scholarly journals Extraction of Microfibrillar Cellulose From Waste Paper by NaOH/Urethane Aqueous System and Its Utility in Removal of Lead from Contaminated Water

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2850
Author(s):  
Vadahanambi Sridhar ◽  
Hyun Park
Keyword(s):  
Electron Microscopy ◽  
Xrd Analysis ◽  
Aqueous System ◽  
Microfibrillated Cellulose ◽  
Waste Paper ◽  
Contaminated Water ◽  
Waste Biomass ◽  
Scanning Calorimetry ◽  
Cellulose Fibrils ◽  
Microfibrillar Cellulose

Though recycling of waste paper is widely practiced but usually it is downgraded to lower valued recycled waste paper. Based on this concern, we report the development of novel NaOH/urethane aqueous system for extraction of microfibrillated cellulose from waste paper. The purity of so obtained microfibrillated cellulose (MFC) was evaluated by morphological tests using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and by evaluation of physicochemical properties using Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Morphologies of MFC studied by SEM and TEM showed that the size of purified cellulose fibrils reduced when compared to that of waste paper but fibrils are cleaner and smoother due to the removal of talc and lignin. XRD analysis revealed that MFC exhibits good crystallinity. The utility of sulfonated and pristine microfibrillar cellulose in removal of lead from contaminated water is also reported. Our results show that renewable, sustainable, cheap, and waste biomass like waste paper can be used for producing valuable second-generation high-value products.

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 Multicenter project Brazil-Italy: physicochemical analysis of Zincum metallicum and lactose in dynamized mixtures

2021 ◽  
Vol 15 (4) ◽  
pp. 41-42
Author(s):  
Carla Holandino ◽  
Adriana Passos Oliveira ◽  
Fortune Homsani ◽  
Thaís Fernandes ◽  
Michelle Rodrigues de Lima Zanetti ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Statistical Significance ◽  
Amorphous State ◽  
Xrd Analysis ◽  
Physicochemical Analysis ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Mean Size

Background: The use of sensitive techniques can be useful to increase the understanding of homeopathic systems behavior. Aim: To analyze physicochemical properties of Zincum metallicum and lactose mixtures prepared according to Brazilian Homeopathic Pharmacopeia. Methodology: Zincum metallicum was prepared using lactose as vehicle, from 1 to 3 cH, and from 1 to 6dH. All samples including respective controls (dynamized lactose) were analyzed by Atomic Absorption Spectroscopy (AAS), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) with X-Ray Energy Dispersive Spectroscopy (EDX), Scanning Electron Microscopy (SEM), and Differential Scanning Calorimetry (DSC). Results: AAS analysis showed the dynamization process decreases zinc concentration in a proportional manner to the increase of homeopathic potencies. Quantities of 4ppm and 132 ppm of zinc were detected in 6dH and 3cH, respectively. XRD analysis showed crystalline form of lactose was not modified by dynamization. Amorphous lactose spheres were observed by TEM in all samples, with mean size ranging from 800 to 200 nm. EDX obtained in the TEM confirmed zinc presence throughout the amorphous matter and the absence of individualized zinc crystalline particles. These results are in accordance with XRD which showed absence of zinc diffraction peaks, in all lactose samples containing zinc suggesting this metal could be modified from crystalline to amorphous state, and consequently adsorbed into lactose molecules. SEM structural analysis of lactose and zinc (1cH) samples using BSE detector showed no zinc metal grains confirming XRD and TEM results. DSC analyses presented statistical significance differences (p

scholarly journals Studies on PEBAX/organoclay nanocomposites by meltintercalation process: Effect of organoclay surface

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Somayeh Mohamadi ◽  
Naser Sharifi Sanjani
Keyword(s):  
Electron Microscopy ◽  
Tensile Modulus ◽  
Melt Flow Index ◽  
Xrd Analysis ◽  
Flow Index ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Transition Electron Microscopy ◽  
Clay Concentration ◽  
Alkyl Ammonium

AbstractIn this study, the polyetherblock amide (PEBAX)® nanocomposites with 2.5 % and 5 wt.% organoclay, based on Cloisite 30B (montmorillonite intercalated with dimethyl, 2-ethyl hexyl hydrogenated tallow alkyl ammonium cation), were prepared by the melt-intercalation process. The structural properties, thermal behaviors and the mechanical properties were characterized using the X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), melt flow index (MFI), differential scanning calorimetry (DSC), thermogravimetry analyses (TGA), transition electron microscopy (TEM), scanning electron microscopy (SEM) and the tensile test. The XRD analysis indicated the formation of intercalated PEBAX nanocomposites. The TGA results revealed that the addition of 2.5 wt.% nanoclay improved the thermal properties, while the nanocomposite with 5 wt.% nanoclay did not enhance the thermal stability. The DSC analysis indicated that, in the case of PEBAX with 2.5 wt.% organoclay, each peak was related to the fusion of the crystalline fraction of the poly ether and poly amide affected blocks. On the contrary, regarding the PEBAX with 5 wt.% nanoclay, only the peak related to polyamide was changed. Interestingly, the tensile modulus increased with the incorporation of 2.5 wt.% clay, but it decreased in PEBA 5. The elongation at break reduced with the incorporation of the clay, attaining a minimum value at the clay concentration of 2.5 wt.%, and followed by an increase at the clay concentration of 5 wt.%.

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.

Light-cured dental composites characterization by Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 428-429
Author(s):  
B. M. Culbertson ◽  
M. L. Devinev ◽  
E. C. Kao
Keyword(s):  
Electron Microscopy ◽  
Mechanical Analysis ◽  
Service Performance ◽  
Dental Composite ◽  
Dental Composites ◽  
Neat Resin ◽  
Scanning Calorimetry ◽  
Research Meeting ◽  
Formulation Variables

The service performance of current dental composite materials, such as anterior and posterior restoratives and/or veneer cements, needs to be improved. As part of a comprehensive effort to find ways to improve such materials, we have launched a broad spectrum study of the physicochemical and mechanical properties of photopolymerizable or visible light cured (VLC) dental composites. The commercially available VLC materials being studied are shown in Table 1. A generic or neat resin VLC system is also being characterized by SEM and TEM, to more fully understand formulation variables and their effects on properties.At a recent dental research meeting, we reported on the differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) characterization of the materials in Table 1. It was shown by DSC and DMA that the materials are substantially undercured by commonly used VLC techniques. Post curing in an oral cavity or a dry environment at 37 to 50°C for 7 or more hours substantially enhances the cure of the materials.

Electron microscopy and diffraction of crystalline dendrimers and macrocycles

1993 ◽  
Vol 51 ◽  
pp. 1218-1219
Author(s):  
C. J. Buchko ◽  
P. M. Wilson ◽  
Z. Xu ◽  
J. Zhang ◽  
S. Lee ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Liquid Crystalline ◽  
Structural Information ◽  
High Resolution Electron Microscopy ◽  
Scanning Calorimetry ◽  
Tertiary Butyl ◽  
Phenyl Acetylene ◽  
Selected Area Electron Diffraction ◽  
Liquid Crystalline Phases ◽  
Resolution Electron

The synthesis of well-defined organic molecules with unique geometries opens new opportunities for understanding and controlling the organization of condensed matter. Here, we study dendrimers and macrocycles which are synthesized from rigid phenyl-acetylene spacer units, Both units are solubilized by the presence of tertiary butyl groups located at the periphery of the molecule. These hydrocarbon materials form crystalline and liquid crystalline phases which have been studied by differential scanning calorimetry, hot stage optical microscopy, and wide-angle x-ray scattering (WAXS).The precisely defined architecture of these molecules makes it possible to investigate systematic variations in chemical architecture on the nature of microstructural organization. Here we report on the transmission electron microscopy (TEM), selected area electron diffraction (SAED), and high resolution electron microscopy (HREM) studies of crystalline thin films formed by deposition of these materials onto carbon substrates from dilute solution. Electron microscopy is very attractive for gaining structural information on new molecules due to the scarcity of material to grow single crystals suitable for conventional crystallography.

Mannose Conjugated Starch Nanoparticles for Preferential Targeting of Liver Cancer

2020 ◽  
Vol 17 ◽  
Author(s):  
Akhlesh Kumar Jain ◽  
Hitesh Sahu ◽  
Keerti Mishra ◽  
Suresh Thareja
Keyword(s):  
Side Effects ◽  
Liver Cancer ◽  
Entrapment Efficiency ◽  
Xrd Analysis ◽  
In Vitro Cytotoxicity ◽  
Physical Interaction ◽  
Scanning Calorimetry ◽  
Starch Nanoparticles

Aim: To design D-Mannose conjugated 5-Fluorouracil (5-FU) loaded Jackfruit seed starch nanoparticles (JFSSNPs) for site specific delivery. Background: Liver cancer is the third leading cause of death in world and fifth most often diagnosed cancer is the major global threat to public health. Treatment of liver cancer with conventional method bears several side effects, thus to undertake these side effects as a formulation challenge, it is necessary to develop novel target specific drug delivery system for the effective and better localization of drug into the proximity of target with restricting the movement of drug in normal tissues. Objective: To optimize and characterize the developed D-Mannose conjugated 5-Fluorouracil (5-FU) loaded Jackfruit seed starch nanoparticles (JFSSNPs) for effective treatment of liver cancer. Materials and methods: 5-FU loaded JFSSNPs were prepared and optimized formulation had higher encapsulation efficiency were conjugated with D-Mannose. These formulations were characterized for size, morphology, zeta potential, X-Ray Diffraction, and Differential Scanning Calorimetry. Potential of NPs were studied using in vitro cytotoxicity assay, in vivo kinetic studies and bio-distribution studies. Result and discussion: 5-Fluorouracil loaded NPs had particle size between 336 to 802nm with drug entrapment efficiency was between 64.2 to 82.3%. In XRD analysis, 5-FU peak was diminished in the diffractogram, which could be attributed to the successful incorporation of drug in amorphous form. DSC study suggests there was no physical interaction between 5- FU and Polymer. NPs showed sustained in vitro 5-FU release up to 2 hours. In vivo, mannose conjugated NPs prolonged the plasma level of 5-FU and assist selective accumulation of 5-FU in the liver (vs other organs spleen, kidney, lungs and heart) compared to unconjugated one and plain drug. Conclusion: In vivo, bio-distribution and plasma profile studies resulted in significantly higher concentration of 5- Fluorouracil liver suggesting that these carriers are efficient, viable, and targeted carrier of 5-FU treatment of liver cancer.

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 Study on Structure, Thermal Behavior, and Viscoelastic Properties of Nanodiamond-Reinforced Poly (vinyl alcohol) Nanocomposites

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1426
Author(s):  
Tomáš Remiš ◽  
Petr Bělský ◽  
Tomáš Kovářík ◽  
Jaroslav Kadlec ◽  
Mina Ghafouri Azar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Analysis ◽  
Single Step ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Primary Particles ◽  
Solution Casting Method ◽  
Average Size

In this work, advanced polymer nanocomposites comprising of polyvinyl alcohol (PVA) and nanodiamonds (NDs) were developed using a single-step solution-casting method. The properties of the prepared PVA/NDs nanocomposites were investigated using Raman spectroscopy, small- and wide-angle X-ray scattering (SAXS/WAXS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). It was revealed that the tensile strength improved dramatically with increasing ND content in the PVA matrix, suggesting a strong interaction between the NDs and the PVA. SEM, TEM, and SAXS showed that NDs were present in the form of agglomerates with an average size of ~60 nm with primary particles of diameter ~5 nm. These results showed that NDs could act as a good nanofiller for PVA in terms of improving its stability and mechanical properties.

scholarly journals Characteristics of Reconstituted Collagen Fibers from Chicken Keel Cartilage Depends on Salt Type for Removal of Proteoglycans

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3538
Author(s):  
Anna Pudło ◽  
Szymon Juchniewicz ◽  
Wiesław Kopeć
Keyword(s):  
Electron Microscopy ◽  
Rheological Properties ◽  
Thermal Denaturation ◽  
Surface Structures ◽  
Scanning Calorimetry ◽  
Cartilage Extracellular Matrix ◽  
Oscillatory Rheometry ◽  
Freeze Dried ◽  
Basic Features ◽  
Scanning Electron

The aim of the presented research was to obtain reconstituted atelocollagen fibers after extraction from poultry cartilage using the pepsin-acidic method in order to remove telopeptides from the tropocollagen. Firstly, we examined the extraction of collagen from the cartilage extracellular matrix (ECM) after proteoglycans (PG) had been removed by the action of salts, i.e., NaCl or chaotropic MgCl2. Additionally, the effects of the salt type used for PG and hyaluronic acid removal on the properties of self-assembled fibers in solutions at pH 7.4 and freeze-dried matrices were investigated. The basic features of the obtained fibers were characterized, including thermal properties using scanning calorimetry, rheological properties using dynamic oscillatory rheometry, and the structure by scanning electron microscopy. The fibers obtained after PG removal with both analyzed types of salts had similar thermal denaturation characteristics. However, the fibers after PG removal with NaCl, in contrast to those obtained after MgCl2 treatment, showed different rheological properties during gelatinization and smaller diameter size. Moreover, the degree of fibrillogenesis of collagens after NaCl treatment was complete compared to that with MgCl2, which was only partial (70%). The structures of fibers after lyophilization were fundamentally different. The matrices obtained after NaCl pretreatment form regular scaffolds in contrast to the thin, surface structures of the cartilage matrix after proteoglycans removal using MgCl2.

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