Cellulose Composite Materials Research Articles

Co-ground mineral/microfibrillated cellulose composite materials: Recycled fibers, engineered minerals, and new product forms

When pulp and minerals are co-processed in suspension, the mineral acts as a grinding aid, allowing cost-effective production of mineral/microfibrillated cellulose (MFC) composite materials. This processing uses robust milling equipment and is practiced at industrial scale. The resulting products can be used in many applications, including as wet- and dry-strength aids in paper and board production. Previously, we have reported that use of these MFC composite materials in fiber-based applications allow generally improved wet and dry mechanical properties with concomitant opportunities for cost savings, property improvements, or grade developments. Mineral/MFC composites made with recycled pulp feedstocks were shown to offer at least equivalent strength aid performance to composites made using virgin fibers. Selection of mineral and fiber allows preparation of mineral/MFC composites with a range of properties. For example, the viscosity of such formulations was shown to be controlled by the shape factor of the mineral chosen, effective barrier formulations were prepared, and mineral/MFC composites with graphite as the mineral were prepared. High-solids mineral/MFC composites were prepared at 75% total solids (37% fibril solids). When resuspended and used for papermaking, these high-solids products gave equivalent performance to never-dried controls.

In Situ and Ex Situ Designed Hydroxyapatite: Bacterial Cellulose Materials with Biomedical Applications.

Hydroxyapatite (HAp) and bacterial cellulose (BC) composite materials represent a promising approach for tissue engineering due to their excellent biocompatibility and bioactivity. This paper presents the synthesis and characterization of two types of materials based on HAp and BC, with antibacterial properties provided by silver nanoparticles (AgNPs). The composite materials were obtained following two routes: (1) HAp was obtained in situ directly in the BC matrix containing different amounts of AgNPs by the coprecipitation method, and (2) HAp was first obtained separately using the coprecipitation method, then combined with BC containing different amounts of AgNPs by ultrasound exposure. The obtained materials were characterized by means of XRD, SEM, and FT-IR, while their antimicrobial effect was evaluated against Gram-negative bacteria (Escherichia coli), Gram-positive bacteria (Staphylococcus aureus), and yeast (Candida albicans). The results demonstrated that the obtained composite materials were characterized by a homogenous porous structure and high water absorption capacity (more than 1000% w/w). These materials also possessed low degradation rates (<5% in simulated body fluid (SBF) at 37 °C) and considerable antimicrobial effect due to silver nanoparticles (10–70 nm) embedded in the polymer matrix. These properties could be finetuned by adjusting the content of AgNPs and the synthesis route. The samples prepared using the in situ route had a wider porosity range and better homogeneity.

Non‐Invasive, Non‐Enzymatic, Biodegradable and Flexible Sweat Glucose Sensor and Its Electrochemical Studies

AbstractGlucose oxidase‐free polymer composite sensing material, made of polyelectrolytic cellulose derivatives cross‐linked by an organic polycarboxylic acid and enhanced by a plasticizer, is reported. The polymer composite is a nontoxic material and is also biodegradable that degrades within 15 days in the soil. The material is extremely flexible and yet resilient in such a way to explicitly fit for application in wearable sensors. Electrochemical analysis of the material for glucose sensing properties with artificial sweat as the electrolyte revealed surprising results. The lowest detection limit observed in chronoamperometric analysis was 0.4 mM of glucose. Impedimetric analysis showed significant drop in impedance at 0.5 mM addition of glucose. The cellulose composite material gets reduced into H3O+ and H+ ions, on addition of glucose, which is confirmed through square wave analysis, chrono‐amperometry, impedance and cyclic voltammetry results. The changes in the functional group were also confirmed by FTIR analysis taken before and after the addition of glucose. Results obtained by electrochemical analysis were well correlated with the proposed reaction mechanism. The flexibility and strength of the cellulose composite film was analysed with nano‐indenter, it also showed an excellent folding endurance withstanding up to 86960 folds. The biocompatibility nature of the material was also tested with the help of 3T3 fibroblast cells.

Modification of the wood‐plastic composite for enhancement of formaldehyde clearance and the 3D printing application

AbstractAs the formaldehyde is one of the main indoor pollutants, the purpose of this study is to effectively remove indoor formaldehyde pollution by using environmentally friendly 3D printing ornaments. The wood 3D printing filaments cellulose/polylactic acid composite (Cellu/P) was selected as the starting material, and 3‐aminopropyltriethoxysilane (APTES) was used for chemical modification to obtain a series of cellulose composite materials with amino groups. The modified composite materials (APTES@Cellu/P) were characterized by Fourier transform infrared, X‐ray diffraction, scanning electron microscope, energy dispersive spectroscopy, thermogravimetric analysis, and mechanical tests, and a formaldehyde removal experiment was performed. The feasibility of 3D printing was evaluated, and the process of 3D printing‐functionalized customized ornaments was proposed, and then a school emblem was used for modeling, printing, and surface modification. Compared with the commercially traditional activated carbon, 3D printing‐customized ornaments of APTES@Cellu/P material has a better formaldehyde removal effect, and can even avoid the secondary pollution that is common to the activated carbon.

Biomimetic hydroxyapatite (HAP)/ Carboxymethyl Cellulose (CMC) composite materials for bone tissue engineering applications

Natural bone is a complex material with a well-designed architecture. To achieve successful bone integration and regeneration, the constituents and structure of bone-repairing scaffolds need to be flexible and biocompatible. Hydroxyapatite (HAp), the main constituent of bone minerals, has excellent biocompatibility, while carboxymethyl cellulose (CMC), comprised of a three-dimensional network, has high flexibility. Therefore, CMC/HAp composites have attracted attention for the advancement of bone tissue engineering. In this work, a carboxymethyl cellulose/hydroxyapatite (Ca10(PO4)6(OH)2; HAp) composite has been developed as a three dimensional scaffold for bone tissue engineering. Scanning electron microscopy revealed that the CMC/Hap composite had a sheet like structure. These results revealed that the amount of precipitated HAp in the CMC/HAp composites was affected by the amount of CMC used during preparation. Properties of composites can be improved at optimal filler content compared to the pure Hap in the perspective of various biomedical applications. We have characterized the surface morphology of the composite using SEM image and having with the observed well dispersion of Hap in the Cmc phase.

Mineral/microfibrillated cellulose composite materials: High performance products, applications, and product forms

When pulp and minerals are co-processed in aqueous suspension, the mineral acts as a grinding aid, facilitating the cost-effective production of fibrils. Furthermore, this processing allows the utilization of robust industrial milling equipment. There are 40000 dry metric tons of mineral/microfbrillated (MFC) cellulose composite production capacity in operation across three continents. These mineral/MFC products have been cleared by the FDA for use as a dry and wet strength agent in coated and uncoated food contact paper and paperboard applications. We have previously reported that use of these mineral/MFC composite materials in fiber-based applications allows generally improved wet and dry mechanical properties with concomitant opportunities for cost savings, property improvements, or grade developments and that the materials can be prepared using a range of fibers and minerals. Here, we: (1) report the development of new products that offer improved performance, (2) compare the performance of these new materials with that of a range of other nanocellulosic material types, (3) illustrate the performance of these new materials in reinforcement (paper and board) and viscosification applications, and (4) discuss product form requirements for different applications.

Superhydrophobic Cellulose Nanofiber-Assembled Aerogels for Highly Efficient Water-in-Oil Emulsions Separation

Here, we reported a facile strategy to create superhydrophobic aerogels via freeze-drying of silylated cellulose nanofibers and silica nanoparticles mixed suspensions. The as-prepared aerogels possessed a hierarchical porous structure with high roughness and low surface energy. The hierarchical rough structure and low surface energy endowed the resultant aerogels with superhydrophobicity (water contact angle up to 168.4°). Importantly, the composite aerogels could separate surfactant-stabilized water-in-oil emulsions without external pressure, with high separation efficiency (>99%) and high flux (1910 ± 60 L m–2 h–1). The aerogels were easily recyclable and showed great antifouling performance, which could meet the requirements for long-term use. We also assembled a simple device to collect oil directly from water-in-oil emulsions with the obtained aerogel and a self-priming pump. The fabrication of the composite aerogels in our work provides a versatile way to fabricate cellulose composite materials for ...

Hydrogen Bond Dynamics of Cellulose through Inelastic Neutron Scattering Spectroscopy.

This work explores the dynamics of hydrogen bond networks in cellulose through inelastic neutron scattering (INS) and periodic CASTEP calculations. Estimated spectra were based on the crystal structure of cellulose Iα and Iβ and replicate the INS spectrum of cellulose samples with remarkable similarity, allowing a reliable assignment of INS bands to vibrational modes of cellulose. Comparison of cellulose samples from varied sources, from bacterial to kraft pulp, allows the identification of characteristic INS bands, arising from C2-OH torsional motions, which easily identify which allomorph-Iα or Iβ-is prevalent. A high crystallinity index is revealed by the presence of well-defined INS bands associated with highly cooperative CH bending modes along the chain. Hydrating kraft cellulose samples clearly affects those INS bands related with the hydroxymethyl group, identified as the preferred binding site for water molecules. At high humidity content level, a significant proportion of the water molecules is aggregated in clusters within the amorphous cellulose domains. The formation of ice microcrystals leads to a partial disruption of the hydrogen-bond network, as can be concluded from the observed red-shift of the torsional OH vibrational modes. The full assignment and interpretation of cellulose's INS spectra herein provided is a sound basis for future use of INS spectroscopy in the characterization of functionalized cellulose fibers and composite materials.

Cellulose and chitin composite materials from an ionic liquid and a green co-solvent

We report on a method for the preparation of cellulose/chitin composite materials from the ionic liquid 1-butyl-3-methylimidazolium acetate and γ-valerolactone as a biosourced sustainable co-solvent. Element analysis and attentuated total reflectance Fourier transform infrared spectroscopy show that the average degree of acetylation of chitin in the composite materials was around 82.5%. This indicates that chitin is not deacetylated to chitosan during the dissolution process. The X-ray diffraction results show that the degree of crystallinity of the composite materials increases from amorphous to 59% with increasing chitin concentration accompanied by a developing crystallite size up to 3 nm. Mechanical testing yielded a maximum tensile stress of 4.7 MPa, an elastic modulus of 27.4 MPa and a breaking elongation of 78.7% for the composites with 80 wt% chitin. In addition, water contact angle measurements indicated that the presence of chitin rendered the materials more hydrophobic.

Structural Study of Cellulose-Iron Oxide Composite Materials

There are limited structural studies of iron oxide coated cellulose materials despite their use as adsorbents for the removal of waterborne arsenic species. This study reports on the structural characterization of cellulose-iron oxide composites at variable iron oxide content using spectroscopy methods (Raman, solids 13C NMR, powder X-ray diffraction (pXRD)) and thermal gravi-metric analysis (TGA). Iron oxide was supported onto cellulose (ca. 25 wt.%) without significant loss in the Fe coating efficiency, where the accessibility of the biopolymer -OH groups affect the coating efficiency and yield of the iron oxide-cellulose composite. Isotherm adsorption studies for cellulose, iron oxide species and the cellulose composite materials with roxarsone (3-nitro- 4-hydroxyphenylarsonic acid) were studied to characterize the surface chemical properties of these potential adsorbent materials.

Foam-formed cellulose composite materials with potential applications in sound insulation

Use of foam-formed cellulose composite materials is a viable alternative that provides potential savings in terms of raw materials, energy and water compared with conventional methods for obtaining the fibrous composites. This new innovative manufacturing method leads to obtaining porous materials with low density and low environmental impact, which could replace the petroleum-based products in different industrial application fields like sound control. In this paper is presented a methodology for producing low-density cellulose composite materials in foam media. In this methodology a surfactant is mixed with cellulose fibres (from virgin pulp and recovered papers) at high shear velocity (2000 r/min) to entrain air, dewatered on Buchner funnel under low vacuum and air dried in non-restrained conditions. The obtained composite materials have been tested by sound insulation parameters (sound transmission loss and absorption coefficients) using two experimental impedance tubes with four-microphone configuration and anechoic termination. Three samples of foam-formed cellulose composites and one water-formed composite sample were obtained. Their sound insulation performances were compared with two different commercially available petroleum-based materials currently used in sound insulation applications (i.e. expanded/extruded polystyrene). The experimental results show comparable performances between foam-formed cellulose composites and polystyrene-based samples, but in terms of the environmental impact, these materials can be an appropriate green alternative which can cut the costs of recycling process.

Gold nanoparticle and graphene oxide incorporated strontium crosslinked alginate/carboxymethyl cellulose composites for o-nitroaniline reduction and Suzuki-Miyaura cross-coupling reactions

Self-organized strontium ion crosslinked alginate/carboxymethyl cellulose composite materials with gold nanoparticles (Au-NPs) and graphene oxide (GO) were effectively fabricated using dissipative convective procedures followed by the freeze-drying method. Composite gels were characterized by using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy with Energy dispersive X-ray analysis (SEM-EDAX) and transmission electron microscopy (TEM) analysis. Moreover, thermal, mechanical and rheological properties were also performed to identify their strength and stability. The results revealed that Sr/Alg/CMC/Au and Sr/Alg/CMC/GO/Au composites showed remarkably porous structures with ordered capillaries; rheologically gel-like structures with high mechanical strength. Moreover, composites were tested for the reduction of o-nitroaniline and Suzuki-Miyaura cross-coupling reaction. The Sr/Alg/CMC/GO/Au composite competently reduced the o-nitroaniline within 2min (k=4.86×10−2s−1) with recyclability up to 7 consecutive cycles and also displayed 98% isolated yield (TOF value is 4900h−1) for Suzuki-Miyaura cross-coupling reaction with 6cycles recyclability. This approach of using nanoparticles incorporated composite systems as reusable catalysts opens a door of new materials for various catalytic applications.

Renewable Additives that Improve Water Resistance of Cellulose Composite Materials

Waste cardboard is an underutilized resource that can be redirected for the creation of safer and higher quality building materials for low-income housing in the developing world, as well as to produce better materials for in... | Find, read and cite all the research you need on Tech Science Press

Chiroptical, morphological and conducting properties of chiral nematic mesoporous cellulose/polypyrrole composite films

Conductive chiral nematic cellulose composite materials have been fabricatedvia in situoxidative chemical polymerization of pyrrole onto surface-modified mesoporous cellulose nanocrystal (CNC) films.

Synthesis of Ag-NPs impregnated cellulose composite material: its possible role in wound healing and photocatalysis.

Cellulose is the natural biopolymer normally used as supporting agent with enhanced applicability and properties. In present study, cellulose isolated from citrus waste is used for silver nanoparticles (Ag-NPs) impregnation by a simple and reproducible method. The Ag-NPs fabricated cellulose (Ag-Cel) was characterised by powder X-rays diffraction, Fortier transform infrared spectroscopy and scanning electron microscopy. The thermal stability was studied by thermo-gravimetric analysis. The antibacterial activity performed by disc diffusion assay reveals good zone of inhibition against Staphylococcus aureus and Escherichia coli by Ag-Cel as compared Ag-NPs. The discs also displayed more than 90% reduction of S. aureus culture in broth within 150 min. The Ag-Cel discs also demonstrated minor 2,2-diphenyl 1-picryl-hydrazyl radical scavenging activity and total reducing power ability while moderate total antioxidant potential was observed. Ag-Cel effectively degrades methylene-blue dye up to 63.16% under sunlight irradiation in limited exposure time of 60 min. The Ag-NPs impregnated cellulose can be effectively used in wound dressing to prevent bacterial attack and scavenger of free radicals at wound site, and also as filters for bioremediation and wastewater purification.

Cellulose, Chitosan and Keratin Composite Materials: Facile and Recyclable Synthesis, Conformation and Properties.

A method was developed in which cellulose (CEL) and/or chitosan (CS) were added to keratin (KER) to enable [CEL/CS+KER] composites formed to have better mechanical strength and wider utilization. Butylmethylimmidazolium chloride ([BMIm+Cl-]), an ionic liquid, was used as the sole solvent, and because the majority of [BMIm+Cl-] used (at least 88%) was recovered, the method is green and recyclable. FTIR, XRD, 13C CP-MAS NMR and SEM results confirm that KER, CS and CEL remain chemically intact and distributed homogeneously in the composites. We successfully demonstrate that the widely used method based on the deconvolution of the FTIR bands of amide bonds to determine secondary structure of proteins is relatively subjective as the conformation obtained is strongly dependent on the choice of parameters selected for curve fitting. A new method, based on the partial least squares regression analysis (PLSR) of the amide bands, was developed, and proven to be objective and can provide more accurate information. Results obtained with this method agree well with those by XRD, namely they indicate that although KER retains its second structure when incorporated into the [CEL+CS] composites, it has relatively lower α-helix, higher β-turn and random form compared to that of the KER in native wool. It seems that during dissolution by [BMIm+Cl-], the inter- and intramolecular forces in KER were broken thereby destroying its secondary structure. During regeneration, these interactions were reestablished to reform partially the secondary structure. However, in the presence of either CEL or CS, the chains seem to prefer the extended form thereby hindering reformation of the α-helix. Consequently, the KER in these matrices may adopt structures with lower content of α-helix and higher β-sheet. As anticipated, results of tensile strength and TGA confirm that adding CEL or CS into KER substantially increase the mechanical strength and thermal stability of the [CS/CEL+KER] composites.

Life Cycle Impacts of Natural Fiber Composites for Automotive Applications: Effects of Renewable Energy Content and Lightweighting

SummaryThis study examines the life cycle energy demand and greenhouse gas (GHG) emissions associated with substituting natural cellulose and kenaf in place of glass fibers in automotive components. Specifically, a 30 wt% glass‐fiber composite component weighing 3 kilograms (kg) was compared to a 30 wt% cellulose fiber composite component (2.65 kg) and 40 wt% kenaf fiber composite component (2.79 kg) for six cars, crossovers, and sport utility vehicles. The use‐phase fuel consumption of the baseline and substitute components, with and without powertrain resizing, were determined using a mass‐induced fuel consumption model based on U.S. Environmental Protection Agency test records. For all vehicles, compared to the baseline glass fiber component, using the cellulose composite material reduced life cycle energy demand by 9.2% with powertrain resizing (7.2% without) and reduced life cycle GHG emissions by 18.6% with powertrain resizing (16.3% without), whereas the kenaf composite component reduced energy demand by 6.0% with powertrain resizing (4.8% without) and GHG emissions by 10.7% with powertrain resizing (9.2% without). For both natural fiber components, the majority of the life cycle energy savings is realized in the use‐phase fuel consumption as a result of the reduced weight of the component.

Method of preparing stable composites of a Cu-aluminosilicate microporous compound and cellulose material and their characterisation

A new aluminosilicate cellulose composite material was prepared by coating hydrogel on a cotton fabric. An aluminosilicate material zeolite Faujasite (FAU) was synthesised for a series of desired properties, observing the possibilities of the isomorphous replacement of Al or/and Si atoms, within the structure, with copper. Aluminosilicate microporous material was prepared by convection hydrothermal synthesis, applying microwave energy. The selection and modification of the zeolite deposition procedures on the cellulose material was also carried out. The stability of the obtained cellulose material to washing was determined. The crystalline structure of the aluminosilicate samples and their composites with cellulose materials were checked employing X-ray diffraction analysis. The following analysis methods were used for physicochemical characterisation: Fourier transform infrared spectroscopy and field emission scanning electron microscope with EDS. Structural properties of the newly created composite materials were investigated using the following standard methods: surface mass according to ISO 3801:1977, determination of thickness according to ISO 5084:1996, tensile strength according to DIN EN ISO 13934-1 and air permeability according to HRN EN ISO 9237:2003. Completely new constructional properties, compared to the unprocessed cellulose material, of the newly formed composite materials are mainly evident from the following experimental results: the air permeability values decrease for both samples (59.87 and 61.76 % for Cel-AlSi 1_K and Cel-AlSi 1_M, respectively), the areal density change values (1.45 % for Cel-AlSi 1_K, 4.61 % for Cel-AlSi 1_M), the sample thickness increased by 21.55 % for both composite materials while the tensile strengths decrease slightly for both samples (5.83 % for Cel- AlSi 1_K, 6.41 % for Cel-AlSi 1_M).

Cellulose, chitosan, and keratin composite materials. Controlled drug release.

A method was developed in which cellulose (CEL) and/or chitosan (CS) were added to keratin (KER) to enable [CEL/CS+KER] composites to have better mechanical strength and wider utilization. Butylmethylimmidazolium chloride ([BMIm+Cl–]), an ionic liquid, was used as the sole solvent, and because the [BMIm+Cl–] used was recovered, the method is green and recyclable. Fourier transform infrared spectroscopy results confirm that KER, CS, and CEL remain chemically intact in the composites. Tensile strength results expectedly show that adding CEL or CS into KER substantially increases the mechanical strength of the composites. We found that CEL, CS, and KER can encapsulate drugs such as ciprofloxacin (CPX) and then release the drug either as a single or as two- or three-component composites. Interestingly, release rates of CPX by CEL and CS either as a single or as [CEL+CS] composite are faster and independent of concentration of CS and CEL. Conversely, the release rate by KER is much slower, and when incorporated into CEL, CS, or CEL+CS, it substantially slows the rate as well. Furthermore, the reducing rate was found to correlate with the concentration of KER in the composites. KER, a protein, is known to have secondary structure, whereas CEL and CS exist only in random form. This makes KER structurally denser than CEL and CS; hence, KER releases the drug slower than CEL and CS. The results clearly indicate that drug release can be controlled and adjusted at any rate by judiciously selecting the concentration of KER in the composites. Furthermore, the fact that the [CEL+CS+KER] composite has combined properties of its components, namely, superior mechanical strength (CEL), hemostasis and bactericide (CS), and controlled drug release (KER), indicates that this novel composite can be used in ways which hitherto were not possible, e.g., as a high-performance bandage to treat chronic and ulcerous wounds.

Development of a novel regenerated cellulose composite material.

We report for the first time on a new natural composite material achieved by blending cotton and duck feather using an ionic liquid. The addition of duck feather was found to improve the elasticity, strain at break, by 50% when compared to regenerated cellulose alone. This is a significant finding since regenerated cotton using ionic liquids often suffers from poor elasticity. The improved elasticity is likely due to the regenerated duck feather maintaining its helical structure. The new regenerated cellulose composites were characterized using a combination of dynamic mechanical analysis, Fourier transform infrared spectroscopy, thermal gravimetric analysis, contact angle measurements and scanning electron microscopy.