Cellulose Macromolecules Research Articles

The Effect of Mechanochemical Treatment of the Cellulose on Characteristics of Nanocellulose Films.

The development of the nanomaterials with the advanced functional characteristics is a challenging task because of the growing demand in the market of the optoelectronic devices, biodegradable plastics, and materials for energy saving and energy storage. Nanocellulose is comprised of the nanosized cellulose particles, properties of which depend on characteristics of plant raw materials as well as methods of nanocellulose preparation. In this study, the effect of the mechanochemical treatment of bleached softwood sulfate pulp on the optical and mechanical properties of nanocellulose films was assessed. It was established that the method of the subsequent grinding, acid hydrolysis and ultrasound treatment of cellulose generated films with the significant transparency in the visible spectral range (up to 78 % at 600 nm), high Young’s modulus (up to 8.8 GPa), and tensile strength (up to 88 MPa) with increased ordering of the packing of the cellulose macromolecules. Morphological characterization was done using the dynamic light scattering (DLS) analyzer and transmission electron microscopy (TEM). The nanocellulose particles had an average diameter of 15–30 nm and a high aspect ratio in the range 120–150. The crystallinity was increased with successive treatments as shown by the X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis. The thermal degradation behavior of cellulose samples was explored by thermal gravimetric analysis (TGA).

The potential of TEMPO-oxidized nanofibrillar cellulose beads for cell delivery applications

The advanced development of cell carriers for regenerative medicine and cell therapy demands materials able to sustain cell viability prior to their delivery to the target tissue, an ability that can be controlled by the shape, size and degradability of the matrix. TEMPO-oxidized nanofibrillar cellulose (ToNFC) macromolecules are negatively charged and therefore can be easily formulated by ionotropic gelation into beads of varying sizes that can release their payload through an erosion-controlled process. We report here for the first time on the preparation of ToNFC beads via ionic gelation using CaCl2 and on their loading with OSTEO-1 rat bone cells, with a view to examine their capacity of sustaining the cell viability and of releasing the bone cells in a controlled manner. The initial results obtained demonstrate that ToNFC is able to protect the OSTEO-1 cells and to maintain their viability for at least 2 weeks. Following gradual disintegration of the beads, a significant cell release and subsequent proliferation was observed after 7 days. These results indicate the considerable potential of nanofibrillar cellulose (ToNFC) for applications in cell therapy and regenerative medicine.

Ultraviolet protection performance of cotton fabric modified by ionic liquid iron coordination complex

In order to endow cotton fabric with the full wave band (290–410 nm) ultraviolet (UV) protection property, ionic liquid iron coordination complex (ILICC) was applied to modify cotton fabric. ILICC was prepared by in situ reaction on the surface of the cotton fiber directly. The Fourier transform infrared spectra, thermogravimetric and differential scanning calorimetry curves indicated that the strong interaction between ILICC and cellulose macromolecules of cotton fiber occurred through the O-Fe bond. Scanning electron microscopy images and particle size analysis indicated that the surface of the modified cotton fiber was covered by the agminate ILICC particles with diameters of 700–1600 nm. Investigation on the UV protection performances indicated that the UV transmittances ( T%) of the modified cotton fabric were less than 1.3% for the full wave band (UVA and UVB) UV. The washing durability results showed that the UV protection factor values were more than 95 when the modified cotton fabric was washed with 30 st washing cycles. The reason for the excellent UV protection performance of the modified cotton fabric was absorption and shielding of ILICC particles to UV light.

Antisuperbug Cotton Fabric with Excellent Laundering Durability.

Multidrug-resistant superbugs are currently a severe threat to public health. Here, we report a novel kind of antisuperbug material prepared by irradiation induced graft polymerization of 1-butyl-3-vinyl imidazole chloride onto cotton fabric. The reduction of superbugs on this fabric is higher than 99.9%. Attributed to the strong covalent bonding between the graft chains and the cellulose macromolecules, the antisuperbug performance did not decrease even after 150 equiv of domestic laundering cycles. Covalent bonding also prevented the release of the antibacterial groups during application and guarantees the safety of the material, which was proved by animal skin irritation and acute oral toxicity tests.

Obtenção de substância surfactante a partir da modificação de celulose

A atenção mundial aos problemas ambientais tem motivado, nas últimas décadas, estudos sobre produção de substâncias oriundas da biomassa, por ser esta uma fonte renovável e seus derivados apresentarem baixo impacto ambiental. Dentre as substâncias extraídas da biomassa, a celulose tem tido destaque e emprego em diversas aplicações, pois a sua estrutura pode ser modificada originando produtos com diferentes propriedades de uso industriais. Este estudo teve por objetivo desenvolver uma rota tecnológica para a obtenção de substância surfactante de sisal (Agave sisalana) modificado com álcool láurico, a partir de xantato celulósico. O produto obtido foi caracterizado quimicamente por espectroscopia de absorção na região do infravermelho com transformada de Fourier (FT-ir) quanto à inserção do modificante na macromolécula celulósica e os resultados da referida análise mostram que o processo de modificação empregado foi efetivo. Análises de verificação da capacidade de dissolução e do grau de saponificação do novo produto, em meio aquoso, mostraram que o processo realizado conferiu boa dispersão e baixa grau de saponificação. O caráter anfifílico da celulose modificada, associado ao baixo grau de saponificação lhes conferiu atributos para uso em processos industriais.

Layer by layer assembly of nanosilver for high performance cotton fabrics

High performance cellulosic fabrics are of increasing attention as a wearable fabric with special functions. The current report deals with preparation of multifunctional cotton fabrics by using simple and facile layer by layer technique. Firstly, silver nitrate was reacted with carboxymethyl cellulose to prepare Ag nanoparticles-carboxymethyl cellulose composite. Multi-layers of the so-obtained composite were applied on the cotton fabrics using pad-dry-cure method. Ag nanoparticles were deposited with mean size of 18.2 nm onto cotton fabrics which served as a cross linker between carboxymethyl cellulose macromolecules and cotton macromolecular blocks. Application of composite multilayers brought new properties for the finished cloths such like coloration, ultraviolet resistance, electrical resistance and biocidal action. The ultraviolet transmission radiation was significantly reduced to 7-10 % after applying ten composite layers. Valuable antibacterial textiles which are required in different medical purposes could be successfully produced, as excellent antibacterial activities were achieved by using the reported method. The developed process can be easily adapted to the existing textile machinery, making it industrially viable to produce fabric’s versatility.

Sustainable Preparation of Copper Particles Decorated Carbon Microspheres and Studies on Their Bactericidal Activity and Catalytic Properties

Cu particles decorated carbon composite microspheres (CCMs) with a unique sesame ball structure have been prepared by combining the mass-producible spray drying technique with calcinations. The conventional cuprammonium cellulose complex solution obtained by dissolving cellulose in a cuprammonia solution has been applied as raw materials for the preparation of Cu(NH3)42+/cellulose complex microspheres via a spray drying process. The resulted Cu(NH3)42+/cellulose complex microspheres are then transformed into the Cu particles homogeneously decorated porous carbon spheres in situ by calcinations at 450 or 550 °C. The coordination effect between the Cu(NH3)42+ species and the hydroxyl groups of the cellulose macromolecules has been exploited for directing the dispersion of the Cu particles in the resultant composite CCMs. The antimicrobial effects of the CCMs are evaluated by determining the minimum growth inhibitory concentrations using Staphylococcus aureus and Escherichia coli as representatives, respecti...

Физика процесса получения древесины с прочностью стали

This review summarizes the processes followed in sequence by modifying the samples of natural wood in ultrasound, constituents compactioning and pulsed magnetic field. It is shown that the processing of samples by ultrasound allows plasticizing one of the major component of wood - lignin as effective as when it is exposed to highly toxic ammonia, previously used for this purpose. When plasticizing lignin is transferred from the glass in a plastic condition allowing to perform three-dimensional compaction of sample without its destruction. Then the most probable processes of absorption of ultrasound by wood samples are analyzed. Three-dimensional compaction of plasticized samples with their subsequent three-dimensional processing can significantly increase the hardness of the modified material. After compaction relaxation processes occur in samples. Therefore, analysis of the optimal parameters of thermal influence is made allowing speeding up the completion of these processes and stabilizing the new mechanical characteristics. Further impacts on such samples of relatively weak pulsed magnetic fields allow getting the material, not inferior in terms of mechanical properties to metallic specimens. Analysis of the processes occurring in such action in the wood samples suggests the hypothesis of the origin of additional covalent bonds such as C-O-C between macromolecules of cellulose. Further, the review discusses the possibility of such bonds. It has been shown that an important feature during exposure of sample to magnetic field is co-directivity of magnetic force lines and wood fibers. Exactly at such orientation of the samples in the field the maximum effect is achieved. Then the causes of this feature of magnetic influence are analyzed and the main conclusions are made; and assumptions about the possible use are made.

Carboxymethylcellulose (CMC) as a model compound of cellulose fibers and polyamideamine epichlorohydrin (PAE)–CMC interactions as a model of PAE–fibers interactions of PAE‐based wet strength papers

ABSTRACTCarboxymethylcellulose (CMC) is a cellulose derivative obtained by the carboxymethylation of some hydroxyl groups in the cellulose macromolecules. In this article, we use CMC as a model compound of cellulose fibers to study polyamineamide epichlorohydrin (PAE)–fibers interactions during the preparation of PAE‐based wet strength papers. The main advantages of the use of CMC to replace cellulose fibers are its water‐soluble character and the homogeneous reaction medium during mixing with PAE resin. Based on 13C cross‐polarization/magic angle spinning nuclear magnetic resonance (CP/MAS NMR) and Fourier transformed infra‐red (FTIR) spectroscopy, we prove the formation of ester bonds in PAE–CMC films boosted by a thermal posttreatment at 105°C for 24 h. These ester bonds are derived from a thermally induced reaction between carboxyl groups in the CMC structure and azetidinium ions (AZR) in the PAE resin. PAE‐based handsheets were prepared from 100% Eucalyptus fibers. After preparation, some samples were thermally posttreated (TP) at 130°C for 10 min and stored under controlled conditions (25°C and 50% relative humidity or RH). For lowest PAE dosage, storage of the not thermally posttreated (NTP) PAE‐based handsheets does not allow them to reach the tensile strength values of TP PAE‐based handsheets (at 130°C for 10 min), but the difference in terms of breaking length remains low. For the highest PAE addition level, NTP and TP PAE‐based handsheets exhibit close values of the breaking length from 30 days of storage under controlled conditions (25°C and 50% RH). When a thermal posttreatment is applied, the wet strength development of PAE‐based papers is a combined effect of homo‐ and co‐cross‐linking mechanisms. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42144.

Deterioration of contemporary and artificially aged cotton by selected fungal species

The scope of this study was an analysis of the deterioration of cotton fibres caused by selected strains of fungal species from historical cotton textile objects. Aged and non-aged cotton fabric specimens were inoculated with representative strains of the six highest frequency fungal species isolated from museum textile objects from different Slovene museums. The selected fungi were Aspergillus clavatus, Cladosporium cladosporoides, Fomes fomentarius, Hypoxylon fragiforme, Penicillium chrysogenum and Penicillium corylophilum. Their effects on contemporary and artificially aged cotton was examined by Raman spectroscopy, infrared spectroscopy, scanning electron microscopy, and tensile behaviour. These fungal species affected the cellulose structure and fabric properties differently. Among the fungi analysed, P. chrysogenum was least harmful to cotton-cellulose samples, while C. cladosporoides, F. fomentarius and H. fragiforme showed the greatest effects. The main structural changes were hydrolysis, depolymerisation, and decreased molecular order. Although not all of these fungal species are dangerous to cotton fibres, and hence to museum objects, they all cause visible changes that can lead to disintegration of these objects. Another important factor that accelerates the depolymerisation of cellulose macromolecules in cotton fibre is inappropriate storage conditions, which should be avoided at all costs, to preserve historical objects and artefacts.

Preparation and Performance of Phase Change Materials of PEGA-g-CEA

Polyethylene glycol acrylate-grfat-Cellulose-acrylate (PEGA-g-CEA) has been synthesized as side-chain-type solid-solid phase change materials for thermal energy storange through graft copolymerization. The composition and structure of the grafts and cellulose, phase transition properties and morphology of grafts were investigated by Fourier transform infrared spectrometer (FTIR), differential scaanning calorimentry (DSC) and optical microscopy. The results show that the polyethylene glycol (PEG) successfully grafted onto the cellulose macromolecule, and the solid-solid phase change materials with a certain phase transformation ability were obtained through this experiment.

Changes in the supramolecular structures of cellulose after hydrolysis studied by terahertz spectroscopy and other methods

Hydrogen bonding is one of dominant forces in crystalline cellulose and lignocellulose, however, it is still a big challenge to evaluate the changes in the hydrogen bonding strength. Here, we reported a new method for measuring the changes in the hydrogen bonding strength of cellulose-based materials by terahertz time domain spectroscopy (THz-TDS). Avicel, corncob and their residual substrates after enzymatic hydrolysis were chosen as the targeted cellulose to demonstrate this method. THz adsorption in the range 0.5–2.5 THz and refractive index in the range 0.5–1.0 THz provided a direct signal corresponding to an increase in the hydrogen bonding strength for the residual samples (Avicel and corncob) after enzymatic hydrolysis. The THz results were further compared with those obtained from X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis. As a quick and non-invasive technique, THz spectroscopy provides unique information about the changes in the hydrogen bonding strength of cellulose-based materials. Therefore, it is a promising way to directly evaluate the hydrogen bonding strength of cellulosic macromolecules.

Chemical cationization of cotton fabric for improved dye uptake

Cotton fabric is usually dyed with reactive dyes. During the dyeing process, a large amount of salt is required to achieve higher exhaustion of the dye from the dyebath onto the fiber. Dyeing of cotton with reactive dyes has a substantial environmental impact due to the discharge of a large volume of highly colored and saline effluents. Chemical cationization allows cotton fibers to be dyed without salt by chemically modifying cellulosic macromolecules to introduce positively charged sites. In this study, cotton fabric was cationized using (3-chloro-2-hydroxylpropyl) trimethyl-ammonium chloride (CHPTAC). Dye uptake was assessed using two reactive dyes, CI Reactive Blue 235 and CI Reactive Blue 19. Dye exhaustion kinetics were determined using a Datacolor-HueMetrix Monitor system. Analysis of variance demonstrated significant effects of CHPTAC concentration and exhaustion time on the percent exhaustion. Color strength at the end of the dyeing cycle was significantly higher for cationized fabrics compared to the control fabric. This work shows that treatment of cotton with CHPTAC enhanced dye uptake properties due to the introduction of cationic sites and resulted in superior dyeing without the addition of salt.

Host responses and metabolic profiles of wood components in Dutch elm hybrids with a contrasting tolerance to Dutch elm disease.

Changes occurring in the macromolecular traits of cell wall components in elm wood following attack by Ophiostoma novo-ulmi, the causative agent of Dutch elm disease (DED), are poorly understood. The purpose of this study was to compare host responses and the metabolic profiles of wood components for two Dutch elm (Ulmus) hybrids, 'Groeneveld' (a susceptible clone) and 'Dodoens' (a tolerant clone), that have contrasting survival strategies upon infection with the current prevalent strain of DED. Ten-year-old plants of the hybrid elms were inoculated with O. novo-ulmi ssp. americana × novo-ulmi. Measurements were made of the content of main cell wall components and extractives, lignin monomer composition, macromolecular traits of cellulose and neutral saccharide composition. Upon infection, medium molecular weight macromolecules of cellulose were degraded in both the susceptible and tolerant elm hybrids, resulting in the occurrence of secondary cell wall ruptures and cracks in the vessels, but rarely in the fibres. The (13)C nuclear magnetic resonance spectra revealed that loss of crystalline and non-crystalline cellulose regions occurred in parallel. The rate of cellulose degradation was influenced by the syringyl:guaiacyl ratio in lignin. Both hybrids commonly responded to the medium molecular weight cellulose degradation with the biosynthesis of high molecular weight macromolecules of cellulose, resulting in a significant increase in values for the degree of polymerization and polydispersity. Other responses of the hybrids included an increase in lignin content, a decrease in relative proportions of d-glucose, and an increase in proportions of d-xylose. Differential responses between the hybrids were found in the syringyl:guaiacyl ratio in lignin. In susceptible 'Groeneveld' plants, syringyl-rich lignin provided a far greater degree of protection from cellulose degradation than in 'Dodoens', but only guaiacyl-rich lignin in 'Dodoens' plants was involved in successful defence against the fungus. This finding was confirmed by the associations of vanillin and vanillic acid with the DED-tolerant 'Dodoens' plants in a multivariate analysis of wood traits.

Small angle X-ray study of cellulose macromolecules produced by tunicates and bacteria

The organisation of poly-glucan chains into cellulose macromolecular microfibrils has been studied using small angle X-ray scattering (SAXS). Three kinds of cellulose – bacterial cellulose (BC), nata-de-coco (NdC) (food grade bacterial cellulose) and tunicate cellulose (TC) have been investigated. Given the large ambiguity in literature on the microfibril dimensions owing to different methods and data analysis strategies, a method to extract dimensions of cellulose microfibrils using SAXS has been shown, which was found to be consistent across all the samples. The results have been verified with microscopy data. Two populations of microfibrils with different cross-section dimensions were identified. The dimensions of the rectangular cross-sections of BC were found to be 32nm by 16nm and 21nm by 10nm. The dimensions for NdC were calculated to be 25nm×8nm and 14nm×6nm and that for TC were determined to be 25nm×10nm and 15nm×8nm.

Effect of different synthesis conditions on the microstructure, crystallinity and solubility of Mg-substituted hydroxyapatite nanopowder

A series of the Mg-substituted nano-hydroxyapatite (Mg-n-HA) nanopowders were synthesized by chemical co-precipitation method under different conditions, including two reaction temperature of 70°C and 40°C, and two water-soluble macromolecules of carboxyl methyl cellulose and poly(acrylic acid). The influence of magnesium content, reaction temperature and macromolecules on the microstructure, crystallinity and solubility of Mg-n-HA were characterized using SEM, XRD, FTIR techniques and soaking in simulated body fluid (SBF) solution. The results showed that needle-like Mg-n-HA nanoparticle with Mg being successfully incorporated in HA lattice could be synthesized, and there was no obvious morphology difference among the Mg-n-HA nanoparticles synthesized under different conditions. However, the crystallite sizes, cell parameters and crystallinity evidently decreased with the increasing magnesium content, the lowering reaction temperature and the introducing of macromolecules. Moreover, the solubility in SBF soaking was greatly improved in comparison with n-HA due to their lower crystallinity.

Toward faster degradation for natural fiber reinforced poly(lactic acid) biocomposites by enhancing the hydrolysis-induced surface erosion

The poor and uncontrollable biodegradability of poly(lactic acid) (PLA)-based materials is one of the fundamental limitations for widening their applications. To regulate the degradation of PLA/ramie fiber biocomposites, the hydrophilicity of the composites was modified to attract more water attack by introducing water-soluble poly(ethylene glycol) (PEG). Analyses by characterization of sample size, weight loss and microstructure offered intensive information on the degradation behavior of PLA biocomposites. It was revealed that PEG indeed significantly enhanced the surface erosion process and thus facilitated the degradation rate. The biocomposite bar containing 15 wt% PEG completed degradation within 50 days, while only ~50 wt% mass lost for the control biocomposite sample without PEG. Morphological observation confirmed that PEG accelerated the penetration of outside water from the surface to the center driven by the diffusion-in process, which subsequently boosted the hydrolytic action of the PLA backbone ester groups. Our results indicated that the PEG induced water penetration governed the overall degradation kinetics. As a strong response to the degradation, the stiffness of the biocomposite bars suffered from drastic decrease while T g varied in a climbing trend within the early stage. Microscopic examination of degradation solution formed during hydrolytic degradation of the PLA biocomposites suggested oligomers or lactic acid monomers were released to the solutions. It was of great interest to observe PEG dissolved in the alkaline solution speeded the ramie fibers breaking down to tiny fragments and cellulose macromolecules which further regenerated into cellulose aggregates in various fantastic appearances like coral-like leaves and pine needles. Our success in regulating the degradation of PLA biocomposites also provides an instructive approach for other PLA based materials.

Innovative Technology for Multifunctionalization of Cotton Fabric through Cellulase Biotreatment, Reactive Dyeing and Easy Care Finishing

INNOVATIVE technology for preparation of multifunctionalized ….. cotton fabrics with high technical performance was established. The innovation entailed the following consecutive sequence: cotton fabrics were subjected to cellulase biotreatment followed by reactive dyeing then easy care finishing treatment. pH was adjusted at 7 before commencing dyeing and finishing. No washing or drying was involved in the sequence. The so obtained fabrics displayed high technical performance as monitored by color strength, wrinkle recovery angle, retained strength in addition to softness and smoothness. Anchoring the enzyme to the cotton fabric ought to be taken as one of the reasons accounting for such high performance. It is believed that the enzyme protein molecules are fixed and immobilized within the molecules structure of cotton via their attachment to the cellulose hydroxyls by the finish molecules. The latter acts as bridges connecting the protein molecules of the enzyme with the cellulose macromolecules of the cotton fabric.

Biosorption potentials of a novel green biosorbent Saccharum bengalense containing cellulose as carbohydrate polymer for removal of Ni (II) ions from aqueous solutions

In this research work, the potential of a novel green material obtained from Saccharum bengalense (SB) plant was investigated for the removal of Ni (II) ions from aqueous solution. Biomaterial SB composed of cellulose macromolecules and was used without any chemical treatment. Batch experiments were performed by considering the effect of contact time, SB concentration, pH of the solution and temperature. Results revealed that ∼87% of Ni was removed from aqueous solution at optimum conditions. Three typical kinetic models namely, pseudo first order, pseudo second order and Elovich equations were applied to interpret the kinetic data. To investigate the rate determining step, the intra-particle diffusion model was applied on the experimental data. The sorption process was well explained with pseudo second-order kinetic model. Adsorption isothermal data was examined by applying classical two parameters (Langmuir, Freundlich, Timken and Dubinin–Radushkevich) and three parameters (Redlich–Peterson, Toth and Sips models) and four parameters Fritz Schlunder Isotherm models. Based on R2 and χ2 the equilibrium sorption data was better fitted to Langmuir and Sips isotherm model than any other model. Thermodynamics parameters such as free energy change (ΔG°), enthalpy change (ΔH°) and entropy change (ΔS°) have been calculated respectively, which revealed the spontaneous, endothermic and feasible nature of adsorption process. The results of the present investigation suggest that S. bengalense can be used as an environmentally benign and low cost biomaterial for nickel removal from aqueous solution.

Effect of Urea/NaOH aqueous system on morphology and properties of cotton fabric

This paper was focused on comparing the effect of urea/NaOH aqueous system with that of single urea or NaOH treating system on cotton fabric morphology and properties. Optical microscopy (OM), scanning electron micrograph (SEM), Fourier transform infrared spectroscopy (FT-IR), and wide X-ray diffraction (WAXD) were used to study cotton fabric morphology and properties before and after treatment by urea/NaOH, single urea, and single NaOH treating systems. Results showed that the cotton fabric treated by urea/NaOH aqueous system had better dyeability than the samples untreated and treated by single urea or single NaOH treating systems. Obvious differences were observed in appearance and morphology of cotton fabrics before and after treatment by urea/NaOH aqueous system. The composition and the structure of urea/NaOH treated cotton fiber had no distinct changes, only except the reduced hydrogen bonding between cellulosic macromolecules. Tensile strength and elongation at break of cotton fabric showed a slight decrease after treatment by urea/NaOH system. In addition, shrinkage of area and weight reduction of urea/NaOH treated samples were higher than those of the samples untreated and treated by single urea or single NaOH treating system.