Addition Of Cellulose Nanocrystals Research Articles

Tubular PAN/CNC thin film nanocomposite (TFN) pressure retarded osmosis (PRO) membrane: fabrication and preliminary evaluation in desalination process

The pressure retarded osmosis (PRO) process requires high performance, high flux, high rejection, and resistant membranes under harsh conditions. Since conventional phase-inversion membranes are insufficient to permit the required water flux, alternative membrane fabrication methods need to be developed. Many studies have recently been carried out to fabricate strong enough nanofiber PRO membranes resistant to higher pressure while providing high flux and high rejection rates. This work aims to fabricate tubular nanofiber PRO membranes by the electrospinning technique. In the study, cellulose nanocrystals (CNCs) were added to polyacrylonitrile (PAN) polymer solution to fabricate nanocomposite nanofiber PRO membranes. According to the scanning electron microscopy (SEM), FT-IR, dynamic mechanical analysis, porometer, and contact angle analysis results, it is concluded that PAN and CNCs provided a complete mixture, and the addition of CNCs increased the mechanical strength in the PAN membranes, which is the crucial phenomena in PRO applications. In this study, the newly fabricated membrane achieves a higher PRO water flux of 405.38 LMH using 1 M NaCl and a DI as feed water. The corresponding salt flux is found as 2.10 gMH, which is higher than our previous study. The selectivity of the reversed flux represented by the ratio of the water flux to the reversed salt flux (Jw/Js) was able to be kept as high as 193.03 L/g for PRO operation. As far as we know, the performance of the work-developed membrane in this study has shown better performance than all PRO membranes reported in the literature previously.Graphic abstract

Construction and Nanostructure of Chitosan/Nanocellulose Hybrid Aerogels.

Biomass aerogels have received extensive attention due to their unique natural characteristics. However, biomass-based chitosan aerogels are often confronted with the traditional issue concerning a weak skeleton structure, namely, the corresponding huge shrinkage for chitosan aerogels in the stage from the final gel to the aerogel. Herein, we put forward a new approach to enhance chitosan aerogels by introducing natural biomaterial cellulose nanocrystal (CNC). CNC is applied to connect/cross-link chitosan chains to form its networking construction through supramolecular interaction/physical entanglement, eventually realizing the enhancement of the chitosan aerogel network structure. Chitosan aerogels modified with CNC exhibit a high specific surface area of 578.43 cm2 g-1, and the pore size distribution is in the range of 20-60 nm, which is smaller than the mean free path of gas molecules (69 nm), triggering a "no convection" effect. Hence, the gaseous heat transfer of chitosan aerogel is effectively suppressed. Chitosan aerogels with the addition of CNC show an excellent thermal insulation property (0.0272 W m-1 K-1 at ambient condition) and an enhanced compressive strength (0.13 MPa at a strain of 3%). This improvement method of chitosan aerogel in enhancing the skeleton structure aspect provides a new kind of idea for strengthening the nanoscale morphology structure of biomass aerogels.

“Faba bean protein films reinforced with cellulose nanocrystals as edible food packaging material”

In the present work, transparent films were obtained by the solution casting method from faba bean protein isolate (FBP), reinforced with different cellulose nanocrystals (CNCs) content (1, 3, 5 and 7 wt%), obtained by acid hydrolysis of pine cone, and using glycerol as plasticizer. The influence of different CNCs loadings on the mechanical, thermal, barrier, optical, and morphological properties was discussed. Microstructurally, the FTIR and FESEM results corroborated the formation of intramolecular interactions between the CNCs and proteins that lead to more compact and homogeneous films. These interactions had a positive influence on the mechanical strength properties, which is reflected in higher tensile strength and Young's modulus in reinforced films with respect to the control film, resulting in stiffer films as the CNCs content increases. Thermal stability of the FBP films was also improved with the presence of CNCs, by increasing the characteristic onset degradation temperature. In addition, the linkages formed between the CNCs, and proteins reduced the water affinity of the reinforced films, leading to a reduction in their moisture content and water solubility, and an increase in their water contact angle, obtaining more hydrophobic films as the CNCs content in the matrix increased. The addition of CNCs in the FBP film also considerably improved its barrier properties, reducing its water vapour transmission rate (WVTR) and oxygen transmission rate (OTR). The present work shows the possibility of obtaining biobased and biodegradable films of CNC-reinforced FBP with improved mechanical, thermal and barrier properties, and low water susceptibility, which can be of great interest in the food packaging sector as edible food packaging material.

SUSTAINABLE CELLULOSE NANOCRYSTAL REINFORCED CHITOSAN/HPMC BIO-NANOCOMPOSITE FILMS CONTAINING MENTHOL OIL AS PACKAGING MATERIALS

There is a growing demand to develop biodegradable composite films, with enhanced water resistance, antimicrobial activity, high mechanical properties and low oxygen permeability. In the present study, chitosan/hydroxypropyl methylcellulose (HPMC) films reinforced with cellulose nanocrystal (CNC) and containing menthol oil were prepared for food packaging applications. Menthol oil was selected due to its antibacterial properties, as well as relatively low cost and wide availability. CNC was prepared from bagasse via acid degradation. The bio-composites were prepared through a simple and versatile solution mixing and casting method. The morphology, chemical composition, water absorption, mechanical properties and antibacterial activity of the films were investigated. FTIR spectra were used to evaluate the film structure in terms of the interactions between components. Data showed that the addition of CNC improved the mechanical properties of the formed films and the menthol oil enhanced their antibacterial properties. HPMC and HPMC/CNC reduced the water absorption of the pure chitosan membrane from 70% to 22% and 9-11% by weight, respectively, which makes these constituents a good alternative for producing packaging.

Preparation of cellulose nanocrystals from deinked waste newspaper and their usage for papermaking

Cellulose nanocrystals (CNC) were successfully prepared from waste newspapers through a simple pretreatment and hydrolysis process. The Fourier transform infrared spectroscopy (FTIR) result for the CNC suggested that no new chemical bonds were formed during the preparation of CNC. X-ray diffraction results indicated that the crystallinities of the deinked and untreated waste newspapers were 66% and 73.8%, respectively. Greater smoothness of the deinked waste newspapers fibers could be clearly observed by scanning electron microscope (SEM), which was attributed to the removal of ink from the chemical treatment. The transmission electron microscopy (TEM) and atomic force microscopy (AFM) results of the CNC revealed a needle-like natural fiber with a length of 300 nm to 600 nm, a diameter of 10 nm to 30 nm, and an aspect ratio in the 10 to 60 range. The obtained CNC particles were found to improve the physical properties of paper sheets, specifically that of the tear, tensile, and burst indices. The maximum increase in the physical properties was achieved with a 5.5% CNC addition.

Bio-nanocomposites based on compatibilized poly(lactic acid) blend-reinforced agave cellulose nanocrystals

Enhancing the mechanical, thermal, and degradation properties of a poly(lactic acid) (PLA) blend without deteriorating its other useful features was the goal of this work. The isolation of cellulose nanocrystals (CNCs) from Agave angustifolia fibers was carried out, and the properties of the bio-nanocomposites comprising these CNCs were evaluated, which included PLA, natural rubber (NR), and liquid NR (LNR). Transmission electron microscopy and zeta potential analysis confirmed the successful isolation of CNCs from agave fibers after several chemical treatment steps. The effects of different CNC loadings on the properties of the bio-nanocomposites were investigated using tensile tests, thermal analysis, morphological analysis, and water absorption tests. Bio-nanocomposites containing 5 wt% and 7.5 wt% CNC had the optimal tensile modulus and strength, respectively. Different levels of CNC did not noticeably affect the thermal stability of the bio-nanocomposites, although the thermogram curves increased slightly as CNC content increased. The addition of CNC at different loadings affects the crystallization rate of PLA blend. The water absorption capacity increased as CNC level increased, and 5 wt% CNC gave rise to the highest water absorption. The four-component bio-nanocomposites created in this study provided an alternative for producing new green materials with tunable physical, mechanical, and thermal properties.

Polypropylene/ethylene propylene diene monomer/cellulose nanocrystal ternary blend nanocomposites: Effects of different parameters on mechanical, rheological, and thermal properties

AbstractIn the present study, the effect of dynamic vulcanization, mixing sequence, and cellulose nanocrystal (CNC) content on mechanical, rheological, and thermal properties of the polypropylene/ethylene propylene diene monomer (PP/EPDM/CNC) ternary blend‐nanocomposites was investigated. Significant reduction in tensile and yield strengths occurred for the un‐vulcanized PP/EPDM blend compared to PP. Vulcanization and adding CNC have compensated for the decrease in tensile and yield strengths of the un‐vulcanized blend. The tensile and yield strengths of the vulcanized samples had almost a slight uptrend by adding CNC. Elongation at break for both nanocomposites types had slight changes compared to that of PP/EPDM‐thermoplastic vulcanizates and all of them were approximately in the range of 600%–700%. Adding CNC before or after vulcanization had the same effect on the trend of Young's modulus and the higher the amount of CNC, the greater the increase in Young's modulus. Incorporating and increasing the amount of CNC improved the impact strength of all samples, especially when added after vulcanization. Rheological measurements showed that vulcanization of PP/EPDM resulted in frequency independence of storage modulus and a more sharp increment in Complex viscosity. Also, the more CNC content, the more dramatic changes occurred in complex viscosity, especially in DV‐CNC nanocomposites. Differential scanning calorimeter analysis showed that all samples had higher crystallinity which was more significant for Dynamic vulcanization (DV)‐CNC nanocomposites. Scanning electron microscope images also indicated that the addition of CNC increased fracture surface roughness for all samples ignoring their preparation sequence.

Designing Biodegradable and Active Multilayer System by Assembling an Electrospun Polycaprolactone Mat Containing Quercetin and Nanocellulose between Polylactic Acid Films.

The design of multilayer systems is an innovative strategy to improve physical properties of biodegradable polymers and introduce functionality to the materials through the incorporation of an active compound into some of these layers. In this work, a trilayer film based on a sandwich of electrospun polycaprolactone (PCL) fibers (PCLé) containing quercetin (Q) and cellulose nanocrystals (CNC) between extruded polylactic acid (PLA) films was designed with the purpose of improving thermal and barrier properties and affording antioxidant activity to packaged foods. PCLé was successfully electrospun onto 70 µm-thick extruded PLA film followed by the assembling of a third 25 µm-thick commercial PLA film through hot pressing. Optical, morphological, thermal, and barrier properties were evaluated in order to study the effect of PCL layer and the addition of Q and CNC. Bilayer systems obtained after the electrospinning process of PCL onto PLA film were also evaluated. The release of quercetin from bi- and trilayer films to food simulants was also analyzed. Results evidenced that thermal treatment during thermo-compression melted PCL polymer and resulted in trilayer systems with barrier properties similar to single PLA film. Quercetin release from bi- and trilayer films followed a similar profile, but achieved highest value through the addition of CNC.

Role of in situ added cellulose nanocrystals as rheological modulator of novel waterborne polyurethane urea for 3D-printing technology

Cellulose nanocrystals (CNC) have been studied as rheological modulator in order to improve the printing performance of a novel polycaprolactone-polyethylene glycol (PCL-PEG) waterborne polyurethane urea (WBPUU) based ink for direct ink writing 3D-printing technology. The cellulose nanocrystals are chemically bonded to the WBPU, since they were added during the synthesis of a WBPUU, in order to tune the rheological properties of the ink and thus, improve the printing performances. The WBPUU-CNC inks have been extensively characterized from the rheological viewpoint and have been subsequently used to print different pieces. To determine the capacity of the CNC to improve the printing performance of this type of inks, we establish the relationship between the rheological properties of the inks and their printing viability by an optimal window of compositions of the inks. Additionally, we have measured the mechanical and thermomechanical properties of printed WBPUU-CNC pieces to evaluate the effective reinforcement of in situ incorporated CNC in the WBPUU-CNC inks. The results showed that the addition of CNC accentuates the shear-thinning behaviour, presenting lower tan δ, especially at the lowest CNC contents compared with the matrix, which resulted in inks with excellent printable properties. Moreover, the shape fidelity is increased by the solid-like behavior due to the filler effect of CNC and confirmed by SEM images. Finally, a large increase in Young’s modulus and thermal and thermomechanical stability were observed on the printed pieces that contained only 0.5 wt% CNC compared to the matrix, suggesting the formation of effective interactions between CNC and WBPUU, as corroborated by FTIR, that lead to a greater reinforcement.

Fabrication and Characterization of Chitosan/Cellulose Nanocrystal/Glycerol Bio-Composite Films.

Cellulose nanocrystal (CNC)-reinforced bio-composite films containing glycerol were produced using the solution casting technique. The influences of the addition of CNC (2, 4, and 8 wt%) and glycerol (10, 20, and 30 wt%) on the properties of the bio-composite films were studied in the present work. The resulting films were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and thermogravimetry analysis (TGA), and according to their tensile, water absorption, and light transmission behavior. The introduction of 4 wt% CNC into the chitosan film did not affect the thermal stability, but the presence of 20 wt% glycerol reduced the thermal stability. The addition of 4 wt% CNC to the chitosan film increased its tensile strength, tensile modulus, and elongation at break by 206%, 138%, and 277%, respectively. However, adding more than 8 wt% CNC resulted in a drastic reduction in the strength and ductility of the chitosan film. The highest strength and stiffness of the chitosan bio-composite film were attained with 4 wt% CNC and 20 wt% glycerol. The water absorption and light transmission of the chitosan film were reduced dramatically by the presence of both CNC and glycerol.

Bamboo Fiber Based Cellulose Nanocrystals/Poly(Lactic Acid)/Poly(Butylene Succinate) Nanocomposites: Morphological, Mechanical and Thermal Properties.

The purpose of this work was to investigate the effect of cellulose nanocrystals (CNC) from bamboo fiber on the properties of poly (lactic acid) (PLA)/poly (butylene succinate) (PBS) composites fabricated by melt mixing at 175 °C and then hot pressing at 180 °C. PBS and CNC (0.5, 0.75, 1, 1.5 wt.%) were added to improvise the properties of PLA. The morphological, physiochemical and crystallinity properties of nanocomposites were analysed by field emission scanning electron microscope (FESEM), Fourier-transform infrared spectroscopy (FTIR) and X-ray diffractometry (XRD), respectively. The thermal and tensile properties were analysed by thermogravimetic analysis (TGA), Differential scanning calorimetry (DSC) and Universal testing machine (UTM). PLA-PBS blend shows homogeneous morphology while the composite shows rod-like CNC particles, which are embedded in the polymer matrix. The uniform distribution of CNC particles in the nanocomposites improves their thermal stability, tensile strength and tensile modulus up to 1 wt.%; however, their elongation at break decreases. Thus, CNC addition in PLA-PBS matrix improves structural and thermal properties of the composite. The composite, thus developed, using CNC (a natural fiber) and PLA-PBS (biodegradable polymers) could be of immense importance as they could allow complete degradation in soil, making it a potential alternative material to existing packaging materials in the market that could be environment friendly.

Effect of Cellulose Nanocrystal Addition on the Physicochemical Properties of Hydroxypropyl Guar-Based Intelligent Films.

As an important functional material in food industry, intelligent packaging films can bring great convenience for consumers in the field of food preservation and freshness detection. Herein, we fabricated pH-sensing films employing hydroxypropyl guar (HPG), 1-butyl-3-methylimidazolium chloride (BmimCl), and anthocyanin (Anth). Besides, the effects of adding cellulose nanocrystals (CNC) into the composite films upon the films’ structures and physicochemical properties are elucidated. The addition of CNC promoted more compact film structures. Moreover, CNC dramatically improved several properties of the pH-sensing films, including the distinguishability of their color changes, sensitivity to pH, permeability to oxygen and water vapor, solvent resistance, durability, and low-temperature resistance. These results expand the application range of pH-sensing films containing CNC in the fields of food freshness detection and intelligent packaging.

Eucalyptus spp. cellulose nanocrystals obtained by acid hydrolysis and ultrasound processing for structural strengthening in paper packaging

The objective of the present study was to obtain and evaluate the conditions of acid hydrolysis for cellulose nanocrystals (CNC) production, as well as to characterize its chemical and morphological structure and finally to realize and evaluate its application potential on paper as a structural reinforcing agent. From bleached cellulose, CNC is obtained by the acid hydrolysis process at 35, 40 or 45 °C for 25, 30 and 35 min. Then, an ultrasonic disruptor was used to reduce the particle size of the samples. The average particle diameters ranged from 203.4 to 66.4 nm, with yields from 57.57% to 30.14%. To obtain the paper, the cellulose is homogenized by mechanical stirring and is incorporated with starch (5%) and CNC (6, 12 and 18%). This suspension was vacuum filtered and the papers formed are pressed in a hydraulic press (Carver®) for five minutes under 5000kgf. The addition of CNC showed to be a good option for increasing physical and mechanical properties as they improved the paper quality. Papers produced and incorporated with 12% and 18% CNC have superior characteristics in mechanical tensile testing (8.1 MPa) compared to paper without CNC added. Optical properties were not influenced after the incorporation of CNC .

Thermoresponsive and Injectable Composite Hydrogels of Cellulose Nanocrystals and Pluronic F127.

Thermoresponsive amphiphilic Pluronic F127 triblock copolymer solutions have been widely investigated in smart biomaterial applications due to the proximity of its critical gel temperature to human body temperature. Meanwhile, cellulose nanocrystals (CNCs) have quickly become the focus of many drug delivery and tissue engineering applications due to their biocompatibility, abundance, ability to conjugate with drug molecules, and superior rheological properties. Herein, we investigate the phase behavior and thermo-rheological properties of the composite hydrogels containing cellulose nanocrystals (up to 5% by weight) and the temperature responsive Pluronic F127. Our results revealed an unprecedented role of CNC network formation on micellization and gelation behavior of the triblock copolymer. Linear and nonlinear rheological analysis suggest that at low and moderate nanocrystal loadings (1-3% by weight), the composite gel remarkably becomes softer and deformable compared to the neat Pluronic F127 gels. The softening effect results from the disruption of the close packed micelles by the rodlike CNCs. At high concentrations, however, the nanocrystals form their own network and the micelles are trapped within the CNC meshes. As a result, the original (neat F127) hard-gel modulus is recovered at 4 to 5% nanocrystal loading, yet the composite gel is much more deformable (and tougher) in the presence of the CNC network. Our temperature sweep experiments show that the CNC addition up to 3% does not change the rapid thermal gelation of the F127 solutions; therefore, these composites are suitable for smart drug delivery systems. On the other hand, at higher CNC concentrations, abrupt viscosity transition is not observed, rather the composite gels smoothly thicken with temperature in contrast to thermal thinning of the aqueous neat CNC. Thus, they can be used as smartly adaptive biolubricants and bioviscostatic materials.

Packaging and degradability properties of polyvinyl alcohol/gelatin nanocomposite films filled water hyacinth cellulose nanocrystals

Cellulose nanocrystals isolated from water hyacinth fiber (WHF) have been studied as a reinforcement for polyvinyl alcohol (PVA)-gelatin nanocomposite. Central composite design was used to study and optimize effects of the PVA, gelatin and cellulose nanocrystal (CNC) concentration on tensile strength and elongation of formed films. The results of this study showed that WHF CNC had a diameter range of 20–50 nm produced films reaching 13.8 MPa tensile strength. Thermal stability of the films was improved from 380 °C to 385 °C in addition of CNCs and maximum storage modulus of 3 GPa were observed when 5 wt% CNC was incorporated. However, water absorption, water vapour permeability (WVP) and moisture uptake of the films decreased in addition of CNC to the PVA-gelatin blends. Moisture uptake decreased from 22.50% to 19.05% while the least WVP when 10 wt% CNC added was 1.64 × 10–6 g/(m•h•Pa). These results show possibility for industrial application of WHF CNC and PVA-gelatin blends in biodegradable films for on-the-go food wrappers.

Cell-Laden Nanocellulose/Chitosan-Based Bioinks for 3D Bioprinting and Enhanced Osteogenic Cell Differentiation.

3D bioprinting has recently emerged as a very useful tool in tissue engineering and regenerative medicine. However, developing suitable bioinks to fabricate specific tissue constructs remains a challenging task. Herein, we report on a nanocellulose/chitosan-based bioink, which is compatible with a 3D extrusion-based bioprinting technology, to design and engineer constructs for bone tissue engineering and regeneration applications. Bioinks were prepared using thermogelling chitosan, glycerophosphate, hydroxyethyl cellulose, and cellulose nanocrystals (CNCs). Formulations were optimized by varying the concentrations of glycerophosphate (80-300 mM), hydroxyethyl cellulose (0-0.5 mg/mL), and CNCs (0-2% w/v) to promote fast gelation kinetics (<7 s) at 37 °C and retain the shape integrity of constructs post 3D bioprinting. We investigated the effect of CNCs and pre-osteoblast cells (MC3T3-E1) on the rheological properties of bioinks, bioink printability, and mechanical properties of bioprinted scaffolds. We demonstrate that the addition of CNCs and cells (5 million cells/mL) significantly improved the viscosity of bioinks and the mechanical properties of chitosan scaffolds post-fabrication. The bioinks were biocompatible and printable at an optimized range of printing pressures (12-20 kPa) that did not compromise cell viability. The presence of CNCs promoted greater osteogenesis of MC3T3-E1 cells in chitosan scaffolds as shown by the upregulation of alkaline phosphatase activity, higher calcium mineralization, and extracellular matrix formation. The versatility of this CNCs-incorporated chitosan hydrogel makes it attractive as a bioink for 3D bioprinting to engineer scaffolds for bone tissue engineering and other therapeutic applications.

Cooperative Effects of Cellulose Nanocrystals and Sepiolite When Combined on Ionic Liquid Plasticised Chitosan Materials.

Cellulose nanocrystals (CNCs) and/or sepiolite (SPT) were thermomechanically mixed with un-plasticised chitosan and chitosan/carboxymethyl cellulose (CMC) blends plasticised with 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]). Examination of the morphology of these materials indicates that SPT aggregates were reduced when CNCs or [C2mim][OAc] were present. Inclusion of CNCs and/or SPT had a greater effect on material properties when the matrices were un-plasticised. Addition of SPT or CNCs altered the crystalline structure of the un-plasticised chitosan matrix. Moreover, a combination of SPT and CNCs was more effective at suppressing re-crystallisation. Nonetheless, the mechanical properties and surface hydrophobicity were more related to CNC/SPT–biopolymer interactions. The un-plasticised bionanocomposites generally showed increased relaxation temperatures, enhanced tensile strength, and reduced surface wettability. For the [C2mim][OAc] plasticised matrices, the ionic liquid (IL) dominates the interactions with the biopolymers such that the effect of the nanofillers is diminished. However, for the [C2mim][OAc] plasticised chitosan/CMC matrix, CNCs and SPT acted synergistically suppressing re-crystallisation but resulting in increased tensile strength.

Comparison between cellulose nanocrystal and microfibrillated cellulose as reinforcement of poly(vinyl acetate) composites obtained by either in situ emulsion polymerization or a simple mixing technique

Nanocellulose is abundant, renewable, biocompatible, and a good candidate as reinforcement agent in nanocomposites; however, its hydrophilicity leads to poor dispersion in hydrophobic polymers. Recently, both in situ polymerization and cellulose surface modification have been used to improve dispersion, but emulsion polymerization is rarely adopted, and when it is, the reinforcement agent is usually cellulose nanocrystal (CNC), with gain in mechanical properties being the main focus of the research. Therefore, this work aims to explore the influence of adding either CNC or microfibrillated cellulose (MFC), both without surface modification, on the mechanical resistance, thermal degradation, and water vapor permeability of poly(vinyl acetate) composites obtained by either in situ emulsion polymerization or mixing. The results showed that despite having similar impacts on thermal and barrier properties, MFC and CNC affect the mechanical properties of their composites differently. Both cause decrease of the thermal degradation rate and do not have a significant impact on water vapor permeability. However, the addition of CNC during synthesis increased composite mechanical resistance significantly while the addition of MFC did not show improvement. Mechanical resistance is also strongly dependent on the procedure used to produce the composites.

Preparation and characterization of enzymatically cross-linked gelatin/cellulose nanocrystal composite hydrogels.

Gelatin is an attractive hydrogel material because of its excellent biocompatibility and non-cytotoxicity, but poor mechanical properties of gelatin-based hydrogels become a big obstacle that limits their wide-spread application. To solve it, in this work, gelatin/cellulose nanocrystal composite hydrogels (Gel-TG-CNCs) were prepared using microbial transglutaminase (mTG) as the crosslinking catalyst and cellulose nanocrystals (CNCs) as reinforcements. The physicochemical properties of the composite hydrogels were investigated by thermogravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The dynamic rheological measurement and uniaxial compression test were performed to study the effects of mTG and CNC contents on the storage modulus and breaking strength of the as-prepared Gel-TG-CNCs. Results showed that the addition of CNCs and mTG could significantly increase the storage modulus and breaking strength of gelatin-based hydrogels, especially when added simultaneously. The breaking strength of Gel-TG-CNCs (2%) at 25 °C can reach 1000 g which is 30 times greater than pure gelatin hydrogels. The biocompatibility of the composite hydrogels was also investigated by the MTT method with Hela cells, and the results demonstrated that the composite hydrogels maintained excellent biocompatibility. With a combination of good biocompatibility and mechanical properties, the as-prepared Gel-TG-CNCs showed potential application value in the biomedical field.

The effects of reinforced cellulose nanocrystals from sugarcane bagasse fiber on the hardness of glass ionomer cements

Background: Advances in nanotechnology research make the use of cellulose nanocrystals (CNCs) attractive for improving the mechanical properties of glass ionomer cement (GIC). Sugarcane bagasse (Saccharum officinarum L.) is a CNCs source with a high CNC content (72.5%). Objective: This study aimed to determine the effect of the addition of sugarcane bagasse CNCs on the mechanical properties of GIC. Methods: In total, 42 GIC (Fuji IX, GC, Japan) samples were divided into six groups, with various concentrations of CNCs, added to the samples. After 24 h immersion in distilled water at 37°C, the samples were analyzed using the Vickers hardness test. The samples were also characterized by transmission electron microscopy (TEM). For statistical analysis, a one-way analysis of variance, followed by Tukey's post hoc test, was applied. A value of P