Higher Crystallinity Index Research Articles

A holocellulose air filter with highly efficient formaldehyde adsorption prepared via low temperature pulping and partial dissolving from corn stalks

Emissions of particulate matter (PM) originating from industrial and agricultural incineration had emerged as a significant public health concern. Furthermore, the considerable annual production of straw remains underutilized, particularly in China. In this study, we proposed a novel approach for holocellulose air filter production from corn stalks via low-temperature anthraquinone pulping, partial dissolving, and high-speed shear-induced regeneration. About 61.40–78.23 % of hemicellulose in corn stalks was retained in holocellulose, furthermore, the delignification rate was up to 81.63–92.51 % after low temperature (<100 °C) alkaline exactment. Subsequently, holocellulose air filters (RHF) was prepared through regeneration with high-speed shear induced (25,000 rpm) and freeze-drying. The final air filters contained approximately 8.56–12.4 % hemicellulose, exhibiting a substantial adsorption capacity for low molecules such as formaldehyde. The results revealed remarkably low PM2.5 penetration ratio (0.12 %) and pressure drop (14.3 Pa) of the air filter, while exhibiting a remarkable formaldehyde adsorption capacity of 54.5 mg/g. Moreover, the characters of high crystallinity index and robust micro/nano-structure of regenerated cellulose were obtained. This study introduced an innovative and facile strategy for gaseous formaldehyde adsorption and introduced novel solutions for agricultural waste utilization.

Production and analysis of synthesized bacterial cellulose by Enterococcus faecalis strain AEF using Phoenix dactylifera and Musa acuminata fruit extracts.

Bacterial cellulose (BC) is a highly versatile biopolymer renowned for its exceptional mechanical strength, water retention, and biocompatibility. These properties make it a valuable material for various industrial and biomedical applications. In this study, Enterococcus faecalis synthesized extracellular BC, utilizing Phoenix dactylifera and Musa acuminata fruit extracts as sustainable carbon sources. LC-MS analysis identified glucose as the primary carbohydrate in these extracts, providing a suitable substrate for BC production. Scanning Electron Microscopy (SEM) revealed a network of BC nanofibers on Congo red agar plates. ATR-FTIR spectroscopy confirmed the presence of characteristic cellulose functional groups, further supporting BC synthesis. X-ray diffraction (XRD) analysis indicated a high crystallinity index of 71%, consistent with the cellulose I structure, as evidenced by peaks at 16.22°, 21.46°, 22.52°, and 34.70°. Whole-genome sequencing of E. faecalis identified vital genes involved in BC biosynthesis, including bcsA, bcsB, diguanylate cyclase (DGC), and 6-phosphofructokinase (pfkA). Antibiotic susceptibility tests revealed resistance to cefotaxime, ceftazidime, and ceftriaxone, while susceptibility to imipenem was observed. Quantitative assessment demonstrated that higher concentrations of fruit extracts (5.0-20mg/mL) significantly enhanced BC production. Cytotoxicity testing via the MTT assay confirmed excellent biocompatibility with NIH/3T3 fibroblast cells, showing high cell viability (97-105%). Unlike commonly studied Gram-negative bacteria like Acetobacter xylinum for BC production, this research focuses on Gram-positive Enterococcus faecalis and utilizes Phoenix dactylifera and Musa acuminata fruit extracts as carbon sources. This approach offers a sustainable and promising avenue for BC production.

Cellulose nanocrystal extraction from tissue paper wastes using different extraction methods and cellulose acetate production

ABSTRACT This paper examines the feasibility of extracting cellulose from tissue paper wastes (TPW’s) using several methods: sonication (SC), subcritical (SU), microwave (MC), and microwave with diluted acid (MA). The chemical characterisation and morphological properties of nanocrystal cellulose were investigated using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and scanning electron microscopy with energy dispersive X-Ray analysis (SEM-EDX). TPW’s have a relatively high crystallinity index (CrI = 61.02%). It was found to be lower than that for cellulose extracted using SU and SC MC, MA methods, where CrI to 65.65%, 68.07%, 69.21% and 73.42%, respectively. The MA method yielded cellulose with the highest CrI and altered surface morphology. This cellulose was selected for cellulose acetate synthesis. After acetylation, the CrI decreased to 61.45%, and the morphological aspect was changed. In conclusion, nanocrystal cellulose was successfully extracted from TPW’s and effectively changed to its esterified form.

Enhanced properties of low-density polyethylene composites reinforced with Bridelia ferruginea fibers: effect of low temperature fiber acetylation

In this study, lignocellulosic fibres were extracted from Bridelia ferruginea (BF), a shrub which can be found in sub-Saharan Africa with a view to probing the potential application of the fibres. The chemical properties of the BF were chemically modified by acetylation to evaluate the potential applications of the fibre reinforced polymer composites. The unacetylated and acetylated fibres were characterized using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD) and Thermogravimetric Analysis (TGA) to compare thermal and crystallographic properties after acetylation over different lengths of time. The acetylated fibres with the most promising properties were used for the fabrication of a polymeric composite. The mechanical properties of the fibre-reinforced polymer composites were studied by hardness and dynamic mechanical measurements. Four types of polymeric samples were prepared for the mechanical measurements: unreinforced polymer (Control) polyester, ATBF/LDPE, ACEBF3/LDPE, ACEBF/LDPE. The SEM micrographs revealed that acetylation led to defibrillation. FTIR peaks at 1250 cm−1 and 1371 cm−1 confirmed that acetylation had occurred. The fibres possessed high crystallinity index of 75% which reduced as time of acetylation increased. Acetylation at mild conditions of 70 °C for 3 h did not result in significant damage to the fibres. For the hardness measurements, the values of the micro-hardness of the composite samples increased from 0.20 GPa to 0.29 GPa. The acetylated fibres tend to further resist deformation due to its dispersion in the polymer matrix providing a stronger cross-linking effect. The properties unearthed show that BF appears to be a promising raw material for the production of polymer composites.

Impact of deep eutectic solvent pre-treatment on the extraction of cellulose nanofibers

Deep Eutectic Solvents (DESs) have emerged as promising eco-friendly pre-treatment agents for lignocellulosic biomass, offering considerable advantages for the nanofibrillation process. This study investigates the impact of DESs on cellulose fibers morphology, focusing on solubilization phenomena in the amorphous regions that may facilitate cellulose nanofiber production. The pre-treatment process combining a DES (triethylmethylammonium chloride and imidazole, TEMA:IMD) with microwave (MW) energy was optimized to enhance the solubility of cellulosic fibers. A response surface methodology (RSM) was employed to optimize the DES-MW-assisted pre-treatment. Results show that the reaction time and the temperature significantly influence the solubility of cellulosic fibers. The optimized conditions resulted in cellulose fibers with low content of hemicellulose and lignin, high crystallinity index, and improved thermal stability. The effectiveness of DES-MW pre-treatment in producing cellulose nanofibers (CNFs) from native and pre-treated fibers was investigated. Cellulose fibers pre-treated with a DES yielded CNFs with a narrower diameter distribution. Overall, optimized DES-MW pre-treatment offers a promising strategy for the efficient and sustainable extraction of CNFs.

Green and facile synthesis of cellulose nanofibres from Peltophorum pterocarpum pods cellulose using a eutectic solvent

ABSTRACT This study focuses on isolating, optimising and characterising cellulose from Peltophorum pterocarpum pods and synthesising cellulose nanofibres (CNF) using a eutectic solvent (ES). Three methods were evaluated: Soxhlet extraction, formic acid, and autoclave-assisted pre-treatment. The autoclave-assisted method yielded the highest cellulose content, approximately 43.6% w/w, at 121°C for 40 min. CP-MAS13C NMR and FTIR spectroscopy confirmed the cellulose’s carbon atoms and functional groups, and XRD analysis indicated a high crystallinity index (82.92%) and the transformation from cellulose I to cellulose II. SEM and TGA analyses assessed the morphological and thermal properties. CNFs were synthesised using a green solvent (ChCl/Lactic acid, 1:2) at 80°C, with TEM confirming their nanofibrous structure. The CNF zeta particle size was 262.1 nm, with a potential of −19.0 mV. The use of ES in the CNF synthesis is a novel and eco-friendly process that aligns with 5 of the 12 principles of green chemistry.

Characterization of Bacterial Nanocellulose Produced by Tropical Fruit‐Derived Bacteria in Coconut Water Medium Supplemented with Pineapple Peel Extract

AbstractAgro‐industrial residues, such as surplus fruits and vegetables are increasingly recognized as valuable sources for isolating bacterial strains capable of efficiently producing bacterial nanocellulose (BNC). This study presents a novel approach to BNC production using Komagataeibacter intermedius SB 110 isolated from rotten pineapple, cultivated in a sustainable medium of coconut water enriched with 5% sucrose and 0.5% pineapple peel extract. By leveraging agricultural waste, this method accelerates BNC biosynthesis to less than 7 days and achieves a yield of 5.563 g/L over 14 days, a 1.58‐fold increase compared with traditional media. The BNCs were primarily composed of cellulose type I, with minor cellulose type II, ultrafine fiber sizes (58.3 to 84.98 nm) and a high crystallinity index (60.81% to 78.34%), indicating superior structural quality. This innovative process not only demonstrates the potential of using low‐cost, sustainable substrates for high‐yield BNC production but also significantly enhances both the efficiency and scalability of the production process, setting a new standard over existing methods.

Biodegradable and antioxidant films with barrier properties to visible and ultraviolet light using Hass avocado (Persea americana Mill.) by-products

The search for renewable sources that can be used to develop products as alternatives to traditional polymers in the future, without affecting food safety, represents a challenge for the food industry. In this context, agro-industrial waste has emerged as an interesting alternative. This study evaluated biodegradable films made from Hass avocado seed flour without (Control film; PC) and with antioxidant extracts (PExBIO and PExIND) derived from the epicarp of the same fruit. The results showed that all the films blocked visible (over 96 %) and ultraviolet light (99.9 %), which was mainly attributed to perseorangine, a compound generated by the action of polyphenol-oxidase. The films also exhibited good water vapor barrier properties. PExIND showed the highest mechanical strength (Young's modulus = 901.8 ± 33.4 MPa; tensile strength = 9.1 ± 1.0 MPa; elongation = 3.5 ± 0.5 %), correlating with the highest crystallinity index (14.9 %). The incorporation of extracts increased the content of phenolic compounds and antioxidant capacity in PExBIO and PExIND compared to PC, with no significant differences between them. Moreover, the biodegradation test indicated that the films showed high biodegradability. Therefore, Hass avocado residues could be used to produce biodegradable antioxidant films, suitable for packaging light-sensitive and low-moisture products.

Ultrasound-assisted extraction of bioactives as a strategic step for chemical pretreatments in nanocellulose production from acerola by-products

Acerola by-products (AB) have been used as raw material for extracting active compounds; however, there were no studies related to the use of the remaining acerola by-product (RAB) from this extraction. This portion still has fibers and can be used for the production of cellulose nanofibrils (CNFs); therefore, the main objective of this study was to evaluate the production of CNFs using AB and RAB and to investigate whether the extraction can be a treatment step before bleaching/acid hydrolysis. AB and RAB were characterized before and after being chemically treated (AB_CT and RAB_CT, respectively). The fibers extracted from the RAB showed the highest cellulose contents (RAB: 36.6 % and RAB_CT: 69.9 %), suggesting that the extraction process had an impact on by-product defibrillation. The same trends were observed for CNFs produced by acid hydrolysis. CNFs based on RAB showed higher yield (CNF_RAB: 25.2 % and CNF_RAB_CT: 24.2 %), higher crystallinity index (CNF_RAB: 68.3 % and CNF_RAB_CT: 71.7 %) and higher thermal stability compared to CNFs extracted from AB and AB_CT. This study proved that it is feasible to use by-products after removing the active compounds for CNF production without other pre-treatments or in association with chemical treatment to obtain more crystalline and thermally stable CNFs.

Production of cellulose nano/microfibers through simultaneous milling and enzymatic hydrolysis with an optimized cocktail of cellulase/xylanase/LPMO

Cellulose nanofibers (CNF) and microfibrillated cellulose (MFC) are biodegradable micro and nanomaterials derived from plant cellulose. The properties of CNF, influenced by fibril length, impact the strength of cellulose-based nanomaterials. This study uses enzymatic milling to explore pretreatments, enzymatic optimization, and CNF/MFC production. The study found that hammer milling and lamination are effective pretreatments for preserving fibers. The optimal enzymatic mixture contained 75 % cellulase and 25 % xylanase, yielding 68.7 % and 2.86 %/h productivity, respectively. The addition of the LPMO enzyme increased the yield by 10–13 %, depending on its concentration. Enzymatic milling was introduced as an innovative approach to CNF production, reducing hydrolysis time and creating milder processing conditions. The combined process of ball milling and enzymatic hydrolysis on pre-ground pulp in the hammer mill achieved a maximum CNF yield of 45.83 % and productivity of 13.10 %/h. X-ray diffraction showed that the lamination-pre-treated pulp had a high crystallinity index of 84.34 %. Scanning electron microscopy revealed fibers with diameters ranging from 52 nm to 296 nm. These findings support the search for sustainable and eco-friendly alternatives to non-renewable resources, enabling sustainable CNF production at room temperature with reduced processing time.

Simultaneous removal of Ni2+ and Congo red from wastewater by crystalline nanocellulose - Modified coal bionanocomposites: Continuous adsorption study with mathematical modeling

Due to ultra-fast technological improvement and rapid urbanization nowadays, industries have generated a huge amount of wastewater that is discharged directly into the environment. Resulting in harsh damage to ecology and public safety/security by contaminating the ground/surface water sources. Therefore, it is very crucial to purify this wastewater before discharging/reusing. This study will be devoted to the latest enhancements along with the new route of production of the multifunctional Crystalline Nanocellulose-Modified Bituminous Coal (CNC-MC) bionanocomposites. Besides these, the significant implementation of the fabricated CNC-MC bionanosorbents for the simultaneous removal of Ni2+ and Congo red (CR) from bulk-scale industrial wastewater has been stated. Conversely, influential parameters like inlet concentration (25–45 ppm), flow rate (3–5 mL/min), and adsorbent bed height (0.2–0.8 cm) were explored. The bionanosorbents were characterized by using some state-of-the-art equipment such as FTIR-ATR, XRD, BET, FESEM, and TGA analysis, while the water samples were analyzed by AAS and UV-NIR techniques. Results suggested that the fabricated CNC-MC bionanocomposites possessed a considerable amount of active binding sites/functional groups, showed high thermal stability up to 700°C, and had a high crystallinity index (around 92.41 ± 0.009%). They revealed a noteworthy honeycomb-like mesoporous microstructure with a significant specific surface area. Due to these outstanding features, this multifunctional bionanosorbents has exhibited sensational adsorption performance. Meanwhile, the maximum removal efficiency and percentage were observed at approximately 328.7 and 478.3 mg/g, as well as around 67.95 and 76.65% for Ni2+ and CR. The experimental data was evaluated by three well-known column models, namely the Thomas, Adam-Bohart, and Yoon-Nelson models, and respectable agreement was found. That is similarly appropriate for the justification of the experimental breakthrough curve by supporting the Langmuir isotherm and 2nd-order reversible reaction kinetics. Hence, this novel CNC-MC bionanosorbent could be beneficially used to purify industrial wastewater in an economical and eco-friendly way for sustainable environmental safety.

Influence of relative humidity on carbon sequestration and crystal morphology of air lime: A sustainable building material

This study investigated the carbon sequestration potential of air lime by carbonation in two different relative humidity conditions. The carbonation rate and amount of carbon dioxide captured were quantified using weight gain and various analytical techniques. Samples cured in high relative humidity showed almost complete carbon capture by sequestering 94.8 % of carbon dioxide from atmospheric air within 56 days, with calcite crystal formation and a high crystallinity index. Similarly, samples cured in low relative humidity conditions showed slightly less carbonation around 83.8 % with different calcium carbonate polymorphs like aragonite and vaterite, along with amorphous calcium carbonate. Results demonstrated that carbonation of lime is a promising technology for carbon capture and utilization in buildings as non-load bearing mortars or plasters and could be used to reduce carbon dioxide levels in the atmosphere.

Comprehensive characterization of microcrystalline cellulose from lemon grass (Cymbopogan citratus) oil extraction agro-industrial waste for cementitious composites applications

Presently, the construction industry demands components that are exceptionally strong and long-lasting. The initial important construction material is concrete, which contains between 1 % and 2 % of air voids. The structural damage caused by water that enters through the air spaces are improved with filler material. Chemical filler materials are environmentally harmful; therefore, eco-friendly materials are selected for this study. The environmentally benign character of agro-waste byproduct usage is a driving factor in the field of research. Numerous uses can be found for waste materials, especially after they have been repurposed. We used a byproduct of an essential oil extraction company, an extract made from the leaves of lemon grass (Cymbopogan citrus), in our research. Alkalization, slow pyrolysis, acid hydrolysis, and bleaching are only some of the chemical treatments that could be used to easily extract microcrystalline cellulose from the discarded waste material. In our study the chemicals used are mild harmful to the environment and a surface reactant (linear alkyl benzene sulfonic acid) is utilised to bleach and purify the microcrystalline cellulose. Thermal analysis, scanning electron microscopy, transmission electron microscopy and Fourier transform spectroscopy were all used to learn more about the cellulose that had been extracted. The extracted cellulose powder comprises a high crystallinity index (68.14 %) and low crystallite size (5.13 nm) found using X-ray diffraction analysis. The smooth and porous surface is observable in scanning electron microscope analysis. The Differential scanning calorimeter curve shows the highest degradation temperature at 218.16 °C. The micro sized particles mostly range between 100 and 120 μm and are found using ImageJ. The surface roughness and permissible skewness of cellulose particles were examined using atomic force microscopy. The density of extracted cellulose is 1.092 g/cm3. The microcrystalline cellulose yield % was notably maximum (40.45 %). This cellulose was introduced in a M30 grade cement concrete as fillers up to 5 % by the weight of cement. The fresh and mechanical properties of the concrete was found to get improved with the addition of cellulose up to 3 %. As a result, the characteristics of cellulose boost its utility within the construction sector.

Gradient heating activated ammonium persulfate oxidation for efficient preparation of high-quality chitin nanofibers

APS is a cheap and eco-friendly oxidant which enables one-step extraction of nanochitin (NCh) from fishery wastes. However, it is challenging to improve the preparation efficiency and NCh quality simultaneously, owing to the uneven or uncontrollable oxidation. Herein, we propose a simple and controllable way to isolate chitin nanofibers (ChNFs) from squid pen by gradient heating activated (GHA)- ammonium persulfate (APS) oxidation. Compared to the isothermal activated (ITA)-APS oxidation, our strategy reduced the mass ratio of squid pen to APS from 1:45 to 1:6 and reaction time from 15 h to 8 h. Meanwhile, the as-prepared ChNFs exhibited high yield (91.5 %), light transmittance (98 % at 500 nm), crystallinity index (96.9 %), and carboxyl content (1.53 mmol/g). GHA-APS oxidation involved multiple continuous heating and isothermal stages. The former stimulates a moderate activation of APS and enhances the oxidation rate, while the latter provides a duration for surface chemistry. This non-isothermal heating facilitates the continuous decomposition of APS at a relatively high and consistent rate, thereby enhances its oxidation efficiency. Furthermore, green assessments indicate this method is simple, time-saving, eco-friendly and cost-effective. Overall, this work introduces a novel perspective for the industrial extraction of high-efficiency and high-quality nanomaterials.

Enhancing cellulose fiber properties from chromolaena odorata and anana comosus through novel pulping chemical mixtures

The production of cellulose with exceptional properties has led to the modification of chemical pulping methods and the development of newer chemical pulping methods. This study developed mixtures of sodium hydroxide, ethanol, and anthraquinone as new pulping chemicals to produce alpha-cellulose from pineapple leaves and Saim weed stems. The addition of anthraquinone was noticed to influence the pulp yield positively and the FTIR of all the cellulose has the characteristic cellulose bands. Calculated Total crystallinity index (TCI), (Lateral order index) LOI., and Hydrogen bond intensity (HBI) from the FTIR presented PLSHAEC (68.38 %) and SWSHQEC (67.74 %) having high crystallinity. From the XRD, the 2? by all the materials is attributed to cellulose I diffraction, and the crystallinity index aligned with FTIR determined crystallinity. The determined particle average diameter using ImageJ software showed that PLSHQEC 3.00 had the smallest value, followed by 5.17 for PLSHQC, 5.32 for SWSHQEC, and 6.03 for SWSHQEC. From the thermal analysis, the onset of the degradation of all the cellulose occurred at different temperatures: 247.10? (PLSHQC), 253.38? (PLSHQEC), 240.20? (SWSHQC) and 242.58? (SWSHQEC). The increase in yield, higher crystallinity index, and smaller fiber diameter of the cellulose demonstrated anthraquinone as a better additive to produce quality cellulose that would undergo easy chemical modification.

Experimental study on chemical and thermomechanical properties of concrete incorporating Washingtonia robusta fibres

The aim of this work is to provide a new composite material for applications in the thermal insulation of buildings. The composite was made with mortar reinforced with natural fibres extracted from the petiole of the Washington robusta (WR) palm tree. The fibres used were first chemically characterised by energy-dispersive X-ray spectroscopy, scanning electron microscopy, X-ray and infrared diffractometry spectroscopies alongside tensile testing to discover their morphological structure. Afterwards, the fibres were incorporated into mortar with mass percentages varying from 0 to 4% to determine experimentally the thermomechanical properties of the manufactured samples. The chemical findings indicated that WR fibres are rich in cellulose, hemicellulose and lignin, and possess a high crystallinity index, which enhances the mechanical properties and durability of the composite. The density obtained for the composite W2RC4% is 1305 kg/m3 and less than 2000 kg/m3; this composite can thus be classified as a lightweight concrete according to the standard NF EN 206 + A2/CN (2022). The thermal conductivity and thermal effusivity dropped by about 60% and 42%, respectively. Moreover, the WR reduces the compressive strength (76%) and the flexural strength (36%) to minimum values, respectively, of 5.9 MPa and 3.8 MPa. These values meet the mechanical requirements of lightweight concretes (&gt; 3.5 MPa).

Co-encapsulation of β-D-Galactosidase and Ascorbic Acid in the Milk Protein-Based Microcapsules: Optimization and Characterization

This research is aimed at preparing the β-galactosidase (βg) and vitamin C (VC) cocapsules stabilized by milk proteins. The effect of different independent parameters including core-coating ratio (10-100%), whey protein isolate (0 : 1), sodium caseinate (0 : 1), and ultrasound power (50-150 W) on physicochemical properties of microcapsules was investigated. The response surface methodology (RSM) defined the optimal conditions. Increasing the WPI values had different effects on the particle size and polydispersity index (PDI). The zeta potential values decreased by decreasing SC values. The βg had better encapsulation efficiency in comparison to VC. Increasing the core-coating ratio showed a negative effect on the enzyme activity. Among the test parameters, the core-coating ratio was effective on the viscosity of microcapsules. Two optimum conditions for co-encapsulation were determined as WPI, SC, core-coating ratio, and ultrasound power of 0, 1, 100%, and 79.4 W and 0.2, 0.8, 100%, and 75 W for microcapsules I and II, respectively. In the next step, the structural and morphological properties of the optimum samples were analyzed. The heterogeneous morphology of microcapsules was observed by SEM analysis. The formation of new interactions between wall materials, βg, and VC was confirmed by FT-IR analysis. XRD analysis revealed that the WPI-coated sample had a higher crystallinity index. Generally, the successful co-encapsulation of βg and VC exhibited the potential of the resultant microcapsules for the industrial production of VC fortified and lactose-free milk.

Morphology, Crystallinity and Thermal Properties of Nanocrystalline Cellulose Isolated of Sisal Fiber by Acid Hydrolysis-Ultrasonication

Nanocrystalline cellulose (NCC) from natural Agave sisalana (Sisal) fibers were isolated using a combination of chemical and mechanical processes. The chemical treatment begins with soaking the fiber in a sodium hydroxide (NaOH) solution with a concentration of 5 wt.% at a temperature of 90°C for 60 minutes. Then following by bleaching (fiber refining) using a hydrogen peroxide solution (H2O2) with a concentration of 3 wt.% (weight), at a temperature of 60°C, and pH of 10 for 30 minutes. It aims to eliminate the presence of hemicellulose and lignin contained in the fiber. Fibrillation Micro into nano Sisal fibers using sulfuric acid (hydrolysis process). Sulfuric acid (H2SO4) with 55 wt.% at temperature 60°C for 30 minutes produced NCC with a diameter of 5±1 nm (D) and a length of 260±10 nm (L), as seen using a TEM (transmission electron microscope). The web-like network structured shape of NCC results in a high aspect ratio (L/D) value is 52. The acid hydrolysis-ultrasonication process produced a high crystallinity index of 78.82% through the XRD (x-ray diffraction) test. The crystallinity and aspect ratio of NCC show that Sisal fiber is a suitable material as a filler for bio-nanocomposite materials. The maximum temperature (Tmax) of NCC decreased by 10°C due to sulfate ions attached to the cellulose structure, causing the thermal stability to drop from 348°C to 338°C.

Effect of different nanofillers incorporation on HDPE/LDPE films nanocomposite

The objective of this study was to develop polymeric films of high-density polyethylene (HDPE)/low-density polyethylene (LDPE) that comprise 1 wt% of different nanofillers, that is, either nanofibrillated cellulose (NFC), montmorillonite clay (MMT), or graphene nanoplatelets (GNPs); the polymeric films were developed with and without the inclusion of a coupling agent (CA). The results indicated that all the samples that comprised nanofillers exhibited, at least, an increase of 3 to 25°C compared with that of the matrix and demonstrated higher stability at the beginning of the thermal degradation, as verified using TGA. In the DSC analysis of the samples that contained GNPs had highest crystallinity index (55%), having as the consequent improvement in the mechanical properties and in the oxygen permeation. The incorporation of GNPs provided a 127.71% increase in deformation at break and a lower value in oxygen permeability with 50.06 mL.cm.(cm2.s.cmHg)−1, when compared to the polymeric matrix. It was concluded that all the different nanofillers tested promoted distinct improvements in HDPE/LDPE films nanocomposite. It can be inferred that these modifications are related to the chemical composition, size and morphology of each nanofiller. Thereby, it is indicated that with the use of each nanofiller one must be in accordance with the necessary demand of each composite film.

SURFACE FUNCTIONALIZATION OF KENAF FIBERS WITH LAUROYL CHLORIDE: EFFECTS OF ALKALINE PRETREATMENT METHOD

Surface functionalization of cellulose fibers is the current focus of research seeking to develop composite materials for various applications. One reason is the low compatibility of natural cellulose-based fibers with thermoplastic matrices for the production of wood-plastic composites. In this research, kenaf fibers (KF) were esterified with lauroyl chloride. Before the esterification reaction, two alkaline pretreatment methods were used: Bain-Marie at low temperature, and at high temperature and pressure in the digester. SEM results showed a smoother surface morphology after esterification. ATR-FTIR results confirmed the substitution of hydroxyl groups of cellulose with lauroylate functional groups. Increasing the carbon content in EDX spectroscopy further supported the successful esterification of kenaf fibers, which is in accordance with ATR-FTIR findings. Based on ATR-FTIR and EDX results, the Bain-Marie pretreatment method was more effective for the esterification reaction. According to the XRD results, the crystallinity index of the fibers slightly increased after esterification reaction. However, the fibers pretreated in the digester had a higher crystallinity index, which was related to efficient removal of amorphous regions due to higher temperature and pressure used in the digester process. This research showed that alkaline pretreatment in Bain-Marie was more effective for the surface functionalization of cellulose fibers than the digester process. These results can be applied in future research works for esterification of cellulose fibers.