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 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 Isolation and Characterization of Alpha and Nanocrystalline Cellulose from Date Palm (Phoenix dactylifera L.) Trunk Mesh

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1893
Author(s):  
Hamid M. Shaikh ◽  
Arfat Anis ◽  
Anesh Manjaly Poulose ◽  
Saeed M. Al-Zahrani ◽  
Niyaz Ahamad Madhar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Date Palm ◽  
Microscopic Analysis ◽  
Nanocrystalline Cellulose ◽  
Attenuated Total Reflection ◽  
Waste Biomass ◽  
Structure Property ◽  
Scanning Calorimetry ◽  
Good Thermal Stability ◽  
Isolation And Characterization

Highly pure cellulosic polymers obtained from waste lignocellulose offer great potential for designing novel materials in the concept of biorefinery. In this work, alpha-cellulose and nanocrystalline cellulose were isolated from the date palm trunk mesh (DPTM) through a series of physicochemical treatments. Supercritical carbon dioxide treatment was used to remove soluble extractives, and concentrated alkali pretreatment was used to eliminate the lignin portion selectively to obtain alpha-cellulose in approximately 94% yield. Further treatments of this cellulose yielded nanocrystalline cellulose. The structure–property relationship studies were carried out by characterizing the obtained polymers by various standard methods and analytical techniques such as Fourier transform infrared spectroscopy-attenuated total reflection (FTIR-ATR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), energy dispersive X-ray diffraction (EDX-XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Almost 65% yield of pure cellulose was achieved, out of which 94% is the alpha-cellulose. This cellulose shows good thermal stability and crystallinity. The microscopic analysis of the nanocellulose showed a heterogeneous mix of irregular-shaped particles with a size range of 20–60 nm. The percentage crystallinity of alpha-cellulose and nanocellulose was found to be 68.9 and 71.8, respectively. Thus, this study shows that, this DPTM-based low-cost waste biomass can be a potential source to obtain cellulose and nano-cellulose.

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 Cellulose Nanocrystals Obtained From Microcrystalline Cellulose by p-toluene Sulfonic Acid Hydrolysis, NaOH and Ethylenediamine Treatment

2021 ◽  
Author(s):  
Songlin Wang ◽  
Qian Wang ◽  
Yao Kai
Keyword(s):  
Microcrystalline Cellulose ◽  
Cellulose Nanocrystals ◽  
Sulfonic Acid ◽  
Crystallinity Index ◽  
X Ray Diffraction ◽  
Cellulose I ◽  
Good Thermal Stability ◽  
Transmission Electron ◽  
Toluene Sulfonic Acid ◽  
Comprehensive Characterization

Abstract Cellulose nanocrystals (CNC) were first isolated from microcrystalline cellulose (MCC) by p-toluene sulfonic acid (p-TsOH) hydrolysis. Cellulose II nanocrystal (CNC II) and cellulose III nanocrystal (CNC III) were then formed by swelling the obtained cellulose I nanocrystal (CNC I) in concentrated sodium hydroxide solutions and ethylenediamine (EDA) respectively. The properties of CNC I, CNC II and CNC III were subjected to comprehensive characterization by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The results indicated that CNC I, CNC II and CNC III obtained in this research had high crystallinity index and good thermal stability. The degradation temperatures of the resulted CNC I, CNC II and CNC III were 300 ℃, 275 ℃ and 242 ℃, respectively. No ester bonds were found in the resulted CNC. CNC prepared in this research also had large aspect ratio and high negative zeta potential.

Mechanical and Thermomechanical Properties of Nylon6T/66/PPS Blends

2015 ◽  
Vol 815 ◽  
pp. 503-508
Author(s):  
Qi Zhang ◽  
Xiao Lin Luo ◽  
Mei Lin Zhang ◽  
Xiao Jun Wang ◽  
Gang Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Flexural Modulus ◽  
Thermomechanical Properties ◽  
Polymer Materials ◽  
Scanning Calorimetry ◽  
Polymer Blending ◽  
Good Thermal Stability ◽  
Aromatic Polyamides ◽  
Scanning Electron ◽  
Better Than

Polymer blending is a very important and widely used method for the modification of polymer materials. However, little attention has been paid to the Semi-aromatic Polyamides with PPS blends. In this article, we investigate the properties of Poly (phenylene sulfide) (PPS) blends with Poly (hexamethylene terephthalamide/hexamethylene hexanediamide) (nylon 6T/66). The structure, mechanical properties of nylon 6T/66 and (PPS) blends were studied by scanning electron microscopy (SEM), Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TG). The results indicate that the blends have good thermal stability and the tensile strength, flexural strength and flexural modulus of the blends are better than the PA6T/66 but worse than that of the PPS.

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 Fabrication and characterization of novel multilayered structures by stereocomplexion of poly(D-lactic acid)/poly(L-lactic acid) and self-assembly of polyelectrolytes

2016 ◽  
Vol 7 ◽  
pp. 81-90 ◽  
Author(s):  
Elena Dellacasa ◽  
Li Zhao ◽  
Gesheng Yang ◽  
Laura Pastorino ◽  
Gleb B Sukhorukov
Keyword(s):  
Electron Microscopy ◽  
Lactic Acid ◽  
Chemical Composition ◽  
Drug Carrier ◽  
Single Layer ◽  
Attenuated Total Reflection ◽  
Poly Lactic Acid ◽  
Layer By Layer ◽  
Multilayered Structures ◽  
Scanning Calorimetry

The enantiomers poly(D-lactic acid) (PDLA) and poly(L-lactic acid) (PLLA) were alternately adsorbed directly on calcium carbonate (CaCO3) templates and on poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) multilayer precursors in order to fabricate a novel layer-by-layer (LBL) assembly. A single layer of poly(L-lysine) (PLL) was used as a linker between the (PDLA/PLLA) n stereocomplex and the cores with and without the polymeric (PSS/PAH) n /PLL multilayer precursor (PEM). Nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC) were used to characterize the chemical composition and molecular weight of poly(lactic acid) polymers. Both multilayer structures, with and without polymeric precursor, were firstly fabricated and characterized on planar supports. A quartz crystal microbalance (QCM), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and ellipsometry were used to evaluate the thickness and mass of the multilayers. Then, hollow, spherical microcapsules were obtained by the removal of the CaCO3 sacrificial template. The chemical composition of the obtained microcapsules was confirmed by differential scanning calorimetry (DSC) and wide X-ray diffraction (WXRD) analyses. The microcapsule morphology was evaluated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) measurements. The experimental results confirm the successful fabrication of this innovative system, and its full biocompatibility makes it worthy of further characterization as a promising drug carrier for sustained release.

scholarly journals Characterization of Cellulose Nanocrystals Derived from Umbrella Plant (Cyperus alternifolius Linn.)

2020 ◽  
pp. 33-42
Author(s):  
Marcelino R. Tradio Jr. ◽  
Brian John Sarno
Keyword(s):  
Electron Microscopy ◽  
Cellulose Nanocrystals ◽  
Crystallinity Index ◽  
Crystalline Cellulose ◽  
Transmission Electron ◽  
Thermal Analyzer ◽  
Decomposition Behavior ◽  
Xrd Patterns ◽  
Index Value ◽  
20 Nm

Plant–based nanocrystals have gained wide research interest due to its application in nano–reinforcement. Hence, the study investigated the stems of umbrella plant as potentials source of cellulose fibers to synthesize cellulose nanocrystals (CNCs). The synthesis of CNCs were conducted using acid hydrolysis with 10 mL 64% w/w sulfuric acid for each gram of purified cellulose at 45°C for 30 min. The surface morphology, structural, physical and thermal properties of CNCs were characterized using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier Transform Infrared spectroscopy (FTIR), X–ray diffractometer (XRD), and simultaneous thermal analyzer, respectively. The result showed that the CNCs were mixture of rod–like shape and spherical morphology. The CNC rods were less than 20 nm width and 200–300 nm length when viewed under FESEM. However, the CNC rods were shorter when viewed under TEM and had a width less than 5 nm and length between 20–50 nm. The spherical CNCs that were seen only under TEM were less than 20 nm in diameter. The FTIR spectra showed that the CNCs were composed of crystalline cellulose I wherein the molecular structure of cellulose was preserved after the hydrolysis. The XRD patterns showed that the CNCs were highly crystalline with crystallinity index value of 94.48%. Lastly, the CNCs exhibited a three–stage thermal decomposition behavior.

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.

Electron microscopy of crystalline structure in thermotropic random copolymers

1991 ◽  
Vol 49 ◽  
pp. 1054-1055
Author(s):  
Afzana Anwer ◽  
S. Eilidh Bedford ◽  
Richard J. Spontak ◽  
Alan H. Windle
Keyword(s):  
Electron Microscopy ◽  
Crystalline Structure ◽  
Liquid Crystalline ◽  
Elevated Temperatures ◽  
Random Copolymers ◽  
Molecular Characteristics ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Identical Monomer ◽  
Periodic Layer

Random copolyesters composed of wholly aromatic monomers such as p-oxybenzoate (B) and 2,6-oxynaphthoate (N) are known to exhibit liquid crystalline characteristics at elevated temperatures and over a broad composition range. Previous studies employing techniques such as X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) have conclusively proven that these thermotropic copolymers can possess a significant crystalline fraction, depending on molecular characteristics and processing history, despite the fact that the copolymer chains possess random intramolecular sequencing. Consequently, the nature of the crystalline structure that develops when these materials are processed in their mesophases and subsequently annealed has recently received considerable attention. A model that has been consistent with all experimental observations involves the Non-Periodic Layer (NPL) crystallite, which occurs when identical monomer sequences enter into register between adjacent chains. The objective of this work is to employ electron microscopy to identify and characterize these crystallites.

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