Microfibrillated Cellulose Research Articles

Micro-fibrillated cellulose reinforced eco-friendly polymeric resin from non-edible ‘Jatropha curcas’ seed waste after biodiesel production

Eco-friendly polymeric resin with desirable mechanical and physical properties was developed from non-edible protein extracted from Jatropha curcas (Jatropha) seed cake, so far considered as an agro-waste after oil extraction for bio-diesel conversion.

Effect of stretching on the mechanical properties in melt-spun poly(butylene succinate)/microfibrillated cellulose (MFC) nanocomposites

In order to prepare poly(butylene succinate)/microfibrillated cellulose composites with high performance, in this work, microfibrillated cellulose (MFC) was first treated by acetylchloride with ball-milling to improve its interfacial compatibility with poly(butylene succinate) (PBS). Then melt stretching processing was adopted to further improve the dispersion and orientation of MFC in as-spun PBS fiber. And the effect of MFC on the crystalline structure and mechanical properties were systematically investigated for the melt-spun fibers prepared with two different draw ratios. The dispersion, alignment of the MFC and interfacial crystalline structure in the composite fibers are significantly influenced by the stretching force during the melt spinning. The possible formation of nanohybrid shish kebab (NHSK) superstructure where aligned MFC as shish and PBS lamellae as kebab has been suggested via SEM and SAXS in the composite fibers prepared at the high draw ratio. Large improvement in tensile strength has been realized at the high draw ratio due to the enhanced orientation and dispersion of MFC as well as the formation of NHSK.

Investigation of the mechanism and effectiveness of cationic polymer as a compatibilizer in microfibrillated cellulose-reinforced polyolefins

The reinforcement effect of microfibrillated cellulose (MFC) in high-density polyethylene (HDPE) was investigated by mechanical, thermal, and rheological analysis. The reinforcement effect using both maleic-anhydride-grafted polypropylene (MAPP) and cationic polymer using primary amine (CPPA) as coupling agents in MFC-reinforced polypropylene (PP) has been reported in our previous study (Suzuki et al. in Cellulose 21:507–518, 2014. doi: 10.1007/s10570-013-0143-9 ). The combined use of MAPP and CPPA showed a greater reinforcement effect in the MFC-reinforced HDPE composite than in MFC-reinforced PP. The tensile modulus of MFC-reinforced HDPE was about 22 % higher than that of MFC-reinforced PP. Rheological analysis showed that there was a drastic improvement in the interaction between MFC and HDPE using CPPA and MAPP. The storage modulus of the MFC/HDPE composite in the melt state using MAPP and CPPA as coupling reagents was about three times higher than that without the coupling reagents. Furthermore, differential scanning calorimetry analysis suggested that a chemical reaction occurred between MAPP and CPPA. In addition, the thermal properties of MFC-reinforced HDPE were remarkably improved using MAPP and CPPA: the coefficient of thermal expansion of the composite decreased from 237.2 (HDPE) to 57.1 ppm/K (MFC/HDPE/MAPP/CPPA) and the heat distortion temperature under 0.45 MPa load improved from 67.4 (HDPE) to 116.7 °C (MFC/HDPE/MAPP/CPPA).

All-cellulose composites based on microfibrillated cellulose and filter paper via a NaOH-urea solvent system

All-cellulose composites were produced by partial dissolution of two cellulosic sources in a mixture of sodium hydroxide and urea at low temperature. Filter paper (FP) and microfibrillated cellulose (MFC) were used to examine the role of the fiber dimensions of the initial reinforcing network on the final mechanical properties of thin self-reinforced all-cellulose composites. The dissolution time was used to control the extent of the transformation. The initial fiber structure was progressively transformed into a thoroughly consolidated composite material. X-ray diffraction and Fourier-transform infrared spectroscopy were able to show that the initial cellulose I allomorph was replaced with a cellulose II allomorph. FP underwent a fast crystallinity loss and transformation to cellulose II. In contrast, the crystallinity of MFC decreased slowly after dissolution. This result was also correlated with a slower allomorphic transformation. The crystallinity of MFC decreased to a level comparable to that of FP after 40 min and it remained comparatively unaffected at extended dissolution times. Comparison between powder and transmission XRD measurements demonstrated that the cellulose II present in all films after dissolution was strongly textured with its (1 $$\bar{1}$$ 0) plane lying parallel to the sample surface despite fibrous microstructural features remaining from the initial substrates. The tensile strength and elastic modulus of FP increased significantly (+690 and +528 %, respectively) after only 20 min, while that of MFC remained relatively unaltered as a function of the dissolution time.

Reliable dn/dc Values of Cellulose, Chitin, and Cellulose Triacetate Dissolved in LiCl/N,N-Dimethylacetamide for Molecular Mass Analysis.

Freeze-dried microfibrillated cellulose (MFC) was directly dissolved in 8.0% w/w lithium chloride/N,N-dimethylacetamide (LiCl/DMAc), and MFC/LiCl/DMAc solutions with accurate MFC concentrations were prepared. The different MFC solutions were diluted to 1.0% and 0.5% w/v LiCl/DMAc, and subjected to size-exclusion chromatography with multiangle laser-light scattering and refractive index analyses (SEC/MALLS/RI), and off-line RI analysis to determine their refractive index increments (dn/dc). Chitin, cellulose triacetate, a poly(styrene) standard, and cellobiose were used for comparison. Each of the two determination methods gave different dn/dc values for MFC and chitin but similar dn/dc values for cellulose triacetate and poly(styrene). The anomalously small dn/dc values of MFC and chitin were explainable in terms of stable cellulose-LiCl and chitin-LiCl structures (i.e., formation of apparent covalent bonds between hydroxyl groups and LiCl) in the solutions. Thus, the SEC/MALLS/RI method provides reliable molecular mass parameters for cellulose and chitin.

Micro-Fibrillated Cellulose Preparation with Enzyme Beating Pretreatment and Effect on Paper Strength Improvement

Micro-Fibrillated Cellulose Preparation with Enzyme Beating Pretreatment and Effect on Paper Strength Improvement

Facile Template Synthesis of Microfibrillated Cellulose/Polypyrrole/Silver Nanoparticles Hybrid Aerogels with Electrical Conductive and Pressure Responsive Properties

Sustainable microfibrillated cellulose (MFC) aerogels are considered to be good templates for the growth of functional organic or inorganic nanoparticles. In this work, MFC aerogels with high porosity (99.9%) and low density (2.91 mg/cm3) were produced by freeze-drying. Then the obtained MFC aerogels were used as templates for the synthesis of MFC/polypyrrole (PPy)/silver nanoparticles (Ag) hybrid aerogels by a simple dip-coating method. Our results demonstrated that the obtained hybrid aerogels maintained the attractive features of the pristine MFC aerogels, such as high porosity, low density, and high compressive stress, during the preparation process. Compared with MFC aerogels and MFC/PPy hybrid aerogels, the MFC/PPy/Ag hybrid aerogels exhibited enhanced antimicrobial and electrical conductive properties due to the combination of PPy and Ag. Moreover, the electrical conductivity and compressible properties of the MFC/PPy/Ag hybrid aerogels led to their pressure responsive property. These features make...

Effect of addition of microfibrillated cellulose to urea-formaldehyde on selected adhesive characteristics and distribution in particle board

Several studies demonstrate that the addition of microfibrillated cellulose (MFC) to urea-formaldehyde (UF) wood adhesive improves the mechanical bond strength of wood particle board. In order to elucidate potential underlying mechanisms, the distribution of unmodified UF as well as MFC-modified UF (UF-MFC) in particle board was studied by means of light microscopy. The viscosity and cure characteristic of the adhesive systems were also characterised. UF-MFC showed high viscosity and shear thinning compared to UF. Both chemical and mechanical cure of adhesive were delayed in the presence of MFC. In UF-MFC, the size distribution of adhesive particles shifts towards larger particles compared to UF. More adhesive is directly available for adhesive bonding, and a larger part of the wood is covered with adhesive. This may be the cause for the better mechanical performance of particle board bonded with UF-MFC compared to UF.

Processing of wood-based microfibrillated cellulose and nanofibrillated cellulose, and applications relating to papermaking: a review

As an emerging cellulosic nanomaterial, microfibrillated cellulose (MFC) and nanofibrillated cellulose (NFC) have shown enormous potential in the forest products industry. The forest products industry and academia are working together to realise the possibilities of commercializing MFC and NFC. However, there are still needs to improve the processing, characterisation and material properties of nanocellulose in order to realise its full potential. The annual number of research publications and patents on nanocellulose with respect to manufacturing, properties and applications is now up in the thousands, so it is of the utmost importance to review articles that endeavour to research on this explosive topic of cellulose nanomaterials. This review examines the past and current situation of wood-based MFC and NFC in relation to its processing and applications relating to papermaking.

Natural active molecule chemical grafting on the surface of microfibrillated cellulose for fabrication of contact active antimicrobial surfaces

In this work, a naturally occurring phenyl isothiocyanate (PITC) molecule was covalently bonded to the surface of microfibrillated cellulose (MFC) to prepare contact active antimicrobial surfaces based on presently used materials. A preliminary comparative study was carried out on the reactivity of the hydroxyl group of cellulose and lignin compounds with phenyl isothiocyanate. Classical second order reaction kinetics was established between the hydroxyl containing model alcohol compounds and phenyl isothiocyanate with the conversion up to 80% in 20min. X-ray diffraction and scanning electron microscopy (SEM) were utilized to monitor the change in crystallinity and morphology of the surface after grafting. Further, the successful immobilization of isothiocyanate was confirmed after grafting with contact angle measurements, Fourier transform infrared spectroscopy (FTIR) and presence of sulfur by elemental analysis. Antibacterial activity was investigated against gram positive bacteria, Staphylococcus aureus and Bacillus subtilis, in dynamic and static experimental conditions. The PITC grafted MFC did not exhibit a bactericidal activity in dynamic condition, however, a very strong activity (complete killing) was revealed under static condition with 3.5 log initial CFU. These findings may help in the establishment of new and safe strategy for the preparation of antimicrobial contact surfaces for packaging applications.

The effect of freezing speed and hydrogel concentration on the microstructure and compressive performance of bamboo-based cellulose aerogel

Cellulose aerogel is a kind of ultra-light solid material which resulting from natural cellulose materials, and its performance is highly related to its structure. In this study, we prepared cellulose aerogels with different densities by regulating the concentration of microfibrillated cellulose (MFC) hydrogel using bamboo parenchymal cells as a starting material. The effects of the freezing speed and hydrogel concentration on the microstructure and compression performance of the resultant aerogels were investigated. The results demonstrated that higher freezing speed can inhibit the aggregation of MFC, resulting in aerogel with higher porosity. Conversely, increasing hydrogel concentration facilitated the aggregation of MFC, generating a distinct conversion from a looser fibril network structure (low density) to a more compact sheet-like structure (high density). Moreover, the results showed an expected positive correlation between the density of the aerogel and its compression performance, both in compression modulus and energy absorption.

Use of Microfibrillated Cellulose/Lignosulfonate Blends as Carbon Precursors: Impact of Hydrogel Rheology on 3D Printing

The aim of the present study was to investigate the rheological properties of microfibrillated cellulose (MFC)/lignosulfonate (LS) hydrogels and to use them in the manufacture of carbon objects by 3D printing and carbonization. For this purpose, both flow mode and thixotropic mode were used to characterize the hydrogel rheological behavior, which was subsequently used to search for formulation/processability correlations during 3D printing of square cuboids. At a concentration of 2%, MFC displayed excellent printability, i.e., shear-thinning behavior with high yield stress and a viscoelastic response to a step-down shear rate variation. The addition of LS induced a drop in the yield stress, and above an LS mass fraction of 30%, the MFC/LS hydrogels displayed an inelastic thixotropic response with a drop in printability (viz., the printed cuboids underwent a continuous deformation until spreading of the hydrogel was complete). Above 50% LS, the high viscosity slowed the flow of the MFC/LS hydrogels, and th...

Nanocellulose Films from Amazon Forest Wood Wastes: Structural and Thermal Properties

The aim of this work was to determine the best fibrillation intensity that should be used to produce high crystalline and thermal stable microfibrillated cellulose (MFC) and nanocellulose films fromC. goeldianaveneer wastes. The number of passages (cycles) of cellulose suspension tested in grinder were 10, 20, 30 and 40. Important properties to be analyzed included changes in morphology from the raw wood to the nanocellulose films, increases/decreases in cellulose crystalline index for inference on biomaterial strength, and thermal behavior changes to support conclusions on biomaterials processing and application possibilities. After chemical treatments for cellulose isolation, mechanical shearing was applied to produce cellulose nanostructures; hence nanocellulose films could be successfully produced fromC. goeldianawood wastes. Influence of more refining cycles on thermal properties, indicated higher stability for 40-cycles nanocellulose films. In general, grinder refining process decreased crystalline index of cellulose.

An Efficient Dispersive Agent — KCl for Ultrasonic Preparation of Microfibrillated Cellulose (MFC)

The suitability of saturated salt solutions as a dispersive agent for preparing microfibrillated cellulose (MFC) from bamboo processing residue through ultrasonication was evaluated. The effect of pure water and KCl solution on the rheological behavior and morphologies of prepared MFC were compared. The results show that the viscosity of MFC suspension dispersed in KCl solution decreases by several orders of magnitude compared to the water counterpart. SEM images demonstrate that MFCs with comparable quality can be prepared using either pure water or KCl solution as a dispersive agent. A high concentration of bamboo processing residue (~2 wt.%) dispersed in salt solutions was found to possess comparable viscosity with a low concentration of MFC suspension (~0.5 wt.%) dispersed in water. This indicates that the application of salt solutions as dispersive agents in ultrasonication has great potential to improve the productivity of MFC prepared from plant materials.

Contact Antimicrobial Surface Obtained by Chemical Grafting of Microfibrillated Cellulose in Aqueous Solution Limiting Antibiotic Release.

Contact active surfaces are an innovative tool for developing antibacterial products. Here, the microfibrillated cellulose (MFC) surface was modified with the β-lactam antibiotic benzyl penicillin in aqueous medium to prepare antimicrobial films. Penicillin was grafted on the MFC surface using a suspension of these nanofilaments or directly on films. Films prepared from the penicillin-modified MFC were characterized by Fourier transform infrared spectroscopy, contact angle measurements, elemental analysis, and X-ray photoelectron spectroscopy and tested for antibacterial activity against the Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. Penicillin-grafted MFC films exhibited successful killing effect on Gram-positive bacteria with 3.5-log reduction whereas bacteriostatic efficiency was found in penicillin-grafted MFC suspension. The zone of inhibition test and leaching dynamic assay demonstrated that penicillin was not diffused into the surrounding media, thus proving that the films were indeed contact active. Thus, penicillin can be chemically bound to the modified substrate surface to produce promising nonleaching antimicrobial systems.

Study of Alkalization to the Crystallinity and the Thermal Behavior of Arenga Pinnata “Ijuk” Fibers-Based Polylactic Acid (PLA) Biocomposite

The pollution due to non-degradable material such as plastics, has led to studies about the development of environmental-friendly materials. Because of natural sources-based materials and their biodegradability, polylactid acid (PLA) and ijuk fiber are interesting to be modified into a composite. Furthermore this study is also expected to reduce the impact of environmental problems. Surface modification of ijuk fiber through alkalinization, was aimed to enhance compatibility between the ijuk fiber and the PLA, in order to improve properties of the composite such as crytallinity and thermal behavior. To investigate in detail about this modification, this research also studied effect of the alkalinized ijuk fiber and the PLA composition to the crystallinity and the thermal behavior of the composites. The experimental results were investigated by FTIR to qualitatively analyze compounds content in the ijuk fiber before and after alkalinization, DSC and TGA to study crystallinity and thermal stability behavior of the composite, respectively and FE-SEM to observe morphological behavior like compatibility between the ijuk fiber and the PLA. The FE-SEM observation showed that alkalinization of the ijuk fiber led to wettability enhancement between the ijuk fiber and the PLA. This may be caused by annihilating lignin and hemicellulose. Furthermore this treatment leads to expose micro-fibril cellulose (MFC) in the ijuk fiber and then to enhancement of bonding affinity with the PLA. This phenomenon gives a possibility for the PLA in the composite to increase its crystallinity due to nucleating effect of crystalline parts in the MFC. DSC measurements show that addition of the alkalinized ijuk fiber tends to increase the crystallinity of PLA in the composites.Keywords: alkalization, Arenga Pinnata, compatibility, crystallinity, PLA, thermal stability

Batch foaming poly(vinyl alcohol)/microfibrillated cellulose composites with CO2 and water as co‐blowing agents

ABSTRACTWe studied the foaming behavior of poly(vinyl alcohol) (PVOH) and microfibrillated cellulose (MFC) composites in a batch process using supercritical carbon dioxide (scCO2) and water as co‐blowing agents. In PVOH/MFC composites, water is an economical plasticizer. It not only suppresses the potential thermal degradation of PVOH but also extends the processing window. A uniform cell structure and a high cell density were achieved in the PVOH/MFC foams. The results showed that cell density was increased by increased water content. Further, the MFC contained both micro‐ and nano‐sized fibers. These created numerous heterogeneous nucleation sites and caused local pressure variations. However, cell density decreased when the MFC was overdosed. Due to the high crystallinity that then developed around the MFC, the gas content was too low, and the stiffness was too high. The experimental results also showed that the cell morphology and density could both be controlled by the water and the MFC content. The effects of the foaming temperature and pressure on the cellular morphology of the PVOH/MFC composite foams were examined systematically. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42551.

High-consistency milling of oxidized cellulose for preparing microfibrillated cellulose films

Microfibrillated celluloses (MFCs) with a high elongation potential were fabricated from periodate–chlorite oxidized cellulosic fibers (anionic charge density of 1.75 mmol/g) using high consistency milling conducted at a solids content of 7.5–15 % with a PFI mill. MFC gels were obtained after 5000 milling revolutions and after 30,000 revolutions MFCs with lateral dimension ranging from 10 to 100 nm and length up to micron-scale were obtained from all samples according to scanning electron microscopy imaging. The crystallinity in terms of crystalline indexes of MFCs was similar to untreated pulp (~65 %). Free-standing films produced from the MFC samples (milled for 30,000 revolutions) had the ultimate tensile strength and Young’s modulus of 61–115 MPa and 8–11 GPa, respectively. The films also showed very high stretchability potential in terms of strain at break values of 6.8–15.9 %. Thus, the results suggest that high consistency milling with high production capacity and decreased energy consumption can potentially be used to fabricate MFC with high mechanical performance for bulk applications.

Cationic amphiphilic microfibrillated cellulose (MFC) for potential use for bile acid sorption

In this work, Micro-fibrillated Cellulose (MFC) was cationically modified by quaternary ammonium groups with different chemical structures aiming to improve the sorption capacity to bile acid. The in-vitro bile acid sorption was performed by investigating various factors, such as quaternary ammonium group content and length of its alkyl substituent of the modified cationic MFC (CMFC), ionic strength, initial concentration and hydrophobicity of bile acid. The results showed that the sorption behavior of the modified CMFC was strongly influenced by the quaternary ammonium group content and the lengths of its alkyl substituent, the sorption capacity for the modified CMFC with a C18 alkyl substituent, was approximately 50% of that of Cholestyramine. The experimental isotherm results were well fitted into the Temkin model. The effect of salts in the solution was smaller for the bile acid sorption onto the hydrophobic CMFC than the CMFC. It was also found that the binding capacity of CMFC was higher for more hydrophobic deoxycholate in comparison with cholate.

Effect of cellulose nano fiber (CNF) on fatigue performance of carbon fiber fabric composites

The effect of cellulose nano fibers (CNF): micro-fibrillated cellulose and bacteria cellulose fibers were investigated on the fatigue life of carbon fiber (CF) fabric/epoxy (EP) composites. Epoxy used as the matrix was physically modified with CNF in advance before fabricating the laminates. The high cycle fatigue strength was significantly improved at 0.3wt% CNF. There exists an appropriate CNF content which makes the fatigue life longest. An increase of adhesive strength between CF and matrix results due to physical modification with CNF. The adhesive strength much increases with increasing the CNF content. Almost no interfacial debonding occurs at 0.8wt% CNF content when CF breakage takes place. On the other hand, some debonding occurs along CFs from the breaking point at 0.3wt% CNF. Debonding is more significant in the case of no CNF addition to the matrix. An appropriate interfacial strength brought at 0.3wt% CNF is the key of fatigue life extension.