy of cellulosic fibers

Atomic force microscopy with chemically modified cantilever tips (chemical force microscopy) was used to study the pull-off forces (adhesion forces) on cellulose model surfaces and bleached softwood kraft pulp fibers in aqueous media. It was found that for the –COOH terminated tips, the adhesion forces are dependent on pH, whereas for the –CH₃ and –OH terminated tips adhesion is not strongly affected by pH. Comparison between the cellulose model surfaces and cellulosic fibers under our experimental conditions reveal that surface roughness does not affect adhesion strongly. X-ray photoelectron spectroscopy (XPS) and Fourier Transformed Infrared (FTIR) spectroscopy reveal that both substrate surfaces have homogeneous chemical composition. The results show that chemical force microscopy can be used for the chemical characterization of cellulose surfaces at a nano-level.     

Tuning Nanofillers in In Situ Prepared Polyimide Nanocomposites for High‐Temperature Capacitive Energy Storage

Modern electronics and electrical systems demand efficient operation of dielectric polymer‐based capacitors at high electric fields and elevated temperatures. Here, polyimide (PI) dielectric composites prepared from in situ polymerization in the presence of inorganic nanofillers are reported. The systematic manipulation of the dielectric constant and bandgap of the inorganic fillers, including Al₂O₃, HfO₂, TiO₂, and boron nitride nanosheets, reveals the dominant role of the bandgap of the fillers in determining and improving the high‐temperature capacitive performance of the polymer composites, which is very different from the design principle of the dielectric polymer composites operating at ambient temperature. The Al₂O₃‐ and HfO₂‐based PI composites with concomitantly large bandgap and moderate dielectric constants exhibit substantial improvement in the breakdown strength, discharged energy density, and charge–discharge efficiency when compared to the state‐of‐the‐art dielectric polymers. The work provides a design paradigm for high‐performance dielectric polymer nanocomposites for electrical energy storage at elevated temperatures.     

Enhanced Energy Storage in Nanocomposite Capacitors through Aligned PZT Nanowires by Uniaxial Strain Assembly

The design of nanocomposite capacitors poses certain challenges due to the reduced dielectric strength resulting from the integration of typically high dielectric fillers into the polymer. In prior efforts it was demonstrated that increasing of the filler could lead to energy‐storage densities up to 19.3% above the neat polymer. To further enhance the energy density, a novel strategy is developed to align nanowires in a thermoplastic matrix by uniaxial stretching assembly. It is demonstrated that the energy‐storage capability of the nanocomposite can be enhanced through the alignment of lead zirconate titanate (PZT) nanowires (NWs) in the direction of the applied electric field compared to randomly oriented samples. The maximum energy density of the nanocomposites is as high as 1.28 J cm^?3 at a volume fraction of 40% PZT NWs (aspect ratio around 14) with axis of alignment in the direction of the electric field. The findings of this research could lead to broader interest due to development of the piezoceramic nanocomposites with enhanced dielectric properties for use in next‐generation energy‐storage and conversion devices.     

Green composites from sustainable cellulose nanofibrils: A review

Green composites are materials having ecofriendly attributes that are technically and economically feasible while minimizing the generation of pollution. In this context it refers to the combination of fully degradable fibers mostly cellulosic materials and natural resins to develop green composite materials. In the past decade, overdependence on petroleum products (synthetic polymers, resins, etc.) has consistently increased and on account of this, the researchers are now focusing more on green materials specially cellulosics. Cellulosic fibers in micro and nano scale are attractive to replace man-made fibers as reinforcement to make environmentally friendly green products. In this study, we will discuss the processing, extraction, properties, chronological events and applications of cellulose and cellulosic-based nanocomposite materials. Cellulosic nanocomposites are currently considered one of the most promising areas of scientific and technological development in the field of plant products. The aim of this review is to demonstrate the current state of development in the field of cellulose nanofibril based green composites research and application through examples.     

Use of FT-IR spectroscopy as a tool for the analysis of polysaccharide food additives

This work purposes the characterisation of food additive polysaccharides such as starch, glucomannan and carrageenan by the use of the information of the principal components of the FT-IR spectra in the 1200–800 cm⁻¹ wavenumber region. The application of a PCA to this spectral region showed that several features could be obtained: (a) Separation between Glc and Gal, both monomeric and polymeric, and identification of their characteristic wavenumbers. (b) Identification of the specific absorbance wavenumbers for sucrose, Fru, Ara, and Man. (c) Distinction of pectic polysaccharides from the remaining carbohydrate samples. (d) Separation within κ-, ι-, and λ-carrageenans. These results show that the FT-IR spectroscopy in the 1200–800 cm⁻¹ wavenumber region can be a very reliable technique for food authentication of polysaccharide-based additives and be used for a quick screening of polysaccharides used as additives in foodstuffs.     

New approach for utilization of cellulose derivatives metal complexes in preparation of durable and permanent colored papers

This work focused on studying the used of polymer complexes as a new approach for the preparation of high performance colored paper. In this respect, the paper strength, thermal stability, biological resistance, magnetic properties, as well as the durability of aged paper were evaluated. It was found that, using carboxymethyl cellulose–copper complexes [CMC–Cu(II)], as paper additive, enhances the strength properties of wood pulp paper sheet, and depends on the anion of the copper salt used and the pH-value during the preparation process. The best polymer complex is that produced from using copper sulfate as the origin of copper ion, at pH 5.4. Also, incorporating the CMC–Cu(II) complexes with wood pulp provides thermal stability, fire retardancy, biological resistance, magnetism, as well as durability to the paper sheets obtained.     

Synthesis and activity of NH2- and COOH-terminal elastase recognition sequences on cotton.

The application of peptide recognition sequences of elastase to fibers of wound dressings is a possible route to inhibiting high levels of destructive elastase in the chronic wound. For this reason we have synthesized the elastase recognition sequence Val-Pro-Val on both cotton cellulose, and carboxymethylated cellulose cotton (CMC) and prepared chromatography columns of these to examine elastase retention. The tripeptide was synthesized on cotton-based cellulose fibers both in sequence and as a tripeptide methyl ester. Glycine was employed as a linker of the recognition sequence to the cotton cellulose. Pre-treatment of cotton cellulose with cellulase improved the substitution level of glycine. The peptidocellulose conjugates were employed as a chromatographic stationary phase to assess elastase retention. The sequence Val-Pro-Val-OMe was amino-terminally anchored to carboxymethylated cotton and demonstrated retention of up to 58% of elastase when first applied to the column. Higher repetitive retention was demonstrated subsequently. Cotton gauze similarly modified with Val-Pro-Val-Gly cellulose was compared with untreated gauze for reduction of elastase activity in buffered saline. Solutions of elastase that were treated with Val-Pro-Val-Gly cellulose cotton gauze, demonstrated reduced elastase activity. This study demonstrates the use of elastase recognition sequences as sequestering agents of elastase when attached to cotton fibers and constitutes a model for the design of peptidocellulose analogs in dressing fibers for chronic wounds.     

Modification of cellulosic fibers by UV-irradiation. Part II: After treatments effects

This work presents the comparative study on the dyeing behavior of cellulose fibers in alkaline solutions and under the influence of UV radiation. The cellulosic fabrics were pretreated followed by conventional mercerization technique or treatment with UV irradiation. For different time duration the reorganization of cellulose fibers by swelling treatments in alkaline solutions results in numerous structural modifications, causing changes of their accessibility and/or reactivity. The results revealed that the swelling of the cellulosic fibers depends on type of pre-treatment, dose of the radiation and the concentration of alkaline solution used. SEM analysis confirmed that UV irradiation of the cellulosic fibers leads to a higher swelling in comparison with any concentration of NaOH treatment. In comparison of both the treatments, the mercerized cellulosic fibers have shown better tear and tensile strength as compared to the untreated and UV irradiated one. There is adverse effect of UV radiation on the mechanical properties of UV radiation. Moreover, no loss in weight was observed after exposing the cellulose fabrics surface to UV radiation.     

Stabilization of an intracellular Mucor circinelloides lipase for application in non-aqueous media

Different methods for stabilization of Mucor circinelloides lipase, facilitating its application in organic solvents were tested. Lipase was either isolated from the mycelium and immobilized on solid carriers (derivatives of cellulose, diatomaceous earth, modified porous glass) or immobilized in situ in the mycelium pellets and stabilized. The immobilized enzyme preparations were used for synthesis of sucrose, glucose, butyl and propyl oleates and caprylates, carried out in petroleum and di-n-pentyl ethers. Immobilized preparations of either crude or purified lipase isolated from the mycelium were at least 4–6 times less effective in sucrose esters synthesis than mycelium-bound lipase preparations. Lipase preparation with the highest synthetic activity was obtained by cross-linking of M. circinelloides mycelium pellets with glutardialdehyde (operational stability in sucrose caprylate synthesis was 94% after 4 runs (24 h each), and caprylic acid conversion was 91–85%). The best method for production of mechanically durable biocatalyst, which efficiently catalyzed sucrose esters synthesis, was found to be entrapment of the mycelium-bound lipase in polyvinyl pyrrolidone-containing chitosan beads solidified with hexametapolyphosphate.