Cellulose Filaments Research Articles

Effect of Soy Waste/Cellulose on Mechanical, Water Sorption, and Biodegradation Properties of Thermoplastic Starch Composites

AbstractThermoplastic starch (TPS)/soy pulp (soy waste) composites (TSS) with varying compositions are successfully prepared in an internal mixer followed by compression molding. The mechanical, water absorption, and biodegradable properties of the developed composites are studied and compared with virgin TPS and cellulose reinforced TPS composites (TSC). Optimum tensile and flexural strength is observed for TSS and TSC composites with 10 wt.% soy waste and cellulose. Fourier Transform Infrared Spectroscopy (FT‐IR) and Scanning Electron Microscope (SEM) analyses indicated the interaction occurred between soy pulp/cellulose and TPS. Water absorptivity is found to increase from 6.2% to as high as 42.3% with the addition of 0 to 25 wt.% cellulose filler to the TPS matrix. Moreover, the soil burial degradation study shows higher degradability of the composites with a higher amount of soy pulp/cellulose. The developed composites show moderate mechanical properties with a hydrophobic and biodegradable nature. Therefore, there is a great possibility for these biocomposites to be utilized in applications such as disposable items, packaging materials, office cuboids, and transport sectors.

Effect of the addition of cellulose filaments on the relaxation behavior of thermoplastics

In this work, the effect of cellulose filaments (CFs) dispersion on the relaxation behavior of thermoplastics matrices was studied. The dispersion state of polystyrene/CF composites produced by two different processing methods, leading to two different dispersion qualities, was assessed using scanning electron microscopy (SEM), transmission electron microscopy, and small amplitude oscillatory shear (SAOS). Instead of the generally used plateau value of G′, the melt yield stress of the modified Carreau–Yasuda model was used to find an accurate value of the percolation threshold concentration. It was concluded that in this case, the process involving a solution mixing step led to a better dispersion than the process involving only melt mixing. Then, using the weighted relaxation spectra calculated using the Honerkamp and Weese method on SAOS results, it was shown that the better the dispersion, the more delayed the relaxation process of the polymer matrix. Finally, by studying the relaxation spectra as well as the melt yield stress of polypropylene/CF composites, it was possible to understand the evolution of their morphology upon CF concentration. It was shown that below 5 wt. %, a well dispersed network of CF was obtained, whereas from 5 to 15 wt. % CFs were agglomerating, then leading to a network of agglomerated fibers for concentrations above 15 wt. %. Those assessments done using SAOS results were confirmed by SEM.

Evaluation of Algae-Based Fertilizers Produced from Revolving Algal Biofilms on Kentucky Bluegrass

The revolving algal biofilm (RAB) system is a wastewater treatment method that is effective at removing nutrients from wastewater, and as a result produces algae that could be used as a sustainable fertilizer source. A two-year greenhouse study was conducted to investigate if algae-based fertilizers produced from the RAB wastewater treatment system could be used as an effective and sustainable turfgrass fertilizer. Fertilizer treatments included pure algae (PA), algae + cellulosic filler (Blended), Milorganite, urea, and a nontreated control. Overall, in terms of percent green cover (PGC), Blended and PA performed similar to Milorganite and outperformed urea and the nontreated control. At the conclusion of the study, Blended was the only treatment to have an increased PGC relative to urea, which was a 29% increase. On average throughout the duration of the study, Blended and PA resulted in similar dark green color index (DGCI) relative to Milorganite and urea, and outperformed the nontreated control. Blended, PA, and Milorganite resulted in 50% and 111% greater total root length compared to urea and the nontreated control, respectively. Furthermore, Blended and Milorganite resulted in 107% and 136% greater root surface area and root volume, respectively, compared to urea and the nontreated control. Pure algae resulted in 58% greater root surface area relative to urea and the nontreated control. Blended and Milorganite increased the longest root by 22% compared to urea. Additionally, Blended and Milorganite resulted in 114% and 110% greater root and shoot biomass relative to the nontreated control, respectively. Blended and PA had a similar longest shoot length to Milorganite and urea. Overall, Blended and PA performed similar or better compared to Milorganite and urea in terms of turfgrass shoot growth, cover, color, and rooting. Thus, algae-based fertilizers (PA and Blended) produced from the RAB system should be considered an effective, sustainable turfgrass fertilizer.

Polyurethane Composite Foams Synthesized Using Bio-Polyols and Cellulose Filler.

Rigid polyurethane foams were obtained using two types of renewable raw materials: bio-polyols and a cellulose filler (ARBOCEL® P 4000 X, JRS Rettenmaier, Rosenberg, Germany). A polyurethane system containing 40 wt.% of rapeseed oil-based polyols was modified with the cellulose filler in amounts of 1, 2, and 3 php (per hundred polyols). The cellulose was incorporated into the polyol premix as filler dispersion in a petrochemical polyol made using calenders. The cellulose filler was examined in terms of the degree of crystallinity using the powder X-ray diffraction PXRD -and the presence of bonds by means of the fourier transform infrared spectroscopy FT-IR. It was found that the addition of the cellulose filler increased the number of cells in the foams in both cross-sections—parallel and perpendicular to the direction of the foam growth—while reducing the sizes of those cells. Additionally, the foams had closed cell contents of more than 90% and initial thermal conductivity coefficients of 24.8 mW/m∙K. The insulation materials were dimensionally stable, especially at temperatures close to 0 °C, which qualifies them for use as insulation at low temperatures.

Chemical and physical interactions of regenerated cellulose yarns and isocyanate-based matrix systems

In the development of structural composites based on regenerated cellulose filaments, the physical and chemical interactions at the fibre-matrix interphase need to be fully understood. In the present study, continuous yarns and filaments of viscose (rayon) were treated with either polymeric diphenylmethane diisocyanate (pMDI) or a pMDI-based hardener for polyurethane resins. The effect of isocyanate treatment on mechanical yarn properties was evaluated in tensile tests. A significant decrease in tensile modulus, tensile force and elongation at break was found for treated samples. As revealed by size exclusion chromatography, isocyanate treatment resulted in a significantly reduced molecular weight of cellulose, presumably owing to hydrolytic cleavage caused by hydrochloric acid occurring as an impurity in pMDI. Yarn twist, fibre moisture content and, most significantly, the chemical composition of the isocyanate matrix were identified as critical process parameters strongly affecting the extent of reduction in mechanical performance. To cope with the problem of degradative reactions an additional step using calcium carbonate to trap hydrogen ions is proposed.

Elaboration and properties of nanofibrillated cellulose composites with polypyrrole nanotubes or their carbonized analogs

Flexible electrically conductive composites based on renewable resources have attracted a growing interest for the development of high performance sustainable electronic and energy storage devices. In this study, electrically conductive flexible composite films based on nanofibrillated cellulose (NFC) and conductive nanotubular fillers were elaborated using environmentally friendly approach. Three conductive fillers were tested, specifically polypyrrole nanotubes (PPy-NT), carbonized polypyrrole nanotubes (C-PPy-NT) and commercially available multi-walled carbon nanotubes (MWCNT) for comparison. The prepared films were assessed for potential applications as electrodes for energy storage devices or protective shields for electromagnetic interference (EMI) shielding in the microwave region. Electrical conductivity measurement revealed that NFC films loaded with PPy-NT (PPy-NT/NFC) exhibited the highest conductivity (1.16 S cm–1) compared to those loaded with C-PPy-NT or MWCNT. PPy-NT/NFC displayed the highest gravimetric capacitance among all tested films reaching 209.7 F g−1 at 10 mV s−1 in a stable potential window (from –0.5 to 0.15 V vs. MSE). When larger potential window (from –0.5 to 0.5 V vs. MSE) was applied, PPy-NT/NFC exhibited fast capacitance decay (to 80% of initial value in 50 cycles). The promising properties of PPy-NT/NFC electrode material were further confirmed in full-cell measurements in symmetric arrangement providing stable performance and 74 F g−1. Meanwhile, C-PPy-NT/NFC and MWCNT/NFC displayed significantly lower capacitances (below 20 F g−1 at 10 mV s−1) but better cycling stability in a larger potential window. The highest shielding efficiency of all NFC-based composites was observed in case of PPy-NT/NFC, reaching 75% in the C-band region.

Recent Advances in Multi-Scale Experimental Analysis to Assess the Role of Compatibilizers in Cellulosic Filler-Reinforced Plastic Composites

Adding acid-modified resin compatibilizers is essential for plastic composites reinforced with carbon-neutral cellulosic filler. Researchers have measured the efficacy of adding a compatibilizer in the context of mechanics. However, it is necessary to microscopically clarify how the compatibilizer actually works for quality control and further expansion of applications. In this review, the author first describes the situation of cellulosic composites and presents issues regarding how one assesses the role of the compatibilizer. The author then reviews recent multi-scale experimental approaches to the detection of covalent bonds between the cellulosic filler and compatibilizer, estimation of nanoscale interphases, and the micron-scale dispersibility of the fillers. With accumulation of such experimental facts, appropriate parameter settings can be expected for the structural analysis such as the finite-element method, as well as the potential to provide appropriate explanatory variables for material/process informatics.

The influence of crystalline structure of cellulose in chitosan-based biocomposites on removal of Ca(II), Mg(II), Fe(III) ion in aqueous solutions

In this work, the influence of the supermolecular structure of cellulosic fillers in chitosan matrix on the process of adsorption of calcium, magnesium and iron metal ion was analyzed, while using techniques such as: X-ray diffraction, flame atomic absorption spectrometry, FTIR spectroscopy, particle size analysis, and wettability angle. It has been shown that polymorphic form of cellulose significantly affects its particle size. The introduction of cellulosic filler into polymer matrix was responsible for changes in the sorption efficiency of chitosan composites. It was found that materials with nanocellulose II were characterized with the highest efficiency of adsorption. This interesting relationship has not been reported in the literature, yet. It is important especially in terms of designing composite materials with high adsorption capacity. In the presented paper this issue was discussed, taking into account crystallographic aspects as well as changes in the hydrophilicity of the surface of composite materials. Composite materials were also subjected to mechanical tests which showed some interesting increase in tensile strength when compared to the unfilled polymer.

Enhancing the mechanical performance of surface-modified microcrystalline cellulose reinforced high-density polyethylene composites

The microcrystalline cellulose (MCC) was successfully modified with a poly(ethylene-co-glycidyl methacrylate) copolymer (PEGMA) to be constructed the PEGMA anchored MCC (PEGMA-a-MCC). The chemical modification of the pristine MCC surface was confirmed by X-ray photoelectron spectroscopy (XPS) analysis. And then, the pristine MCC and PEGMA-a-MCC were successfully incorporated into the high-density polyethylene (HDPE) matrix by typical melt-mixing technique. When applied the PEGMA-a-MCC, interfacial adhesion performance between the cellulosic filler and HDPE matrix showed better and stronger than the pristine MCC. From the results of thermal behaviors and mechanical properties of the composites, it was possible to achieve enhanced their mechanical properties without change of thermal characteristics of HDPE matrix.

Influence of Walnut (<i>Juglans </i>L<i>.</i>) Shell Particles Addition on the Mechanical Properties of Epoxy Composites

The primary objective of this research work is to explore the potential of walnut shell particles as a reinforcing agent in the thermoset matrix composite. Therefore, the number of composite samples was developed by varying the filler weight percentage (15%, 25%, 35%, and 45%) in an epoxy polymer. The composite samples were characterized in terms of mechanical properties by using tensile test, flexural or three-point bending test, Izod impact test, compression test, and Rockwell hardness test. Moreover, the effect of cellulosic filler content on the density and water absorptivity of epoxy-based composites was also investigated as per the ASTM standard. Agricultural waste in the form of walnut shell was characterized by the determination of grain size. The experimental results showed that the stiffness and hardness of epoxy thermoset were increased with the decrease in tensile and flexural strength after the addition of walnut shell fine particles. The composite of 35 wt% walnut filler exhibits a balanced combination of strength, stiffness, and toughness. It was found that the mechanical strength and modulus of filled composites were increased with the increase of filler content up to 35 wt%.

Effect of cellulosic fillers addition on curing and adhesion strength of moisture-curing one-component polyurethane adhesives

Abstract In this work, microcrystalline cellulose (MCC) and sawdust (SD) green fillers have been demonstrated as reactive fillers and moisture reservoirs for enhanced curing and adhesion strength of one-component moisture-curing polyurethane (PU) adhesives. The chemical reaction between the MCC or SD fillers and isocyanates present in the PU adhesives was tracked using Fourier-transform infrared spectroscopy (FTIR), while the joint strength was determined using lap-shear tests. The results showed that the addition of MCC or SD leads to an accelerated curing rate through the early consumption of isocyanates. The lap-shear strength of unreinforced PU adhesive joints was achieved in 12 hours. In turn, the curing time in MCC and SD reinforced joints was achieved in 5 hours. The addition of MCC and SD fillers also enhanced the lap-shear strength of the joints under full cure conditions. An autocatalytic growth model was used to describe the lap-shear strength variation with respect to curing time.

The Effect of Alkali Treatment And Microcrystalline Cellulose Addition on Density Value of Cantala Fiber Reinforced Unsaturated Polyester Composites

<p>Natural fiber reinforced composites is one materials potentially developing in Indonesia. One of biggest problem with composites specimen is its void. One properties to find out void of composites is composites density value. The objective of research is to investigate the effect of fiber alkali (NaOH) treatment and microcrystalline cellulose (MCC) addition on density value of cantala fiber reinforced unsaturated polyester composites. Firstly, cantala fibers was submerged into alkali (NaOH) 6% solution for 0, 3, 6, 9, and 12 hours. Furthermore, the fiber was washed using acetid acid and then using clean water to reach pH 7. Thereafter, cantala fiber was dried in the oven for 10 hours at temperature 60<sup>0</sup>C. Composites was composed of cantala fiber, unsaturated polyester polymer matrix, and microcrystalline cellulose according to the composition with volume fraction 30%. Composites was casted using compression molding method with compressive strength of 10 MPa for 12 hours. All specimens of composites undertake post cure for 2 hours at 60<sup>0</sup>C. Density test was conducted using densimeter by calculating the density of composites in the air and the water. The result of research showed that the longer the alkali treatment time and the more addition of microcrystalline cellulose (MCC) filler, the higher is the composites density. The higher density value of cantala fiber reinforced unsaturated polyester is alkali treatment 6 hours, which was 1.223 gr/cm<sup>3</sup>.</p>

Superhydrophobic PVDF/micro fibrillated cellulose membrane for membrane distillation crystallization of struvite

Phosphate recovery is essential due to the depletion of phosphate resources and the phosphate loss by surface run-off. Membrane distillation crystallization (MDC) system with macroporous membrane provides a large interfacial surface for water removal at low temperature and phosphate concentration for crystal growth in the phosphate recovery strategy. However, the water vapour removal rate is limited by the membrane porosity and pore size. Membrane wetting and fouling on the hydrophobic membrane surface further reduce phosphate recovery in the long operation. In this work, polyvinylidene fluoride (PVDF) membrane was enhanced by adding micro fibrillated cellulose (MFC) filler to enhance phosphate recovery through struvite precipitation in MDC. The membrane was further modified by non-fluorinated silane (hexadecyltrimethoxysilane or octadecyltrichlorosilane) after phase inversion to attain superhydrophobicity. MFC promoted pore growth and porosity creation in PVDF/MFC membrane as the solvent-non-solvent exchange rate was boosted during phase inversion. In silane modification, abundant moieties of MFC further promoted vertical polymerization for creating superhydrophobic surface. The PVDF/MFC membrane modified with octadecyltrichlorosilane obtained the highest water contact angle of 154.4°, liquid entry pressure of 1.51 bar, relatively large pore size of 0.40 μm and satisfactory porosity of 45.1%, resulting in the stable permeate flux in MDC. The needle-like struvite crystals formed after pH adjustment and the modified membrane surface was not fouled even after 24 h of operation.

Effect of single-fiber properties and fiber volume fraction on the mechanical properties of Ioncell fiber composites

The present study concentrates on a series of experiments and numerical analyses for understanding the effects of fiber volume fraction ( VF) and draw ratio ( DR) on the effective elastic properties of unidirectional composites made from an epoxy resin matrix with a continuous fiber reinforcement. Lyocell-type regenerated cellulose filaments (Ioncell) spun with DRs of 3, 6, and 9 were used. In accordance with the specimens in situ, the fibers were modeled as slender solid elements, for which the ratio between the diameter and length was taken to be much less than unity and deposited inside the matrix with the random sequential adsorption algorithm. The embedded element method was thereafter used in the numerical framework due to its computational advantages and reasonable predictions for continuous fiber reinforced composites. Experiments and numerical investigations were carried out, the results of which were compared, and positive trends for both fiber VFs and DRs on the effective properties were observed. The presented experimental and numerical results and models herein are believed to advance the state of the art in the mechanical characterization of composites with continuous fiber reinforcement.

Improving electric insulation characteristics of PVA/V2C MXene composite high-dielectric-constant films by blending cellulose

Polymer/conductor composite dielectrics easily have high permittivity, high conductivity, and high dielectric loss, limiting large increase of energy storage density in them. The relationship between high permittivity and low conductivity is coordinated to achieve high energy density. In this study, polyvinyl alcohol (PVA)/V2C MXene/cellulose ternary composites with high permittivity and low dielectric loss were prepared. Due to good water solubility of PVA and high water dispersibility of V2C, PVA and V2C have good interfacial compatibility. That reduces the interface electric leakage conductance, which is conducive to the lower conductivity and dielectric loss in the composite materials. The high interfacial polarization between PVA and V2C improves the dielectric response of the composite materials, improving the permittivity of the composite materials. Compared with binary PVA/V2C composites, ternary PVA/V2C/cellulose composite materials use the high insulation of cellulose filler to increase the insulation of composites. Thus, the conductivity and dielectric loss are reduced in ternary composites. Good synergy of conductive V2C and insulating cellulose fillers is important to obtaining the balance of high dielectric response and high insulation trait in ternary composites. Best ternary composite with 6 wt% V2C has a high permittivity of ca. 40, low dielectric loss of ca. 0.25 at 100 Hz, and high breakdown strength of ca. 40 MV m−1. This work enables a facile preparation of promising composites for dielectric energy storage. • Novel ternary composite dielectric films with V 2 C MXene and cellulose were fabricated. • Good synergy of V 2 C and cellulose can lead to optimization of overall electric properties. • This work might provide ideas for preparing bio-dielectric materials employing cellulose.

Biodegradable gelatin composite hydrogels filled with cellulose for chromium (VI) adsorption from contaminated water

Biopolymers are promising materials for water treatment applications due to their abundance, low cost, expandability, and chemical structure. In this work, gelatin hydrogels filled with cellulose in the form of pristine eucalyptus residues (PER) or treated eucalyptus residues (TER) were prepared for adsorption and chromium removal in contaminated water. PER is a lignocellulosic compound, with cellulose, hemicellulose, and lignin, while TER has cellulose as a major component. FT-Raman Spectroscopy and FTIR analysis confirmed the crosslink reaction with glutaraldehyde and indicated that fillers altered the gelatin molecular vibrations and formed new hydrogen bonds, impacting the hydrogels' crystalline structure. The hydrogen bond energy was altered by the cellulosic fillers' addition and resulted in higher thermal stability (~10 °C). Hydrogels presented a Fickian diffusion, where gelatin hydrogel showed the highest swelling ability (466%), and composites showed lower values with the filler content increase. The chromium adsorption capacity presented values between 12 and 13 mg/g, i.e., featuring an excellent removal capacity which is related with hydrogel crosslinked structure and fibers surface hydroxyl groups, highlighting gelatin hydrogel TER 5% with better removal capacity. The developed hydrogels were produced from biomacromolecules with low-cost and potential application in contaminated water.

Effect of Flow Channel Configuration on Nano Fibril Alignment by Elongational Flow

Cellulose Nano-fibrils (CNFs) are the fundamental building blocks extracted from wood fibers and have gained great attentions as a novel biological material. It is known that the outstanding mechanical properties of cellulose filament made of CNFs can be obtained with their orientation inside the filament, the orientation control of CNFs is essential in the material fabrication. In this study, the effect of channel configuration on the orientation of CNFs by elongational flow are clarified both by numerical simulation and experiment. The higher CNF orientation parameter can be obtained for the channel with the focusing angle of 45 degrees compared to that with 90 degrees and also by increasing the flow rate ratio of downstream sheath flow to the upstream one. The ultimate tensile strength and toughness of cellulose filament increases by 11 % and 59 %, respectively by increasing flow rate ratio from 1.0 to 3.0 with 45 degrees focusing angle as predicted from the numerical simulation results.

Modification of cellulosic filler with diisocyanates – volatile organic compounds emission assessment and stability of chemical structure over time

AbstractThis paper investigated the impact of type and content of diisocyanate on the structure of modified cellulose fillers. Four the most popular isocyanates were applied – isophorone, hexamethylene, toluene and methylene diphenyl diisocyanate – at loadings of 1–15 wt%. Chemical structure, and its short-term storage stability, were investigated for eight weeks. Moreover, the main volatile organic compounds detected during modification, as well as emitted from fillers before and after storage, were identified. The main compounds detected in the air during modifications were terpenes and terpenoids. No diisocyanates were detected, which is very beneficial considering their toxicity. They were emitted from modified fillers at 40 °C, but only from fresh samples. After storage no emissions were noted, which indicated successful modification of fillers, also confirmed by FTIR spectroscopy and changes in polarity of fillers’ surface. Observed changes should be considered beneficial for the potential applications of modified fillers in manufacturing of polymer composites.

Fabrication of 3D-printed hygromorphs based on different cellulosic fillers

The aim of this work is to characterize the moisture-dependent actuation behavior of bioinspired and additively manufactured hygromorphs based by following deductive and inductive design approaches. Fused Filament Fabrication (FFF) is employed to print bilayered structures consisting of swellable active layers and rigid passive layers. The active layer is composed of a polylactic acid (PLA) matrix filled with different hygroscopic cellulosic materials (native and modified) up to a filler content of 50 m%. Acrylonitrile Butadiene Styrene (ABS) is used for the passive layer. The FFF process allows the generation of desired differential swelling properties in the composites upon moisture absorption. The moisture dependent actuation strain of the printed bilayers was determined by video analyses. Some influencing geometrical factors which contribute to the actuation were deduced from x-ray diffraction (XRD) and micro computed tomography (μCT). The investigation of the mean cellulose microfibril orientation on the surface of the active layer suggested a preferential orientation with respect to printing direction. Furthermore, a gradient of cellulosic material within a single printed layer was observed, which indicates fiber sedimentation. Comparison with the thermomechanical model derived from Timoshenko (1925) shows that the computational prediction of the moisture dependent actuation is considerably accurate for most selected cellulosic materials and filler contents.

Obtaining and Characterization of Biodegradable Composites Reinforced with Microcrystalline Cellulose Fillers

Obtaining and Characterization of Biodegradable Composites Reinforced with Microcrystalline Cellulose Fillers