Cellulose Filaments Research Articles

Interlayer bonding performance of 3D printed engineered cementitious composites (ECC): Rheological regulation and fiber hybridization

The weak interlayer adhesion caused by the layer-by-layer 3D printing (3DP) process and the incorporation of organic fiber in Engineered Cementitious Composites (ECC), detrimentally impacts the integrity of 3DP-ECC structures, particularly for large-scale structures requiring extended open time. To optimize the printing quality and extent the operation time, cellulose filaments (CF) were employed as nano-reinforcement, viscosity modifier and water retainer, and were hybridized with polyethylene fiber (PE) and steel fiber (ST). The highest bonding strength was raised up to 3.51 MPa. The time-dependent escalation of rheological parameters was mitigated, reducing interlayer porosity to 0.56 % and limiting the reduction in bonding strength to 12.01 % within 60 min open time. The compressive anisotropy was almost eliminated, verifying the potential of CF in modifying interlayer adhesion. A linear correlation between rheological behavior and interlayer bonding performance was established, and a 0.508 Pa s/min plastic viscosity growth rate was suggested to avoid cold joint and ensure printing quality.

“Reinforced concrete” design of robust mineralized cellulose composite with multilayered structure for efficient CO2 capture and passive radiative cooling ability

The construction industry promotes the economic development of the country by addressing society's housing needs. However, the industry's energy consumption and carbon dioxide (CO2) emissions are the primary contributors to global warming. Traditional building materials are no longer capable of meeting the requirements of sustainable development, while natural cellulose can be used as a new type of carbon capture construction material. Inspired by the “reinforced concrete” methodology, a mineralized cellulose composite (ML-CCM) was fabricated through a strategy of vacuum filling and in-situ mineralization, resulting in a composite with a multi-level structure (a natural microporous 3D scaffold loofah as “rebar” and cellulose filler as “cement” are staggered in the composite). The resultant ML-CCM1 exhibited a significantly high flexural strain (approximately 215.9 % of that of cellulose composite without loofah) because of the 3D scaffold loofah acting as a “rebar”. Furthermore, the composite possesses flame retardancy, superior thermal insulation at 90 °C, and passive radiative cooling performance due to the micro-nano ZnO particle in the “cement”. Moreover, the multi-level structure, consisting of pores and micro-nano particles, enables it to effectively adsorb CO2 and environment tobacco smoke. As a result, lifecycle assessments underscore the composite's low Global Warming Potential. Therefore, this work reports a promising 3D bio-based composite with CO2 capture for energy conservation and carbon reduction in the construction industry.

Multi-objective optimization of micro crystalline cellulose and montmorillonite filled poly lactic acid bio–composite and its characterizations

In this research study, the synthesis of poly lactic acid (PLA) based bio composite material factors contributions were investigated through the Taguchi-based grey relational analysis (GRA) technique. Effects of micro crystalline cellulose (MCC) and montmorillonite (MTT) nano clay filler, sorbitol (S) plasticizer, and temperature (T) operating factor on the PLA matrix through melt-mixing preparation method. The tensile strength (TS), Young modulus (YM), flexural strength (FS), flexural modulus (FM), hardness, impact strength (IS), water absorption (WA), and density properties of bio composite material were investigated for each experimental setup (orthogonal array, L16). Additionally, neat PLA and optimal sample structural, thermal, and morphological properties were examined through Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (X-RD), thermal gravimetry analysis/differential thermal gravimetry (TGA/DTG), and DSC and SEM analyses. The obtained result for optimal mechanical and physical properties of MCC/MTT/S/PLA bio composite was MCC at level 3 (6%), MTT at level 4 (9%), S at level 2 (10%), and T at level 4 (175 °C). Analysis of variance (ANOVA) shows that MTT has the greatest significant effect on mechanical and physical properties of MCC/MTT/S/PLA bio composite followed by MCC, T, and S. The confirmation test indicates that the improvement of weighted grey relational grade (GRG) from 0.7896 to 0.846 and the FTIR, XRD, thermal gravimetry/differential scanning calorimetry (TG/DSC), and scanning electron microscopy (SEM) results indicates that the good interaction between PLA and fillers, improvement of thermal and morphological properties of optimal (6MCC/9MTT/10S/175 °C) bio composite samples. Therefore, the multi-response characteristics of MCC/MTT/S/PLA bio composite can be highly improved by this technique.

3D printing hybrid-fiber reinforced engineered cementitious composites (3DP-HECC): Feasibility in long-open-time applications

Hybridization of multi-scale and multi-functional fibers to generate Hybrid-fiber Engineered Cementitious Composites (HECC) offers a promising approach for enhancing ECC in 3D printing (3DP), addressing limitations such as restricted build-up height and operation time. This study strategically combined polyethylene (PE) fiber (1.0 %), steel fiber (0.5 %) and cellulose filaments (CF) at various dosages (0–0.25 %) to investigate the evolution of rheological behavior over different time intervals (0–60 min with 15 min intervals) and optimize the printability of 3DP-HECC with long-open-time. Incorporating of CF or steel fiber enhanced static yield stress, dynamic yield stress and plastic viscosity, particularly benefiting buildability with steel fiber inclusion. Moreover, CF integration effectively moderated the growth rates of static yield stress and dynamic yield stress while maintaining thixotropic index, mitigating extrusion defects and extending operation time to 60 min for structure-level printing. Conversely, steel fiber exhibited contrasting behavior. By integrating the evolution of time-dependent rheological parameters and practical printing observations, an optimum CF dosage of 0.20 % was identified for high-quality 3DP with superior build-up layers. Finally, a fiber hybridization strategy was suggested to optimize the printability of 3DP-HECC, providing theoretical guidance for implementing high-quality applications with extended operation time.

Elastomeric Compositions of Ethylene-Norbornene Copolymer Containing Biofillers Based on Coffee and Tea Waste.

The development of eco-friendly elastomeric materials has become an important issue in recent years. In this work, thermoplastic elastomer samples of an ethylene-norbornene copolymer (EN) with coffee and tea biofillers mixed with typical fillers such as montmorillonite (MMT), silica (SiO2), and cellulose were investigated. The aim of this research was to determine the effect of fillers on the properties of the materials and to assess their degradability after two ultraviolet (UV) aging cycles (200, 400 h). The scientific novelty of this work is the assessment of the anti-aging effect of simultaneous biofillers-stabilizers based on coffee and tea waste. The surfaces of the obtained polymer compositions were examined using infrared spectroscopy (FTIR-ATR). Contact angles were determined, and surface energy was calculated. The mechanical properties were tested, and the influence of plant fillers and aging on the color change in the materials was analyzed. The combination of coffee with silica, MMT, and cellulose fillers limited the migration of fatty acids and other compounds from the biofiller to the EN surface (FTIR analysis). Based on the aging coefficients K, it was shown that all coffee- and tea-based fillers stabilized the polymer compositions during UV aging (400 h). The results allowed the authors to determine the importance and impact of waste plant fillers on the degradability of the synthetic EN.

Cellulose reinforcement of plant-based protein hydrogels: Effects of cellulose nanofibers and nanocrystals on physicochemical properties

This study explored the impact of cellulose-derived fillers, cellulose nanofibers (CNFs) and cellulose nanocrystals (CNCs), on the microstructure and texture of potato protein hydrogels (20 wt% protein). Particle size analysis, surface charge analysis, and molecular docking simulations suggested that the cellulose nanofibers and nanocrystals acted as inactive fillers within the potato protein matrix. Texture profile analysis showed that incorporation of small amounts of CNFs (<1%) increased the gel strength (by up to 69%), but the addition of larger amounts decreased it, which was attributed to disruption of the protein network by aggregated nanofibers at higher concentrations. The incorporation of CNCs had a much smaller effect on the gel strength of the potato protein hydrogels, only increasing it by up to 15% at 2% CNC. Shearing the cellulose-reinforced hydrogels in a shear rheometer had little impact on their gel strength at lower filler concentrations (<2 wt%) but increased it at higher concentrations. Microscopy analysis showed that the cellulose fibers could be aligned at sufficiently high shearing rates, leading to a fibrous microstructure. This study provides valuable insights into the optimization of the properties of cellulose fillers for application in plant protein hydrogels. In particular, it suggests that they may be utilized in plant-based meat analogs to enhance their textural attributes and optimize their appearance.

Cellulose/castor oil‐based polyurethane film composite for aqueous Cd and Pb adsorption: Evaluation using laser‐induced breakdown spectroscopy

AbstractCastor oil‐based polyurethane has been researched for its utility in heavy metal adsorption. To improve the adsorptive performance, the polymer can be incorporated with cellulose—a renewable and widely available biopolymer. The aim of this research was to synthesize a film composite prepared from castor oil‐based polyurethane and cellulose for adsorptive removal of aqueous Cd and Pb. One‐shoot synthesis method was employed by mixing cellulose filler with castor oil and toluene diisocyanate (TDI). Characterization was carried out by FT‐IR, SEM, TGA, DSC, and contact angle analyses. Batch adsorption was carried out for the Cd and Pb with variations in contact time and initial pH, before analyzed for the adsorptive performance using 1064 nm Nd:YAG laser spectroscopy. The resulted adsorbents had improved thermal stability, and lower hydrophobicity. Adsorption of Pb and Cd increased 2 and 35 times after the addition of 0.1 g cellulose, respectively. Batch adsorption test revealed that the optimum conditions are 120‐min contact time and pH of 9 and 7 (for Cd and Pb, respectively). In conclusion, incorporation of cellulose could modify the characteristics of castor oil‐based polyurethane film and improve the adsorption of Cd and Pb.

Recyclability and self-healing capability in reinforced ionic elastomers

This study presents a comparative analysis of different sustainable alternatives for producing reinforced ionic elastomers that are not just mechanically robust but also excellent in recyclability and self-healing, marking a significant advancement in sustainable materials science. Ionically crosslinked carboxylated nitrile rubber (XNBR) was combined with conventional (carbon black and silica) and sustainable (cellulose and ground tire rubber) fillers. The sustainable fillers not only enhanced the mechanical performance (reinforcing character) but also maintained high healing efficiencies (>80 %). Notably, the incorporation of just 10 phr of waste-based ground tire rubber (GTR) produced by water jet grinding (WJ-GTR) resulted in a material capable of complete repair and recycling (100 % efficiency) after temperature-driven protocols, with mechanical properties and a reinforcement index comparable to those of conventional fillers such as silica. This achievement represents a major breakthrough in the field of sustainable composites, as it offers a unique blend of robust mechanical properties and environmental sustainability.

Sustainable 3D-printed cellulose-based biocomposites and bio-nano-composites: Analysis of dielectric performances

The development of cellulose-reinforced biomaterials appears to be an attractive approach for the production of sustainable materials with good mechanical properties. Although 3D printing of cellulose-reinforced biomaterials has become popular, there is very little feedback regarding their use in electrical insulation applications. This study aims to propose bio-nano-composites containing polylactic acid (PLA), microcrystalline (MCC) and nanocrystalline (NCC) cellulose by fused filament fabrication (FFF) for electrical insulation applications. The influence of the 3D printing process, cellulose content and filler size on dielectric properties was investigated. The addition of cellulosic fillers, and considering their high polarity, increased the dielectric constant (ε'), dielectric loss (ε''), as well as the AC electrical conductivity (σAC) of the composites. Cellulosic fillers also increased the crystallization rate of the materials. At equivalent content, the highest polarization potential were observed for NCC-based composites and were attributed to the nanofiller's better dispersion and available specific surface area. Finally, the 3D printing process affects all the measured properties, due to a combined effect (lower crystalline content and voids presence). The porosity rate was measured at 2.5 % for the neat PLA and increased progressively from 3.1 % to 5.8 % for the cellulose-based composites. These findings showed the benefits provided by the FFF technology in the production of cellulose-based biocomposites with good electrical insulation properties, while noting some needed feedback on the thermomechanical properties of such materials.

Layer-by-layer coated cellulose reduces the fire risk of polyurethane foam biocomposites

Cellulose implementation as filler in polyurethane foams (PUF) often leads to an increased the fire risk associated to the prepared biocomposite. To address this problem, this paper presents a novel approach where the cellulose filler is coated by a nanostructured layer-by-layer (LbL) assembly with flame retardant characteristics before its addition to the biocomposite. During PUF production, the presence of cellulose led to a reduced cell size distribution with improved thermal insulation properties. By forced combustion tests, the use of neat cellulose produced a detrimental effect by increasing the PUF heat release rates (up to +21 %). Conversely, the coated cellulose simultaneously decreased the peak of heat release rate (-22 %) and the total smoke release (-32 %) if compared with the reference PUF. The proposed approach represents a viable strategy for the production of PUF biocomposites where sustainability and fire protection are optimized.

Melt compounding of spray-dried cellulose nanofibrils/polypropylene and their application in 3D printing

Micro- and nano-scale cellulosic fillers exhibit excellent dispersion and distribution within a thermoplastic matrix during the process of melt compounding or injection molding. In this study, spray-dried cellulose nanofiber (SDCNF) powders were manufactured using a pilot-scale rotating disk atomizer spray dryer. Bleached Kraft pulp (BKP), unbleached Kraft pulp (UKP), and old corrugated cardboard pulp (OCC) fibrillated at a fines level of 90% were used as feedstock materials for spray-drying. BKP-, UKP-, and OCC- SDCNFs were compounded with polypropylene using a twin screw co-rotating extruder. Maleic anhydride grafted polypropylene (MAPP) was used as a coupling agent in the composite formulations. The tensile, flexural, and impact properties of SDCNF-filled PP composites increased at 10 wt% SDCNF loading. The presence of SDCNFs in the PP matrix resulted in faster crystallization and a 12% reduction in the degree of crystallinity of the neat PP. The coefficient of thermal expansion (CTE) of neat PP was reduced by up to 31% attributable to the presence of the SDCNFs. Application of the SDCNF-reinforced PP composites in 3D printing reduced the shrinkage rate of the printed neat PP by 39%, and the printability of the PP was significantly improved with the addition of the SDCNFs.

Fully biobased thermal insulating aerogels with superior fire-retardant and mechanical properties

Biomass-based aerogels offer a promising potential as alternatives to plastic-based foams for thermal insulation applications. However, their inherent flammability has hindered their practical usage. In this work, we addressed this issue by employing a layer-by-layer assembly technique to deposit two oppositely charged biobased materials, namely phytic acid and chitosan, onto a fully biobased aerogel system. These aerogels were fabricated using cellulose filaments and chitosan and cross-linked with citric acid, resulting in a mechanically robust 3D structure. The synergistic effects of phytic acid and chitosan in the layer-by-layer deposited aerogels significantly enhanced their fire resistance and mechanical strength. The developed aerogel with six bilayer depositions (LBL6), showed an outstanding peak heat release rate (pHRR) of 6.0 kW.m−2, and total heat release (THR) of 0.4 MJ.m−2, substantially lower than the previously developed cellulose-based aerogels and foams. LBL6 also demonstrated immediate self-extinguishing behaviour, boasting an impressive limiting oxygen index (LOI) value of 63 %, which is the highest reported for a biobased aerogel. Furthermore, the developed aerogels exhibited a superior Young’s modulus of up to 4.5 MPa, surpassing previously developed flame-retardant aerogels. Additionally, they excelled in thermal insulation properties, with a thermal conductivity of less than 38.2 mW·m−1·K−1, placing them in the same range as, or even lower than, commercially available thermal insulators. Given the simplicity of the aerogel development process and the well-known advantages of a completely biobased system, our developed aerogels present a sustainable and environmentally friendly alternative to current commercial thermal insulators that are derived from petroleum-based materials.

Isolation and characterization of banyan tree root filler for polymer composites in light-weight applications

The applicability of bio fillers as reinforcement with polymers is promoted by economic and ecological concerns. Nowadays, a large range of reinforcements are employed for this purpose, including cellulosic fillers and natural fibres owing to the favorable mechanical behavior, cheap price, negligible tool wear, low density, and eco-friendliness etc. The motive of this investigation is to explore the possibilities of utilizing plant sources as reinforcing filler in polymeric matrices. In this study particulate fillers were obtained from banyan tree’s aerial roots and were subjected to various characterization such as physiochemical evaluation, Fourier Transform Infrared Spectroscopy (FTIR), x-ray diffraction (XRD), thermal analysis (TGA), and Scanning Electron Microscopy (SEM). From the physiochemical analysis it was found that the banyan tree aerial root filler (BTAR) contained 40.13% of Cellulose, 15.22% of Hemicellulose, 15.31% of Lignin and 6.86% of Pectin. The density of the BTAR filler was found to be 0.27 gm cc−1 whereas the average particle size was 136.3 μm. The maximum inflection temperature referred to the maximum degradation of the BTAR filler was 295.7 °C. The SEM analysis exposed the rough surface of filler, with micro-structured strands and pores. The rough surface and the pores could help in better bond ability of the matrix and reinforcement when combined. Given the features of the examined BTAR filler, it is suggested as potential reinforcing filler for polymer composites to strengthen material properties for different light weight applications.

Fabrication of smart vapor barrier membranes from polyhydroxyalkanoate and cellulose filaments for building envelope applications

Fabrication of smart vapor barrier membranes from polyhydroxyalkanoate and cellulose filaments for building envelope applications

Evaluation of binders in twin-screw wet granulation – Optimization of tabletability

The influence of hydroxypropyl cellulose type (HPC-SSL SFP, HPC-SSL), concentration (2 %, 3.5 %, 5 %) and filler (lactose, calcium hydrogen phosphate (DCP)/microcrystalline cellulose (MCC)) on twin-screw wet granulation and subsequent tableting was studied. The aim was to identify the formulation of the highest tabletability which still fulfills the requirements of the disintegration. Lactose combined with 5 % binder enabled a higher tabletability and a faster disintegration than DCP/MCC. It was found that tabletability of lactose formulations can be increased by higher binder concentration and higher compression pressure while tabletability of DCP/MCC formulations can be only increased by higher compression pressure. It was observed that batches containing DCP/MCC failed the disintegration test, if the highest binder concentration and the highest compression pressure were used. To ensure a fast disintegration, the compression pressure or at least the binder concentration had to be low. Changing the disintegrant and its localization improved the DCP/MCC formulation, resulting in faster disintegration than lactose tablets. However, it also resulted in a lower tabletability. In this study best tablets were achieved with 3.5 % or 5 % binder and lactose as filler. These tablets presented the highest tabletability but still disintegrated in less than 500 s.

Physico-electrical properties of starch-based bioplastic enhanced with acid-treated cellulose and graphene oxide fillers

Biopolymer composites represent an emerging alternative to petroleum-derived polymers for applications in electronic devices. Cellulose from Luffa cylindrical was treated with acid, and graphene oxide was produced from waste battery rod graphite. The two products were characterized using FTIR, SEM, TGA and XRD. After that, starch-based bioplastic films with varying amounts of acid-treated cellulose (ALC-cellulose) and graphene oxide (GO) as fillers were prepared, and the physical and electrical properties were determined. XRD data revealed a crystallinity of 62% for the ALC-cellulose and 52% for the cellulose precursor. GO had a d-spacing of 0.76 nm compared to 0.29 nm for battery-sourced graphite. TEM micrograph analyses revealed an average fibre diameter of 44.7 nm for acid-treated cellulose and 99.7 nm for cellulose. The density, thickness, opacity, and tensile strength of the bioplastic films increased from 1.31 to 1.44 g/cm3, 0.21–0.48 mm, 14.78–38.64, and 0.98–1.42 MPa, respectively, while the moisture content, swelling ability, and porosity reduced, with an increase in percentage composition of the filler materials. The dielectric constant and conductivity increased from 50.3 to 6965.2 and 0.0036–0.0147 S/m with an increase in percentage composition of the filler materials except for Filmcr4, which showed a drop in dielectric constant (3033.73) and conductivity (0.0074 S/m). Overall, this study has demonstrated that bioplastic filler materials can be sourced from waste materials and that these fillers improved the starch-based bioplastic film's physical and electrical properties.

Effects of cellulose micro and nanocrystals on the mechanical, thermal, morphological, and structural properties of rigid polyurethanes

Effects of adding microcrystalline cellulose (MCC) and cellulose nanocrystals (CNC) were evaluated relative to the mechanical, thermal, morphological, and structural properties of rigid polyurethanes (rPUs). The composites were prepared with the blending of polyols/isocyanates and the cellulosic fillers at 0.25%, 0.5%, and 1% loadings. Scanning electron microscopic images showed that the samples had micro-scaled porosity, with cell sizes ranging from 250 to 800 nm. The fillers improved the mechanical strengths and modulus of neat rPUs due to the presence of the nano-sized cells in rPUs matrix. The addition of both fillers generally did not provide a positive effect on the thermal properties, and the weight loss generally increased while the loading rate of the fillers was increased from 0.25% to 1%. The samples had two small crystalline peaks at 18° and 19° according to the X-ray diffraction analysis. From the results, it can be said that the presence of both fillers generally improved all properties of the neat rPUs, and the effects of CNC on the properties were higher than MCC due to both lower particle size and the higher crystallinity of CNC.

Aesthetic Cellulose Filaments with Water-Triggered Switchable Internal Stress and Customizable Polarized Iridescence Toward Green Fashion Innovation.

Healthy, convenient, and aesthetic hair dyeing and styling are essential to fashion trends and personal-social interactions. Herein, we fabricate green, scalable, and aesthetic regenerated cellulose filaments (ACFs) with customizable iridescent colors, outstanding mechanical properties, and water-triggered moldability for convenient and fashionable artificial hairdressing. The fabrication of ACFs involves cellulose dissolution, cross-linking, wet-spinning, and nanostructured orientation. Notably, the cross-linking strategy endows the ACFs with significantly weakened internal stress, confirmed by monitoring the offset of the C-O-C group in the cellulose molecular chain with Raman imaging, which ensures a tailorable orientation of the nanostructure during wet stretching and tunable iridescent polarization colors. Interestingly, ACFs can be tailored for three-dimensional shaping through a facile water-triggered adjustable internal stress: temporary shaping with low-level internal stress in the wet state and permanent shaping with high-level internal stress in the dry state. The health, convenience, and green aesthetic filaments show great potential in personal wearables.

Reversible Surface Engineering of Cellulose Elementary Fibrils: From Ultralong Nanocelluloses to Advanced Cellulosic Materials.

Cellulose nanofibrils (CNFs) are supramolecular assemblies of cellulose chains that provide outstanding mechanical support and structural functions for cellulosic organisms. However, traditional chemical pretreatments and mechanical defibrillation of natural cellulose produce irreversible surface functionalization and adverse effects of morphology of the CNFs, respectively, which limit the utilization of CNFs in nanoassembly and surface functionalization. Herein, this work presents a facile and energetically efficient surface engineering strategy to completely exfoliate cellulose elementary fibrils from various bioresources, which provides CNFs with ultrahigh aspect ratios (≈1400) and reversible surface. During the mild process of swelling and esterification, the crystallinity and the morphology of the elementary fibrils are retained, resulting in high yields (98%) with low energy consumption (12.4kJ g-1). In particular, on the CNF surface, the surface hydroxyl groups are restored by removal of the carboxyl moieties via saponification, which offers a significant opportunity for reconstitution of stronger hydrogen bonding interfaces. Therefore, the resultant CNFs can be used as sustainable building blocks for construction of multidimensional advanced cellulosic materials, e.g., 1D filaments, 2D films, and 3D aerogels. The proposed surface engineering strategy provides a new platform for fully utilizing the characteristics of the cellulose elementary fibrils in the development of high-performance cellulosic materials.

Cellulose Nanostructures as Tunable Substrates for Nanocellulose-Metal Hybrid Flexible Composites.

Nanocomposite represents the backbone of many industrial fabrication applications and exerts a substantial social impact. Among these composites, metal nanostructures are often employed as the active constituents, thanks to their various chemical and physical properties, which offer the ability to tune the application scenarios in thermal management, energy storage, and biostable materials, respectively. Nanocellulose, as an emerging polymer substrate, possesses unique properties of abundance, mechanical flexibility, environmental friendliness, and biocompatibility. Based on the combination of flexible nanocellulose with specific metal fillers, the essential parameters involving mechanical strength, flexibility, anisotropic thermal resistance, and conductivity can be enhanced. Nowadays, the approach has found extensive applications in thermal management, energy storage, biostable electronic materials, and piezoelectric devices. Therefore, it is essential to thoroughly correlate cellulose nanocomposites' properties with different metallic fillers. This review summarizes the extraction of nanocellulose and preparation of metal modified cellulose nanocomposites, including their wide and particular applications in modern advanced devices. Moreover, we also discuss the challenges in the synthesis, the emerging designs, and unique structures, promising directions for future research. We wish this review can give a valuable overview of the unique combination and inspire the research directions of the multifunctional nanocomposites using proper cellulose and metallic fillers.