scholarly journals Cellulose Nanocrystals from Fibers of Macauba (Acrocomia Aculeata) and Gravata (Bromelia Balansae) from Brazilian Pantanal

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1785 ◽  
Author(s):  
Ana Carolina Corrêa ◽  
Vitor Brait Carmona ◽  
José Alexandre Simão ◽  
Fabio Galvani ◽  
José Manoel Marconcini ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Acid Hydrolysis ◽  
Cellulose Nanocrystals ◽  
Cellulose Degradation ◽  
Crystallinity Index ◽  
Palm Tree ◽  
Cellulose Content ◽  
Hydrolysis Time ◽  
Brazilian Pantanal

Cellulose nanocrystals (CNC) were obtained from macauba and gravata fibers. Macauba (or Bocaiuva) is a palm tree found throughout most of Brazil and Gravata is an abundant kind of bromelia with 1–2m long leaves, found in Brazilian Pantanal and Cerrado. The raw fibers of both fibers were mercerized with NaOH solutions and bleached; they were then submitted to acid hydrolysis using H2SO4 at 45 °C, varying the hydrolysis time from 15 up to 75 min. The fibers were analyzed by X-ray diffraction (XRD), FTIR Spectroscopy, scanning electron microscopy (SEM) and thermal stability by thermogravimetric analysis (TG). XRD patterns did not present changes in the crystal structure of cellulose after mercerization, but it was observed a decrease of hemicellulose and lignin contents, and consequently an increase of cellulose content with the increase of NaOH solution concentration in the mercerization. After acid hydrolysis, the cellulose nanocrystals (CNC) were also analyzed by transmission electron microscopy (TEM) which showed an acicular or rod-like aspect and nanometric dimensions of CNC from both fibers, but the higher values of aspect ratio (L/D) were found on CNC obtained from gravata after 45 min of acid hydrolysis. The mercerization and subsequent bleaching of fibers influenced the crystallinity index and thermal stability of the resulting CNC, but their properties are mainly influenced by the hydrolysis time, i. e., there is an increase in crystallinity and thermal stability up to 45 min of hydrolysis, after this time, both properties decrease, probably due to the cellulose degradation by the sulfuric acid.

scholarly journals Recycling Waste Cotton Cloths for the Isolation of Cellulose Nanocrystals: A Sustainable Approach

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 626
Author(s):  
Siti Hajar Mohamed ◽  
Md. Sohrab Hossain ◽  
Mohamad Haafiz Mohamad Kassim ◽  
Mardiana Idayu Ahmad ◽  
Fatehah Mohd Omar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cellulose Nanocrystals ◽  
Value Added ◽  
Crystallinity Index ◽  
Attenuated Total Reflection ◽  
Cellulose Content ◽  
Scanning Calorimetry ◽  
Good Thermal Stability ◽  
Alkaline Pulping ◽  
Hydrolysis Of Cellulose

There is an interest in the sustainable utilization of waste cotton cloths because of their enormous volume of generation and high cellulose content. Waste cotton cloths generated are disposed of in a landfill, which causes environmental pollution and leads to the waste of useful resources. In the present study, cellulose nanocrystals (CNCs) were isolated from waste cotton cloths collected from a landfill. The waste cotton cloths collected from the landfill were sterilized and cleaned using supercritical CO2 (scCO2) technology. The cellulose was extracted from scCO2-treated waste cotton cloths using alkaline pulping and bleaching processes. Subsequently, the CNCs were isolated using the H2SO4 hydrolysis of cellulose. The isolated CNCs were analyzed to determine the morphological, chemical, thermal, and physical properties with various analytical methods, including attenuated total reflection-Fourier transform-infrared spectroscopy (ATR-FTIR), field-emission scanning electron microscopy (FE-SEM), energy-filtered transmission electron microscopy (EF-TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The results showed that the isolated CNCs had a needle-like structure with a length and diameter of 10–30 and 2–6 nm, respectively, and an aspect ratio of 5–15, respectively. Additionally, the isolated CNCs had a high crystallinity index with a good thermal stability. The findings of the present study revealed the potential of recycling waste cotton cloths to produce a value-added product.

scholarly journals Influence of Hydrolysis Conditions on Characteristics of Nanocrystalline Cellulose Extracted from Ramie Fibers by Hydrochloric Acid Hydrolysis

2020 ◽  
Author(s):  
Kusmono Kusmono ◽  
Dimas Abdillah Akbar
Keyword(s):  
Thermal Stability ◽  
Hydrochloric Acid ◽  
Acid Hydrolysis ◽  
Acid Concentration ◽  
Crystallinity Index ◽  
Hydrochloric Acid Concentration ◽  
Hydrolysis Time ◽  
Study Results ◽  
Ramie Fibers ◽  
Hydrolysis Conditions

Abstract Nanocrystalline celluloses (NCCs) were successfully extracted from ramie fibers using chemical pretreatments followed by hydrochloric acid hydrolysis. The effects of acid concentration and hydrolysis time on the characteristics of NCCs were investigated in this study. Results showed that the optimal hydrolysis conditions were found to be 6 M hydrochloric acid concentration at 45 °C for 70 min. The obtained NCC had a rod like-shape with an average of 8.07 nm in diameter, 158.51 nm in length, 22.37 in aspect ratio, 89.61% in the crystallinity index, and 5.81 nm in crystallite size. The higher crystallinity and thermal stability were exhibited by NCCs compared to both raw fibers and chemically purified cellulose. The hydrolysis time had a significant effect on crystallinity and thermal stability. The crystallinity index and thermal stability of NCCs were obtained to decrease with increasing hydrolysis time.

Microscopic Characterization of Cellulose Nanocrystals Isolated from Sisal Fibers

2015 ◽  
Vol 827 ◽  
pp. 174-179 ◽  
Author(s):  
Harini Sosiati ◽  
Mu'minul Muhaimin ◽  
Purwanto ◽  
Dwi Astuti Wijayanti ◽  
Harsojo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Acid Hydrolysis ◽  
Cellulose Nanocrystals ◽  
Crystallinity Index ◽  
Xrd Analysis ◽  
Air Cooling ◽  
Residual Lignin ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Sisal Fibers

Isolation of cellulose nanocrystals (CNCs) was carried out by unrepeated or repeated alkalization and bleaching followed by sulfuric acid hydrolysis and air cooling (unrepeated) or ice cooling (repeated). The influence of unrepeated and repeated alkalization and bleaching, and cooling rate (cooling medium) after hydrolysis on the morphology and crystallinity of the isolated micro- and nano-celluloses were characterized. Scanning electron microscopy (SEM) showed that repeated alkalization and bleaching led to a higher degree of fibrillated microcellulose (~10 mm) with higher surface roughness than unrepeated alkalization and bleaching. Transmission electron microscopy (TEM) revealed that air and ice cooling after acid hydrolysis producing different CNCs morphologies; heterogeneous CNCs nanowhisker and nano-spherical (~50 nm), and homogenous CNCs nanowhiskers (~50 nm width and ~500 nm length), respectively. The homogeneous nano whisker was related to single phase monoclinic b-cellulose. Residual lignin agglutinating between the nanoparticles was observed in TEM image as well as in Fourier transform infrared (FTIR) spectra. The existence of residual lignin after hydrolysis is comparable in crystalinity (crystallinity index,Ic: ~91%) with that of isolated CNCs, as confirmed by x-ray diffraction (XRD) analysis.

scholarly journals Extraction and characterisation of cellulose nanocrystals (CNCs) from sugarcane bagasse using ionic liquids

2019 ◽  
Author(s):  
◽  
Gcinile Pretty Mdletshe
Keyword(s):  
Electron Microscopy ◽  
Ionic Liquids ◽  
Sugarcane Bagasse ◽  
Cellulose Nanocrystals ◽  
Crystallinity Index ◽  
Attenuated Total Reflection ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Pre Treatment

Lignocellulosic materials have the potential to partly replace fossil-based resources as a source of bio-fuels, bio-chemicals, bio-composites and other bio-products. In this study, ionic liquids (ILs) were used in the pre-treatment of ground sugarcane bagasse (SCB). The ILs used were 1-butyl-3-methylimidazolium hydrogen sulphate or 1-butyl-3-methylimidazolium methyl sulphate at varied times. The ILs were able to remove lignin and hemicellulose from biomass. The IL [bmim][HSO4] had the highest amount of lignin removed after 12 h than all samples. Moreover, it resulted in the greatest cellulose amount. Milled SCB was pre-treated with IL/dimethyl sulphoxide (DMSO) mixtures. The IL [bmim][HSO4] was able to produce cellulose nanocrystals (CNCs) at 90 % IL and 100 % IL. The other IL failed to produce CNCs. Freeze drying the CNC suspension showed morphologies of long fibrous structures and rods which were evident in the scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. The crystallinity index of cellulose in the form of CNCs was calculated from powder X-ray diffraction (P-XRD). Thermal analysis of the CNCs was obtained from thermogravimetric analysis (TGA). Attenuated total reflection-Fourier transform infrared (ATR-FTIR) was used to confirm the absence of lignin and hemicellulose in CNCs. The size distribution of CNCs was obtained by using a dynamic light scattering (DLS) which showed that all the CNCs for the 100 % IL [bmim][HSO4] pre-treatment had a length < 500 nm. It was found that [bmim][HSO4], with no DMSO, was the most effective in terms of cellulose dissolution and the crystal sizes of CNCs. The conversion of cellulose to CNCs was successful with a 80 % and 100 % conversion for 90 % [bmim][HSO4]/DMSO and 100 % [bmim][HSO4], respectively.

scholarly journals Valorization of underutilized river tamarind Leucaena leucocephala seeds biomass for cellulose nanocrystals synthesis

2021 ◽  
Vol 8 (1) ◽  
pp. 95-103
Author(s):  
Husin et al. ◽  
Keyword(s):  
Electron Microscopy ◽  
Cellulose Nanocrystals ◽  
Leucaena Leucocephala ◽  
Crystallinity Index ◽  
Gel Permeation Chromatography ◽  
Amorphous Region ◽  
Second Step ◽  
Gravimetric Analysis ◽  
Transmission Electron ◽  
The Fourier Transform

River tamarind or scientifically Leucaena leucocephala, is one of the underutilized nanocellulose resources with the potential to be used in reinforcement materials. This work evaluated the use of the insoluble residual waste or marc obtained during the isolation of galactomannan from Leucaena leucocephala seed (LLS) as a feedstock of cellulose to obtain cellulose nanocrystals by a two-step acid hydrolysis followed by its characterization and morphological study. The first step involved acid hydrolyzation of the hemicellulose and lignin from LLS, while the second step dealt with the removal of the amorphous region to produce crystalline LLS nanocrystals (NLLS). The physicochemical properties of nanocrystals were characterized using the Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), particle size analyzer (PSA), X-ray diffractometer (XRD), thermal gravimetric analysis (TGA), and gel permeation chromatography (GPC). The NLLS isolated showed a rod-like structure in the range of 70–90nm in diameter with a crystallinity index of 76% and thermal stability at 264°C. PSA indicates that 97.5% of the size distribution of NLLS was below 136.9nm. GPC analysis also revealed that the sulphuric acid hydrolyzation during the second step caused a reduction in the molecular weight due to the cleaving of glycosidic bonds in the structure. These results indicated that LLS waste is a potential feedstock for cellulose nanocrystals preparation.

scholarly journals Influence of Strong Acid Hydrolysis Processing on the Thermal Stability and Crystallinity of Cellulose Isolated from Wheat Straw

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Chemar J. Huntley ◽  
Kristy D. Crews ◽  
Mohamed A. Abdalla ◽  
Albert E. Russell ◽  
Michael L. Curry
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Scanning Electron Microscopy ◽  
Acid Hydrolysis ◽  
Wheat Straw ◽  
Cellulose Fibers ◽  
Drying Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Cellulose extractions from wheat straw via hydrochloric, nitric, and sulfuric acid hydrolysis methods were carried out. X-ray diffraction spectral analyses reveal that depending on the acid conditions used the structure of the cellulose exhibited a mixture of polymorphs (i.e., CI and CIII cellulose phases). In addition, the percent crystallinity, diameter, and length of the cellulose fibers varied tremendously as determined by X-ray diffraction and scanning electron microscopy. Thermal gravimetric analysis measurements revealed that the thermal stability of the extracted cellulose varied as a function of the acid strength and conditions used. Scanning electron microscopy analysis revealed that the aggregation of cellulose fibers during the drying process is strongly dependent upon the drying process and strength of the acids used.

Production of Cellulose Nanocrystals from Australian Wood Sources

2020 ◽  
Vol 20 (9) ◽  
pp. 5642-5647
Author(s):  
Lachlan Thompson ◽  
Mostafa Nikzad ◽  
Igor Sbarski ◽  
Jalal Azadmanjiri ◽  
Jiawen Ren ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
Acid Hydrolysis ◽  
Cellulose Nanocrystals ◽  
Chemical Treatment ◽  
Eucalyptus Globulus ◽  
Acacia Mangium ◽  
Kraft Pulps ◽  
High Yields

Two Australian native wooden sources (Acacia Mangium and Eucalyptus Globulus) derived pulps were explored as raw feed stocks to prepare the valuable nanomaterial of cellulose nanocrystals (CNC). After bleaching and acid hydrolysis, cellulose nanocrystals were successfully produced with high yields of approximately 60% for both kraft pulps. According to the characterization of SEM and AFM, the as prepared CNC had a rod like structure with the length and diameter in the range of 200~1000 nm and 10~100 nm, respectively based on the initial wooden source. XRD confirmed the crystalline structure of the resulting CNC. Further characterisation by TGA showed that the chemical treatment of the wood pulp had impact upon the thermal stability, evidenced by a lower onset temperature of the thermal decomposition of CNC.

scholarly journals Nanocrystalline Cellulose from Microcrystalline Cellulose of Date Palm Fibers as a Promising Candidate for Bio-Nanocomposites: Isolation and Characterization

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5313
Author(s):  
Amina Hachaichi ◽  
Benalia Kouini ◽  
Lau Kia Kian ◽  
Mohammad Asim ◽  
Hassan Fouad ◽  
...  
Keyword(s):  
Microcrystalline Cellulose ◽  
Food Packaging ◽  
Date Palm ◽  
Crystallinity Index ◽  
Nanocrystalline Cellulose ◽  
Crystalline Cellulose ◽  
Cellulose Content ◽  
Hydrolysis Time ◽  
Isolation And Characterization ◽  
Date Palm Fibers

Date palm fiber (Phoenix dactylifera L.) is a natural biopolymer rich in lignocellulosic components. Its high cellulose content lends them to the extraction of tiny particles like microcrystalline cellulose (MCC) and nanocrystalline cellulose (NCC). These cellulose-derived small size particles can be used as an alternative biomaterial in wide fields of application due to their renewability and sustainability. In the present work, NCC (A) and NCC (B) were isolated from date palm MCC at 60 min and 90 min hydrolysis times, respectively. The isolated NCC product was subjected to characterization to study their properties differences. With the hydrolysis treatment, the yields of produced NCC could be attained at between 22% and 25%. The infrared-ray functional analysis also revealed the isolated NCC possessed a highly exposed cellulose compartment with minimized lignoresidues of lignin and hemicellulose. From morphology evaluation, the nanoparticles’ size was decreased gradually from NCC (A) (7.51 nm width, 139.91 nm length) to NCC (B) (4.34 nm width, 111.51 nm length) as a result of fragmentation into cellulose fibrils. The crystallinity index was found increasing from NCC (A) to NCC (B). With 90 min hydrolysis time, NCC (B) showed the highest crystallinity index of 71% due to its great cellulose rigidity. For thermal analysis, NCC (B) also exhibited stable heat resistance, in associating with its highly crystalline cellulose structure. In conclusion, the NCC isolated from date palm MCC would be a promising biomaterial for various applications such as biomedical and food packaging applications.

scholarly journals Effects of Hybridized Organically Modified Montmorillonite and Cellulose Nanocrystals on Rheological Properties and Thermal Stability of K-Carrageenan Bio-Nanocomposite

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1547 ◽  
Author(s):  
Siti Zarina Zakuwan ◽  
Ishak Ahmad
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Cellulose Nanocrystals ◽  
Nanocomposite Films ◽  
Morphological Properties ◽  
Modified Montmorillonite ◽  
Organically Modified Montmorillonite ◽  
Organically Modified ◽  
The Matrix ◽  
Thermal Stability Of

Herein, hybrid k-carrageenan bio-nanocomposite films were fabricated by using two types of nanofillers, organically modified montmorillonite (OMMT), and cellulose nanocrystals (CNCs). Hybrid bio-nanocomposite films were made by casting techniques employing 4 wt% of CNCs, OMMT, and hybridized CNCs/OMMT in a 1:1 ratio. The rheological and morphological properties and thermal stability of all composites were investigated using rotational rheometry, thermogravimetry analysis, differential scanning calorimetry, field emission scanning electron microscopy, and transmission electron microscopy (TEM). The results showed that the hybrid CNC/OMMT bio-nanocomposite exhibited significantly improved properties as compared to those for the bio-nanocomposites with single fillers due to the nanosize and homogenous nanofiller dispersion in the matrix. Rheological analysis of the hybrid bio-nanocomposite showed higher dynamic shear storage modulus and complex viscosity values when compared to those for the bio-nanocomposite with individual fillers. The TEM analysis of the hybridized CNC/OMMT bio-nanocomposite revealed that more particles were packed together in the CNC network, which restricted the matrix mobility. The heat resistance and thermal stability bio-nanocomposite k-carrageenan film enhanced rapidly with the addition of hybridized CNCs/OMMT to 275 °C. The hybridized CNCs/OMMT exhibited synergistic effects due to the good affinity through interfacial interactions, resulting in the improvement of the material properties.

Thermal properties enhancement of poly(lactic acid) by corn cob cellulose nanocrystals

2019 ◽  
Vol 10 (4) ◽  
pp. 63-76
Author(s):  
Wei Keat Ng ◽  
Wen Shyang Chow ◽  
Hanafi Ismail
Keyword(s):  
Thermal Stability ◽  
Lactic Acid ◽  
Thermal Properties ◽  
Zeta Potential ◽  
Acid Hydrolysis ◽  
Cellulose Nanocrystals ◽  
Agricultural Waste ◽  
Poly Lactic Acid ◽  
Corn Cob ◽  
Thermal Stability Of

Cellulose nanocrystals were extracted from agricultural waste corn cob using acid hydrolysis followed by freeze drying. Poly(lactic acid)/corn cob cellulose nanocrystals (PLA/CCNC) composites were prepared using solvent casting. The properties of CCNC were characterized using transmission electron microscope (TEM), zeta potential analyzer, and thermogravimetric analyzer (TGA). The effects of CCNC on the thermal properties of PLA were examined using differential scanning calorimetry (DSC) and TGA. From the SEM and TEM results, the irregular shaped and micron-sized corn cob powder was transformed to needle-like shaped nanocellulose (aspect ratio approximately 30.80) after the acid hydrolysis process. TGA results show that the thermal stability of CCNC is higher than that of corn cob powder. The zeta potential of CCNC is −24.6 mV, which indicates there is a repulsion force between the individual CCNC and making them disperse uniformly and stable in aqueous media. DSC and TGA results show that the crystallinity and thermal stability of PLA were increased by the incorporation of CCNC. This demonstrates that the CCNC is a potential bio-nanofiller with good thermal stability and nucleating-ability for PLA.

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