Microcrystalline Cellulose Fibers Research Articles

Development of polylactic acid based antimicrobial food packaging films with N-halamine modified microcrystalline cellulose

Bio-based “green” films with superior antimicrobial activity were developed from polylactic acid (PLA) and cyclic N-halamine 1-chloro-2,2,5,5-tetramethyl-4-imidazolidinone (MC) grafted microcrystalline cellulose (MCC) fibers (herein referred to as g-MCC). The structure of g-MCC was characterized by Fourier Transform Infrared (FT-IR) and Nuclear Magnetic Resonance (NMR) spectroscopy. Results indicated N-halamine MC was successfully grafted onto MCC fibers, with a grafting percentage of 10.24 %. The grafting improved compatibility between g-MCC and PLA, leading to an excellent dispersion of g-MCC in the film matrix, and a superior transparency of the g-MCC/PLA compared to that of the MCC/PLA films. Additionally, the enhanced compatibility the g-MCC/PLA films produced better mechanical properties including mechanical strength, elongation at break and initial modulus than those of both MCC/PLA and MC/PLA composites. With N-halamine, g-MCC/PLA completely inactivated all the inoculated Escherichia coli and Staphylococcus aureus within 5 and 30 min of contact, respectively. More importantly, the migration test showed that the oxidative chlorine of g-MCC/PLA was highly stable than that of MC/PLA films, providing a long-term antimicrobial activity. Finally, preservation test conducted on fresh bread slices further demonstrated its promising applications in the food industry.

A study on the prospects of vacuum gamma irradiation to enhance crosslinking for 3D-Printing PLA/MCC biocomposite filaments

3D-printing or Additive Manufacturing (AM) has been growing as a rapid manufacturing process for many different applications, with Poly (Lactic Acid) as one of the most used materials for 3D-printing. PLA shows great promise for many applications to achieve the goals of the SDGs due to its biodegradability and biocompatibility but lacks when it comes to mechanical strength and thermal resistance. In this study, microcrystalline cellulose (MCC) fibers were introduced as a reinforcement to PLA. The biocomposite filaments were irradiated in a vacuum to enhance the crosslinking. Gamma-ray irradiation in a vacuum has successfully shown signs of crosslinking by increasing the tensile strength and thermal stability of the biocomposite, indicating an enhancement for PLA/MCC for various applications. On the other hand, changes in thermal properties also indicated that irradiation may reduce the processability of the composite, so it is necessary to study the conditions under which the mechanical properties and processability are compatible.

Analysis of cellulose synthesis in a high-producing acetic acid bacterium Komagataeibacter hansenii

Bacterial cellulose (BC) represents a renewable biomaterial with unique properties promising for biotechnology and biomedicine. Komagataeibacter hansenii ATCC 53,582 is a well-characterized high-yield producer of BC used in the industry. Its genome encodes three distinct cellulose synthases (CS), bcsAB1, bcsAB2, and bcsAB3, which together with genes for accessory proteins are organized in operons of different complexity. The genetic foundation of its high cellulose-producing phenotype was investigated by constructing chromosomal in-frame deletions of the CSs and of two predicted regulatory diguanylate cyclases (DGC), dgcA and dgcB. Proteomic characterization suggested that BcsAB1 was the decisive CS because of its high expression and its exclusive contribution to the formation of microcrystalline cellulose. BcsAB2 showed a lower expression level but contributes significantly to the tensile strength of BC and alters fiber diameter significantly as judged by scanning electron microscopy. Nevertheless, no distinct extracellular polymeric substance (EPS) from this operon was identified after static cultivation. Although transcription of bcsAB3 was observed, expression of the protein was below the detection limit of proteome analysis. Alike BcsAB2, deletion of BcsAB3 resulted in a visible reduction of the cellulose fiber diameter. The high abundance of BcsD and the accessory proteins CmcAx, CcpAx, and BglxA emphasizes their importance for the proper formation of the cellulosic network. Characterization of deletion mutants lacking the DGC genes dgcA and dgcB suggests a new regulatory mechanism of cellulose synthesis and cell motility in K. hansenii ATCC 53,582. Our findings form the basis for rational tailoring of the characteristics of BC.Key points• BcsAB1 induces formation of microcrystalline cellulose fibers.• Modifications by BcsAB2 and BcsAB3 alter diameter of cellulose fibers.• Complex regulatory network of DGCs on cellulose pellicle formation and motility.

Manihot esculenta tuber microcrystalline cellulose and woven bamboo fiber-reinforced unsaturated polyester composites: mechanical, hydrophobic and wear behavior

In this research Manihot esculenta (cassava) tuber stem microcrystalline cellulose (MCC) and woven bamboo fiber (WBF) reinforced unsaturated polyester (UP) composites are prepared and tested. The main aim of this study was to synthesis the microcrystalline cellulose from Manihot esculenta tuber stem and investigate the mechanical, wear and hydrophobic properties of UP resin composite made using MCC and WBF. The laminated composites were prepared by the hand layup method and characterized according to ASTM standards. According to the results, the composite containing 40 vol% of WBF increased the tensile strength and modulus, flexural strength and modulus, interlaminar shear strength, Izod impact as well as hardness by 39%, 10%, 42%, 27%, 1%, 91%, and 1%, respectively as compare to pure polyester resin composites. In comparison to all composites, the composite with 4 vol% of MCC exhibits the lowest sp. wear rate of 0.011 mm3/Nm. The water absorption contact angle indicated that all composite designations had a wider contact angle of more than 70°, which indicates a stronger hydrophobicity of composites. The SEM fractography reveals improved bonding and toughness for 4 vol% of MCC and WBF reinforced UP composites. Such mechanically stronger, wear resistance, as well as high hydrophobic composites, could be used in aerospace, automobile, defence and industrial sector.

The mechanical and physical properties of microcrystalline cellulose (MCC)/sisal/PMMA hybrid composites for dental applications

The study on polymethyl methacrylate (PMMA)-based composites in dental applications has gained much interest in recent years, resulting in many exciting studies worldwide. In those research, various filler types of reinforcing PMMA have been studied extensively. This study combines the microcrystalline cellulose (MCC) particles (0, 1, 2, 3, 5 vol.%) and sisal fiber to strengthen PMMA. We investigate their effects on the flexural, impact, hardness, compressive strength, water absorption, and thermal properties of (MCC)/sisal/PMMA hybrid composites. Scanning electron microscopy (SEM), universal testing machine (UTM), hardness Vickers, thermogravimetry analysis (TGA), and ANSYS Workbench 2022 R1 software are utilized to characterize the properties of the composites. X-ray diffraction (XRD) is used to characterize the degree of crystallinity of MCC and sisal fiber. Adding MCC to alkali-treated sisal/PMMA decreases the flexural and impact strengths but increases the hardness. Adding 1 and 2 vol.% MCC produces maximum flexural and impact strength and hardness values. Simulation on a composite added with 1% MCC by applying a full force load of 14.4 N yields compressive strength of 42.56 MPa. Thermal stability of all composites with and without MCC shows similarity until 250 °C but gradually degrades at over 250 °C, particularly for composites with MCC. Besides, as the addition of MCC increases, the water absorption also increases, with the lowest value of 37.54 μg mm−3 obtained by the composite added with 1 vol.% MCC, which is within the range of the standard dental materials.

L-lysine and dietary fiber improve the physicochemical properties of sausage without added phosphate and reduced salt levels

The demand for clean label foods has driven research in the meat product sector. The objective of this study was to evaluate the effect on the physicochemical properties of adding L-lysine, wheat fiber (WTF) and microcrystalline cellulose (MCC) in sausage without the addition of sodium tripolyphosphate (STPP) and with reduced salt levels. Eight treatments were produced in total. Three control treatments were: CON1 - 0.5 % sodium tripolyphosphate and 2 % salt; CON2 - without STPP and 2 % salt; CON3 - without STPP and 1 % salt. Five other treatments were carried out without STPP and 1 % of salt: LYS - 0.8 % L-lysine; WTF - 2 % wheat fiber; MCC - 2 % microcrystalline cellulose fiber; LYSWTF - 0.8 % L-lysine and 2 % wheat fiber; LYSMCC - 0.8 % L-lysine and 2 % microcrystalline cellulose fiber. L-lysine and wheat fiber provided good emulsion stability for sausages. L-lysine and MCC increased the yield of the products. Microcrystalline cellulose increased the red color value (a*) of sausages. The intensity of the yellow color value (b*) was significantly affected by the removal of STPP and the reduction of salt levels, but L-lysine and MCC improved this parameter, providing similar results to CON1. Adding of L-lysine and dietary fiber increased hardness in sausages without added STPP and with salt reduction. L-lysine and wheat fiber are promising for reformulating emulsified meat product without phosphate added and with reduced salt levels due to lipid oxidation control and improvement in emulsion stability.

Controlling cellulose feedstock size allows for modification of cellulose-based carbon-based solid acid size

Carbon-based solid acids (CSA) have grown in popularity in recent years owing to their strong catalytic activity, thermal stability, and reusability. The size effect has a significant influence on the catalytic activity of carbon-based solid acids in heterogeneous catalysts. The impacts of raw material size on the shape, sulfonation degree, and catalytic activity of produced carbon-based solid acids were examined in this article. Various sizes of microcrystalline cellulose (MCC), cellulose nanocrystals (CNCs), and cotton fiber pulp (CP) were used as carbon sources in a simple carbon-sulphonation method to synthesize carbon-based solid acids. The produced CSA has a high concentration of sulphonic acid groups, as well as hydroxyl and carboxyl groups, and exhibits remarkable catalytic activity for the conversion of xylan to xylose. The solid acids generated from MCC have the most homogeneous shape, the greatest degree of sulphonation, and the highest catalytic activity. The conversion rate of xylan hydrolysis to xylose was up to 58.8% under ideal reaction conditions (150 °C, 4 h), and the catalyst retained almost its initial level of activity after five cycles with no appreciable deactivation.Graphical abstract

Pyrolysis Decomposition Kinetics of Microcrystalline Cellulose and Curaua Fiber: Insight of Reaction Models by Using Vyazovkin Method

ABSTRACT This paper provides a full understanding of the pyrolysis mechanism of plant biomass (curaua) and cellulose – two materials that involve complex degradation stages. The chemical/physical reactions occurring in the corresponding mass loss stages are described in detail for each material. Multi-step degradation stages are identified by using Vyazovkin and Flynn–Wall–Ozawa methods and the individual contribution are discussed in terms of the chemical and physical steps involved in the process. The determination of multi-stages processes are rapidly determined applying an easy-to-use method as a first approach. We expect that this study helps to develop an understanding of the thermal degradation for future complex materials as well as to establish the initial guesses and to give an insight into the overall biomass decomposition. Final results can help to design of pyrolysis reactor and to develop new kinetic approaches.

The Effect of Chemical and High Pressure Homogenization Treatment Conditions on the Morphology of Nanocellulose

Nanocellulose was fabricated from empty fruit bunch (EFB)-derived microcrystalline cellulose (MCC) through combined acid hydrolysis with sulfuric and hydrochloric acids and high-pressure homogenization. The effects of acid-to-MCC ratio and the number of high-pressure homogenizations passes on nanoparticle morphology were investigated. The MCC was treated with different concentrations of sulphuric acid (5% to 25%) through the hydrolysis process. The diameter of the acid treated MCC fibres was reduced to roughly 8 m in Scanning Electron Microscopy (SEM) micrographs, while the length of the fibres was reduced by several microns when compared to untreated fibres. The suspensions of MCC were passed through a high pressure homogenizer at a constant pressure of 800 bar with passing times of 10, 20 and 30 cycles. After 30 cycles, the final suspension of nanocellulose (NC) became cloudy. This was a visual indication that the particles were converted to smaller sizes and were less entangled. Field Emission Scanning Electron Microscopy (FESEM) results showed that the particle size of nanocellulose ranged between 18 to 20 nm. As a result, the combination of sulphuric acid hydrolysis and high-pressure homogenization operations could be used as an efficient chemo29 mechanical technique for producing nanocellulose from various cellulosic sources.

Features of water vapor sorption by cellulose materials

In this research, the sorption of water vapor (WV) by various cellulose samples (microcrystalline cellulose, cotton cellulose, Kraft pulp, mercerized cellulose, and rayon fibers) has been studied. The sorption isotherms of WV for various samples have a sigmoid shape. To describe such isotherms, various models have been proposed, including mono- and multimolecular adsorption, formation of hydrates and solid solutions, as well as mixed models combining various sorption mechanisms. After critical analysis of known models, the improved absorption model was proposed to explain the interaction of VW with cellulose samples. It was confirmed that crystallites are inaccessible for water, and therefore water molecules can be trapped only by polar groups of non-crystalline (amorphous) domains of cellulose materials. The developed model permitted obtaining the general absorption isotherm of water molecules in amorphous domains of cellulose. Moreover, the equation was derived, which describes both the general isotherm and isotherm of any semi-crystalline cellulose sample, when its crystallinity or amorphicity degree was pre-determined. Based on the proposed absorption model, various characteristics can be found, e.g., degrees of amorphicity and crystallinity, the maximum amount of absorbed water, the specific surface area of wet cellulose sample, the amount of capillary condensed water, etc.

Influence of Submicron Fibrillated Cellulose Fibers from Cotton on Hydration and Microstructure of Portland Cement Paste.

This paper reports the influence of submicron hydrophilic fibers on the hydration and microstructure of Portland cement paste. Submicron fibrillated cellulose (SMC) fibers was prepared by the acid hydrolysis of cotton fibers in H2SO4 solution (55% v/v) for 1.5 h at a temperature of 50 °C. The SMC fibers were added into cement with a dosage of 0.03 wt.%, and the effect of SMC on the hydration and microstructure of cement paste was investigated by calorimeter analysis, XRD, FT-IR, DSC-TG, and SEM. Microcrystalline cellulose (MCC) fibers were used as the contrast admixture with the same dosage in this study. The results show that the addition of SMC fibers can accelerate the cement hydration rate during the first 20 h of the hydration process and improve the hydration process of cement paste in later stages. These results are because the scale of SMC fibers more closely matches the size of the C-S-H gel compared to MCC fibers, given that the primary role of the SMC is to provide potential heterogeneous nucleation sites for the hydration products, which is conducive to an accelerated and continuous hydration reaction. Furthermore, the induction and bridging effects of the SMC fibers make the cement paste microstructure more homogeneous and compact.

Effect of Fiber Loading on the Chemical, Structural and Mechanical Properties of 3D Printed Polylactic Acid/Abaca Microcrystalline Cellulose Composites

In an attempt to improve the physical properties of 3D printed poly lactic acid (PLA), this study aims to develop a microcrystalline cellulose fiber and observe the effects of fiber loading on the PLA/cellulose composites to the composition, crystallinity, morphology, and tensile properties of the resulting 3D printed material. Microcrystalline cellulose (MCC) have been extracted from indigenous raw abaca fibers and used as the fiber reinforcement for the PLA matrix. Composites of 1 and 3 wt% MCC fibers with PLA were processed using the twin-screw extruder to produce filaments. The resulting composite filaments were 3D printed utilizing the fused deposition modeling technology. FTIR, XRD, digital microscopy, and mechanical testing were used in characterizing the various 3D printed PLA/MCC composite. With the incorporation of cellulose, the PLA/MCC had up to 32% increase in tensile strength and 43% increase in modulus at just 3 wt% fiber loading due to the inherent high modulus of abaca cellulose. The MCC significantly influences the chemical, structural and mechanical properties of the 3D printed PLA/MCC composites.

Characterization of weathered MCC / nutshell reinforced composites

Microcrystalline cellulose (MCC) and nutshell fiber reinforced high-density polyethylene (HDPE) composites were exposed to accelerated weathering for total of 672 h. The effects of weathering exposure on the mechanical, surface and morphological properties of the composites were investigated. The results revealed that the weathering exposure caused a slight decrease on tensile and flexural strengths whilst the modulus of elasticity increased up to 62%. The MCC / nutshell reinforced composites had higher color changes and gloss loss than MCC reinforced composites. Addition of MCC and nutshell to HDPE composites increased surface roughness of samples. After the weathering, the polymer band intensities decreased due to the degradation. The SEM observations on the exposed composites are in accordance with the surface roughness of composites after weathering. The investigated properties of MCC/nutshell filled HDPE composites were less affected by weathering exposure than those of composites without nutshell.

Performance of reduced fat-reduced salt fermented sausage with added microcrystalline cellulose, resistant starch and oat fiber using the simplex design

The search for ingredients that improve technological and nutritional aspects of food has been intensified in recent years by both researchers and industry. Thus, the aim of this study was to evaluate fermented sausages with simultaneous reduction of fat (25%) and salt (25% KCl; 75% NaCl) using up to 2% of three different dietary fiber: microcrystalline cellulose (MCC), resistant starch (RS) and oat fiber (OF). Technological and sensory evaluations used the simplex-centroid mixture design. The dietary fiber added did not affect the weight loss, pH values and sensory acceptance. Models were obtained for water activity, lactic acid bacteria, hardness, chewiness and TBARS values. When included in combination the three dietary fiber helped reduce water activity, inclusion of MCC increased the population of lactic acid bacteria, and inclusion of OF with MCC demonstrated an antioxidant effect and improved hardness and chewiness. These dietary fibers are ingredients that can contribute to the development of reduced fat – reduced salt fermented sausage.

Hybrid Cellulose-Basalt Polypropylene Composites with Enhanced Compatibility: The Role of Coupling Agent.

This study deals with the development and optimization of hybrid composites integrating microcrystalline cellulose and short basalt fibers in a polypropylene (PP) matrix to maximize the mechanical properties of resulting composites. To this aim, the effects of two different coupling agents, endowed with maleic anhydride (MA-g(grafted)-PP) and acrylic acid (AA-g-PP) functionalities, on the composite properties were investigated as a function of their amount. Tensile, flexural, impact and heat deflection temperature tests highlighted the lower reactivity and effectiveness of AA-g-PP, regardless of reinforcement type. Hybrid formulations with basalt/cellulose (15/15) and with 5 wt. % of MA-g-PP displayed remarkable increases in tensile strength and modulus, flexural strength and modulus, and notched Charpy impact strength, of 45% and 284%, 97% and 263%, and 13%, in comparison with neat PP, respectively. At the same time, the thermo-mechanical stability was enhanced by 65% compared to neat PP. The results of this study, if compared with the ones available in the literature, reveal the ability of such a combination of reinforcements to provide materials suitable for automotive applications with environmental benefits.

Influence of amorphous cellulose on mechanical, thermal, and hydrolytic degradation of poly(lactic acid) biocomposites

Eco-friendly materials such as poly(lactic acid) (PLA) and cellulose are gaining considerable interest as suitable substitutes for petroleum-based plastics. Therefore, amorphous cellulose (AC) was fabricated as a new reinforcing material for PLA biocomposites by modifying a microcrystalline cellulose (MCC) structure via milling. In this study, the mechanical properties, thermal properties, and degradability of PLA were analysed to compare the effects of both MCC and AC on PLA. The tensile and impact properties improved at an optimum value with AC at 8 wt% and 4 wt% fibre loading, respectively. Notably, a scanning electron micrograph analysis revealed improved AC fibre–matrix adhesion, compared with MCC fibre–matrix adhesion, as well as excellent interaction between AC and PLA. Both MCC and AC improved the hydrolytic degradation of PLA. Moreover, the biocomposites with AC exhibited superior degradation when the incorporation of AC improved the water absorption efficiency of PLA. These findings can expand AC applications and improve sustainability.

The effects of microcrystalline cellulose as a dietary component for lactating dairy cows

Microcrystalline cellulose (MCC) has several applications in food and pharmaceutical industries but the nutritional value for dairy cows and effects on in vivo digestion are not known. A feeding experiment was conducted using 24 dairy cows. The cows were offered MCC originating from unbleached softwood kraft pulp at 0, 10 or 100 g per kg diet dry matter (DM) to replace barley grain in the diet. The total daily DM intake was on average 25.6 kg and not significantly affected by the diet. Positive effects on rumen fermentation could not be demonstrated in a feeding situation where total mixed ration and a concentrate proportion of 0.50 on DM basis was used. Diet organic matter digestibility was not affected by MCC inclusion but fibre digestibility improved and the additional MCC fibre was virtually completely digested. The production potential of MCC was lower than that of barley grain as daily yields of energy-corrected milk, milk fat and protein, and milk protein concentration decreased when MCC replaced barley grain in the diet. Based on these results, MCC is not recommended as a dietary component for high-yielding dairy cows.

Reinforcement Efficiency of Cellulose Microfibers for the Tensile Stiffness and Strength of Rigid Low-Density Polyurethane Foams.

Rigid low-density closed-cell polyurethane (PU) foams are widely used in both thermal insulation and structural applications. The sustainability of PU foam production can be increased by using bio-based components and fillers that ensure both enhanced mechanical properties and higher renewable material content. Such bio-based foams were produced using polyols derived from rapeseed oil and microcrystalline cellulose (MCC) fibers as filler. The effect of MCC fiber loading of up to 10 wt % on the morphology, tensile stiffness, and strength of foams has been evaluated. For estimation of the mechanical reinforcement efficiency of foams, a model allowing for the partial alignment of filler fibers in foam struts was developed and validated against test results. It is shown that although applying MCC fibers leads to modest gains in the mechanical properties of PU foams compared with cellulose nanocrystal reinforcement, it may provide a higher content of renewable material in the foams.

Microcrystalline cellulose, polylactic acid and polypropylene biocomposites and its morphological, mechanical, thermal and rheological properties

Modification of mechanical, morphological, thermal and rheological properties of the polymers via melt blending method has been an area of great interest. The present work describes the fabrication of microcrystalline cellulose (MCC) fibre with polylactic acid (PLA) and polypropylene (PP) blend by twin screw extruder to optimize melt processability of the PLA matrix. Compared to PLA, the tensile strength and percentage elongation of PLA80/19.9PP/0.1MCC biocomposites were reduced by ~32% and ~4%, respectively. No significant improvement was achieved in the Tg and Tc of the MCC based biocomposites. The PLA spherulite growth rate in PLA80/19.5PP/0.5MCC biocomposite was enhanced to 2.91 μm/min compared to pure PLA matrix (2.53 μm/min). The storage modulus of PLA was increased from low to high frequency while complex viscosity of PLA and its biocomposites showed shear thinning behaviour at a frequency range of 0.1–100 rad/s. Both PLA and PP, showed hydrophobic characteristics. Incorporation of MCC fibres resulted in the decrease in water contact angles of the biocomposites to ~62°. Thus, it can be concluded that blending of MCC fibres results in considerable changes in the properties of the PLA and PP polymers.

Effect of microcrystalline cellulose [MCC] fibres on the morphological and crystalline behaviour of high density polyethylene [HDPE]/polylactic acid [PLA] blends

The present study describes the fabrication and characterization of eco-friendly composites based on high density polyethylene (HDPE), poly (lactic acid) (PLA) with microcrystalline cellulose (MCC) fibres via melt extrusion followed by injection moulding. The morphology of PLA in both HDPE/PLA blends and HDPE/MCC fibres composites was irregular and immiscible. The tensile strength at max load and % elongation at break of all polyblend composites were reduced to ~17%, ~15%, and ~84%, ~89% than pure HDPE matrix, respectively. The toughness of HDPE and its polyblend composites were decreased to ~92% and ~91%, respectively. As higher number indicates greater resistance, the hardness of HDPE was improved by ~7% and ~10% after adding PLA followed by MCC fibres. As revealed from DSC analysis, the crystallinity of composites was considerably influenced by the MCC fibres content due to the transcrystallization effect. The crystallinity of HDPE/PLA with MCC fibres polyblend composites was decreased by ~41% as compared to the HDPE matrix because of disorientation of fibres as seen in X-ray diffraction analysis. Eventually, the results revealed that the presence or absence of MCC fibre loading had significant effects on the mechanical, morphological, and thermal properties of HDPE/PLA blends.