Non-cellulosic Content Research Articles

Characterisation of alkali-treated novel cellulosic fibres derived from Dombeya Buettneri plant as a potential reinforcement for polymer composites

ABSTRACT The present study evaluates the influence of alkali treatment using 2, 4, and 8 wt.% sodium hydroxide concentration solutions on novel cellulosic fibres manually extracted from the bark of dombeya buettneri plant (DBF). Alkali-treated fibres were characterised through physical and mechanical properties determination, Fourier transform infrared spectroscopy, X-ray diffraction, quantitative chemical analysis, thermogravimetric analysis, and scanning electron microscopy. Quantitative chemical analysis revealed a significant increment in cellulose content, reaching 67 ± 1.7% in DBF treated with 4 wt.% NaOH solution, accompanied by substantial reductions in lignin and hemicelluloses as confirmed by FTIR spectroscopy. XRD analysis showed an improved crystallinity index of 80% and crystallite size of 2.64 nm for 4 wt.% alkali-treated DBF. Additionally, 4 wt.% alkali-treated fibres yielded peak values of breaking force (40 N) and breaking tenacity (181 cN/Tex). SEM analysis confirmed enhanced surface roughness post-treatment, an indication of enhanced fibre/matrix interlocking during composite fabrication, whereas TGA analysis reported improved thermal stability post-treatment. EDX analysis confirmed that the C/O ratio is proportional to alkali solution concentration, indicating effective removal of non-cellulosic contents. In conclusion, treating DBF with 4 wt.% NaOH concentration improves their physical, mechanical, and chemical properties, suggesting their potential for polymer composite applications.

Fenton-Based Treatment of Flax Biomass for Modification of Its Fiber Structure and Physicochemical Properties

The availability of a sustainable technique for degumming lignocellulose fibers is a challenge for the fiber processing industry. Removal of non-cellulosic content from lignocellulose fibers is essential for improving their mechanical and chemical properties, which makes the fibers more suitable for various applications. Herein, a catalytic Fenton-based oxidation process was employed to isolate microcellulose fibers from raw flax fibers. Various complementary methods such as FT-IR/NMR spectroscopy and TGA were used to obtain insight into the thermal behavior of the treated fibers. The morphology of the fibers was studied using Scanning Electron Microscopy (SEM), whereas the surface chemical properties of the fibers was evaluated by a dye-based adsorption method, along with a potentiometric point-of-zero-charge method. To obtain fibers with suitable properties, such as uniform fiber diameter, several Fenton reaction parameters were optimized: pH (7), reaction time (15 h), iron sulfate (2 wt.%), and hydrogen peroxide (10 wt.%). The results indicate that, under the specified conditions, the average diameter of the raw fibers (12.3 ± 0.5 µm) was reduced by 58%, resulting in an average diameter of 5.2 ± 0.3 µm for the treated fibers. We demonstrate that the treated fibers had a lower dye adsorption capacity for methylene blue, consistent with the smoother surface features of the treated fibers over the raw flax fibers. Overall, this study contributes to utilization of the Fenton reaction an efficient oxidation technique for the production of lignocellulose fibers with improved physicochemical properties, such as reduced fiber diameter distribution, in contrast with traditional alkali-based chemical treatment.

Non-Wood paper from coffee pulp Waste: How its performance as coffee filter

Coffee pulp waste was having potential to be used as a source of non-wood cellulose for papermaking because of its abundance, considerable fraction of cellulose content, and low economic value. In this study, the isolated cellulosic fiber from coffee pulp waste was prepared into paper with the specific purpose of filter for coffee, with the aim as an effort to develop economic value and potential alternative utilization to reduce the environmental impact of coffee pulp waste accumulation, besides suggesting alternative non-wood cellulose source for coffee filter paper. The effect of extraction process repetition using 3 % (w/w) sodium hydroxide was studied to evaluate its effectiveness in removing the non-cellulosic content of coffee pulp, especially lignin, which could damage the taste of coffee. The physical and mechanical properties and water flow ability of coffee pulp filter paper (CPFP) were conducted to evaluate its characteristics and performance. The result showed that three times repetitions of alkali treatment to coffee pulp produced similar lignocellulosic content quality to the commercial wood-based coffee filter paper, with cellulose fraction reaching 86.67 % and residual lignin around 5.39 %. The coffee pulp-based filter paper made from three times repetition of alkali-treated coffee pulp has comparable tensile strength and excellent folding resistance compared to commercial filter paper, which reached around 526 ± 198.4 N/m and 1 df, respectively. The coffee pulp-based filter paper also demonstrated could withstand discharged through by boiling water without breaking. According to the resulting performance of CPFP, coffee pulp waste is promising to be further developed as an alternative non-wood resource for coffee filter paper manufacturing.

Ozone assisted modification and pulverization of plant fibres

The present work investigated the effect of ozone treatment on surface modification and pulverization of plant fibres. The surface of jute, sisal, and corn husk fibres was modified by ozone treatment to remove the non-cellulosic contents and thereby improve their pulverization by ball milling process for extraction of cellulose micro/nano fibrils. The surface morphology, physical appearance, hydrophilicity, and mechanical properties of plant fibres were examined before and after the ozone treatment. Among all plant fibres, the ozone treatment of corn husk fibres was found to remove lignin and increase hydrophilicity to greater extent, however with higher tendency of defibrillation and fibre rupture. The maximum drop in tensile strength was seen in case of corn husk fibres followed by sisal and jute fibres after the ozone treatments. The tensile strength was reduced by 70%, 60%, and 47% in case of corn husk, sisal, and jute fibres respectively after 15 min of ozone treatment. When pulverization of plant fibres was carried out in ball milling, the ozone treatment was observed beneficial for easier defibrillation of cellulose micro/nano fibrils. The pulverization of jute, corn husk and sisal fibres produced the particles with diameter of 610 nm, 380 nm, and 530 nm after 15 min of ozone treatment respectively.

Creep behaviour of ozone treated jute fabric/epoxy composites filled with ozonized and pulverized corn husk particles

In present work, the creep performance of ozone treated jute fabric/epoxy composites was studied at different environment temperatures after incorporation of 1, 3 and 5 wt % of ozonized and pulverized corn husk particles. The ozone treatment of jute fabric as well as corn husk fibres was found successful in removal of non-cellulosic contents. Furthermore, the ozone treatment of corn husk fibres was observed beneficial during ball milling as it easily pulverized them into particles due to decrease in strength. When the creep behaviour of composites was investigated using several creep models (i.e., Findley's power law model, Burger's model, and Coupling Model), the incorporation 3 wt % corn husk particles was found to reduce the creep deformation and strain rate of composites to greater extent especially at higher temperatures. The 3 wt % corn husk particles were found to restrict the segmental mobility of epoxy matrix in extended temperature range of 100 °C–140 °C. Nevertheless, the microbead pull out and nanoindentation tests indicated that the interfacial shear strength properties of composites increased after the incorporation of 5 wt % of corn husk particles. Among various creep models, the coupling model predicted the creep behaviour of composites more accurately in addition to explanation on the creep mechanism.

Effect of Surface Modification of Himalayan Nettle Fiber and Characterization of the Morphology, Physical and Mechanical Properties

Abstract The process of retting bast fiber plants for the production of long fiber has presented major challenges. Water retting, dew retting, chemical extraction, and micro-organism (fungi, enzymes) techniques were applied to the extraction of natural fibers. The two nettle samples were extracted with water retting for 14 days and dew retting for 4 weeks. This research investigated the effects on the traditional retting process of nettle fiber by fungi and bacteria formation in lignocellulosic. The latter biological extraction methods successfully degraded the lignin and pectin materials of the fiber and increases the cellulose content. These extraction methods produced high quality fiber and tensile strength at a low cost. This study determined the chemical, physical, and mechanical characteristics such as fiber cellulose, non-cellulosic content, tensile strength, tenacity, and elongation break to see how treatments affected them. The treated fiber surface morphology was characterized using scanning electron microscopy. To evaluate functional group alterations, Fourier-transform infrared spectroscopy was used on the fiber specimen.

One-step extraction of ramie cellulose fibers and reutilization of degumming solution

Ramie cellulose fibers are common natural fibers with high strength and outstanding biodegradability. However, there are interconnected gummy components covering raw ramie, which need to be removed to extract separated fibers. Here, an effective and environmentally friendly extraction approach using deep eutectic solvent (DES) was developed. The whole degumming technique can be completed in a one-step boiling process at 160°C for 2.5 h. This new method exhibited the capability to remove most non-cellulosic contents without sacrificing the physical properties or chemical structures of cellulose in comparison with the traditional alkaline method. Besides, the DES can be reutilized many times while still maintaining sufficient degumming efficiency. Some by-products in the degumming solution, such as lignin and polysaccharides, can be successfully separated, beneficially realizing recycling economy and sustainable development. The DES degumming method provides an alternative and practical method for ramie fiber extraction.

Yarn quality analysis in non-cellulosic and metal contents of cotton fibre of various locations

The fibre physical properties can be influenced by non-cellulosic and metal contents present in it which ultimately may impact the quality and spinning performance of resultant yarn. The concentration of these materials largely depends upon cotton variety, growing area and atmospheric conditions. In this back drop the present research study was planned to investigate the impact of various varieties and locations on non-cellulosic and metal contents of raw cotton and their eventual effects on subsequent yarn quality. So four varieties of single-season upland cottons from four different cotton-growing locations in Pakistan were selected for the study. The collected cotton samples were subjected to chemical and physical testing to know the concentrations of non-cellulosic and metal contents present in them along with other physical parameters. Then they were subjected to yarn manufacturing by conventional ring spinning method. At the end the yarn quality testing was carried in respect of its tensile and imperfections characteristics. The results disclosed significant impacts of selected variables on yarn quality. The reduction in non-cellulosic contents and metal contents put negative impact on Count Lea Strength Product (CLSP), yarn lea strength, single yarn strength, breaking length, evenness, thin spots, and neps count of resultant yarn.

Study on the Characteristics of Cottonized Indian Industrial Hemp Fibers

ABSTRACT Hemp fiber is one of the natural bast fibers, mainly obtained from the hemp plant with the species of Cannabis sativa(L). In recent time, hemp fibers have received wide applicability in composite materials on account of their sustainability and low density compared with manmade fibers. Hemp fibers also have inherent mechanical, acoustic, thermal, and physical properties. Industrial hemp is a genetically modified form of C. sativa(L) plant containing low THC (Δ-9 Tetrahydrocannabinol) value of below 0.3%. In this study, an attempt has been made to cottonization of Indian industrial hemp fiber. The fibers were given an alkali treatment for the removal of non-cellulosic content. Three different levels of concentration, time and temperature were selected for the treatments on the Box-Behnken response surface design principle. The effect of alkali treatment on mechanical properties viz; length, strength, and weight loss and physical properties viz; diameter, surface were analyzed. This process has eliminated the Indian traditional tedious water retting and time-consuming process used on Hemp fibers. The resultant fiber obtained from the proposed process is textile grade quality and spinnable by the cotton dry spinning system. The effect of alkali treatment on the mechanical and physical properties was found significant.

Analysis of properties on chemical treatment of kenaf fibers

In the present study, kenaf fibers were treated with sodium acetate at varying chemical concentrations (10%, 15% and 20%) for different treatment time. The investigation was carried out to study the effect of chemical treatment on chemical and thermal properties of kenaf fiber and its composites. Fourier transform infrared spectroscopy was performed to detect the removal of non-cellulosic content from kenaf fiber after chemical treatment. Glass transition temperature and specific heat capacity of treated and untreated fibers reinforced composites can be obtained by differential scanning calorimeter. The crystallinity and average crystallinity size of the developed composites were evaluated by XRD. The exhibited results show that the effect on physical and chemical properties were due to the removal of non-cellulosic content from fiber after chemical treatment.

Old corrugated box (OCB)-based cellulose nanofiber-reinforced and citric acid-cross-linked TSP–guar gum composite film

Old corrugated box (OCB) as a raw material was treated using alkali, acetic acid with NaClO and hydrogen peroxide to extract partially purified cellulose microfibers. FTIR and XRD analysis indicates the significant removal of non-cellulosic (lignin and hemicelluloses) content, followed by a notable increase in cellulose purity and crystallinity. Obtained cellulose microfibers (diameter 60–70 µm) were broken down to cellulose nanofibers (diameter up to 80 nm) using high-pressure homogenizer at 1700–1800 bar pressure consisting of 30 cycles and further characterized by SEM and XRD. Later on, nanocomposite films were prepared and optimized for required citric acid concentration for cross-linking with tamarind seed polysaccharide/guar gum blend by polycondensation reaction. And plasticized by glycerol (0.5% w/v) with different concentrations of OCB-CNF (0.1–1% w/v). The cross-link reaction was optimized at 80 °C for 3 h in order to confirm the esterification reaction between citric acid, polysaccharide and nanofiber. Increasing characteristic band intensity at around 1731 cm−1 represents ester bond formation is supported by the FTIR analysis. Rheology reveals the increase in cross-linking density after citric acid cross-link at 0.2% of OCB-CNF. Improvement in interfacial bonding between nanofiber and matrix results in enhanced tensile strength, barrier property and thermal stability as compared to those of control film. In addition, swelling behavior of OCB-CNF composite films was studied at different pH conditions (pH = 3, 7 and 10), where 0.2% and 0.5% OCB-CNFs showed better interaction with the matrix polysaccharide.

Features of the resource species Miscanthus sacchariflorus (Maxim.) Hack. when introduced in West Siberia

Here we provide a scientific justification and experimental support for the choice of easily renewable cellulosic feedstock Miscanthus sacchariflorus (Maxim.) Hack. in order to obtain high-quality nutrient broths therefrom for bacterial cellulose biosynthesis. The plant life-forms promising for breeding were screened under introduction conditions at the Central Siberian Botanical Garden, SB RAS, and this study was thus aimed at investigating the full and reduced ontogenetic patterns; cellulose and noncellulosic contents, including lignin; and duraminization of vegetative (feedstock source) organs throughout the seasonal development. The full ontogenetic patterns of the plants grown from seeds that had been collected in native habitats were compared to show that M. sacchariflorus and M. sinensis Anderss. accessions are distinguished by longer being at the most vulnerable developmental stages: seedlings and plantlets. Hence, it is preferable to cultivate seedlings on protected ground, and plantations are advisable to establish with more stable cloned vegetative material. The chemical compositions of the whole plant, leaf and stem separately, from seven M. sacchariflorus harvests were examined to reveal a rise in cellulose content and a drop in noncellulosic content with plantation age. The Miscanthus stem was found to contain more cellulose than the leaf, regardless of the plant age. The overall cellulose content was 48−53 %, providing a rationale for studies of bacterial cellulose biosynthesis in a M. sacchariflorusderived nutrient medium. Since high lignin content is undesirable for technological processes concerned with biosynthesis of bacterial cellulose, we performed histochemical assays of transverse sections of the culms to monitor the seasonal course of lignification. Our results suggest that the specific time limits for harvesting the aboveground biomass as a feedstock be validated by histochemical data on the seasonal course of lignification of M. sacchariflorus sprouts. To sum up, the examined chemical composition of M. sacchariflorus grown in the Siberian climate conditions demonstrated its prospects as a source of glucose substrate, the basic component of good-quality nutrient media for biosynthesis of bacterial cellulose.

Structure and properties of high quality natural cellulose nano fibrils from a novel material Ficus natalensis barkcloth

We report for the first time the extraction of cellulose nano fibrils from Ficus natalensis barkcloth fibers by means of chemical treatments and catalytic oxidation of cellulose fibers by using 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO). After every stage of treatments, the structural properties of barkcloth fibers powder (BC-PW), cellulose fibers (BC-NB) and cellulose nano fibrils (BC-CNF) were carefully characterized by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) for morphological analysis, Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction techniques for chemical analysis, and thermal properties were done by thermo-gravimetric analysis. FTIR results revealed the progressive removal of non-cellulosic contents and X-ray diffraction (XRD) analysis showed that the crystallinity increased with the successive alkali and bleaching treatments. Finally, by evaluating the TEM images, the average diameter of the nano-cellulose fibrils from Ficus natalensis barkcloth was also confirmed as 28 ± 0.6 nm and the length in hundred nano meters was recorded. The resultant cellulose nano fibrils maintaining the cellulose I structure had dimensional properties in nano-scale, higher crystallinity (68.5), and better thermal stability (305.62°C). The barkcloth cellulose nano fibrils can be used in nano technology like food packing material, nano composites and medical textiles.

Variation of the milling conditions in the obtaining of nanocellulose from the paper sludge

This work aimed to evaluate three different milling conditions, seeking the optimization of CNS isolation process. The paper sludge was chemically treated with detergent and H2O2, by two steps, to remove the noncellulosic contents (hemicellulose and lignin). After these treatments, the sample was milled with the variation of a liquid medium. The three liquids milling medium were: i) dry medium (CNS-D); ii) moist with water and (CNS-W) iii) moist with ethanol (CNS-E). The CNSs were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), zeta potential and dynamic light scattering (DLS). The milled samples presented different behavior, depending on the medium applied. The CNS-W presented low efficiency due to the formation of agglomerates around the ceramic ball, resulting in larger fiber sizes (microsizes). Although, the samples CNS-D and CNS-E presented similar behavior of sizes distribution, with average size 340 nm and 373 nm, respectively, determined by DLS. The CNS-E sample presented higher yield and electrostatic stability in solution, besides not presenting loss of crystallinity, as occurred with CNS-D, observed by FTIR analysis. Thus, the isolation with ethanol showed more efficient process among the three processes studied. This work achieved the isolation of CNS; besides, it proposed an environmentally friendly isolation method, and this may add value in the paper sludge. Keywords: industrial residue, cellulose nanostructures, ball mill, cellulose characterization.

Combining organosolv pretreatment with mechanical grinding of sugarcane bagasse for the preparation of nanofibrillated cellulose in a novel green approach

The production of nanofibrillated cellulose (NFC) from bagasse was optimized through a novel green approach by combining an organosolv pretreatment with microgrinding. Bagasse was processed through organosolv pretreatment with trifluoroacetic acid (OPT) as a catalyst to provide precursor fibers with full control of chemical components for NFC production. The mass balance of the pretreated bagasse through OPT (OPTB) was determined by its chemical components and total organic carbon analysis. OPT was found to be an efficient and energy-saving strategy for recovering cellulose, as well as hydrolyzing hemicellulose and lignin. Noncellulosic contents in OPTB fibers were optimized to obtain a high NFC yield through microgrinding. The highest NFC yield relative to the mass of precursor fibers of 72% was achieved through mechanical defibrillation of the OPTB containing noncellulosic content of 29%, which generated nanofibrils with the average diameter of 9 nm. In biorefinery principles, OPT not only converted 57% of bagasse to solid cellulosic fibers for NFC preparation, but also 30% of bagasse to valuable bioproducts including the hemicellulose-derived xylose (19%) and lignin-derived organosolv lignin (11%). The combined OPT and microgrinding produced NFC and simultaneously extracted bioproducts from bagasse while using easily recoverable and low environmental impact reagents.

Characterization of Cellulose Nanocrystals Extracted from Sugarcane Bagasse for Potential Biomedical Materials

Cellulose nanocrystals (CNCs) were extracted by sulfuric acid from cellulose purified via an environmentally friendly method. In this study, cellulose obtained from sugarcane bagasse (SCB) using steam-exploded and enzyme-treated pretreatment was confirmed using chemical composition analysis to have a 92.59 ± 0.12 whiteness index and 87% α-cellulose content. The morphology of extracted CNCs, characterized using atomic force microscopy images, transmission electron microscopy images and energy-dispersive x-rays, showed the diameter and length were in the ranges 9.8 ± 6.3 and 280.1 ± 73.3 nm, respectively, with an expected ratio (L/d) of 20–25 and a low concentration of sulfate (0.2%) on surface particles. Moreover, fourier transformed infrared spectroscopy and X-ray diffraction results demonstrated free noncellulosic contents and an improved crystallinity for CNCs, respectively. A decrease in the thermal stability of CNCs was examined by thermogravimetric analysis, and no evidence of cytotoxicity in the CNCs was obtained. The isolated CNCs from SCB may be considered as a potential biomedical material.

Reinforcement of ozone pre-treated and enzyme hydrolyzed longer jute micro crystals in poly lactic acid composite films

Abstract In present study, jute fibers were pre-treated with ozone gas to remove the lignin. The effect of ozone treatment on change in single fiber strength, fiber surface morphology, whiteness, moisture absorbency, etc was studied. For comparison purpose, chemical pre-treatment of jute fibers was also carried out. In subsequent step, untreated, chemical and ozone pre-treated jute fibers were hydrolyzed by cellulase enzymes for separation of longer jute micro crystals. The influence of non-cellulosic contents on the enzyme hydrolysis and morphology of obtained micro crystals was presented. Later, 3 wt% of these jute micro crystals were incorporated into poly (lactic acid) matrix to prepare composite films by solvent casting. The reinforcement behavior was evaluated from tensile tests, dynamic mechanical analysis, and differential scanning calorimetry.

Influence of noncellulosic contents on nano scale refinement of waste jute fibers for reinforcement in polylactic acid films

In the present study, nanofibrils of cellulose are extracted from waste jute fibers using high energy planetary ball milling process in wet condition. The rate of refinement of untreated fibers having non-cellulosic contents was found slower than treated fibers due to strong holding of fiber bundles by non-cellulosic contents. At the end of three hours of wet milling, untreated fibers were refined to the size of 850 nm and treated fibers were refined to the size of 443 nm. In the subsequent stage, composite films of poly lactic acid (PLA) were prepared by solvent casting with 3 wt% loading of untreated jute nanofibrils, treated jute nanofibrils and microcrystalline cellulose. The influence of non-cellulosic contents on mechanical properties of PLA films are investigated based on results of tensile test, dynamic mechanical analysis and differential scanning calorimetry. The maximum improvement was observed in case of treated jute nanofibril/PLA composite film where initial modulus and tensile strength increased by 207.69 % and 168.67 %, respectively as compared to neat PLA film. These improvements are attributed to the increased interaction of treated jute nanofibrils with PLA matrix due to their higher precentage of cellulosic contents and mechanically activated surface.

Conversion of lignocellulosic biomass to nanocellulose: structure and chemical process.

Lignocellulosic biomass is a complex biopolymer that is primary composed of cellulose, hemicellulose, and lignin. The presence of cellulose in biomass is able to depolymerise into nanodimension biomaterial, with exceptional mechanical properties for biocomposites, pharmaceutical carriers, and electronic substrate's application. However, the entangled biomass ultrastructure consists of inherent properties, such as strong lignin layers, low cellulose accessibility to chemicals, and high cellulose crystallinity, which inhibit the digestibility of the biomass for cellulose extraction. This situation offers both challenges and promises for the biomass biorefinery development to utilize the cellulose from lignocellulosic biomass. Thus, multistep biorefinery processes are necessary to ensure the deconstruction of noncellulosic content in lignocellulosic biomass, while maintaining cellulose product for further hydrolysis into nanocellulose material. In this review, we discuss the molecular structure basis for biomass recalcitrance, reengineering process of lignocellulosic biomass into nanocellulose via chemical, and novel catalytic approaches. Furthermore, review on catalyst design to overcome key barriers regarding the natural resistance of biomass will be presented herein.

Polylactic Acid (PLA) Composite Films Reinforced with Wet Milled Jute Nanofibers

In the present study, waste jute fibers formed in textile industries were wet pulverized to nanoscale using high energy planetary ball milling. The rate of refinement of uncleaned jute fibers having noncellulosic contents was found slower than the cleaned jute fibers. This behavior is attributed to the strong holding of fiber bundles by noncellulosic contents which offered resistance to the defibrillation during wet milling. In addition, the pulverization of fibers in the presence of water prevents the increase in temperature of mill which subsequently avoided the sticking of material on the milling container. After three hours milling, the diameter of nanofibers was observed around 50 nm. In the further stage, obtained nanofibers were incorporated under 1 wt%, 5 wt%, and 10 wt% loading into polylactic acid composite films. The potentials of jute nanofibers were investigated for improvement in mechanical and barrier properties of films. The maximum improvement in mechanical properties was observed in case of 5 wt% composite film where Young’s modulus was increased to 3.3 GPa from 1.0 GPa as compared with neat PLA film.