scholarly journals N-acylhydrazone Derivative-Loaded Cellulose Acetate Films: Thermoanalytical, Spectroscopic, Mechanical and Morphological Characterization

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2345
Author(s):  
Amaro César Lima de Assis ◽  
Lívia Maria Coelho de Carvalho Moreira ◽  
Beatriz Patrício Rocha ◽  
Milena Raissa Bezerra Pereira ◽  
Demis Ferreira de Melo ◽  
...  
Keyword(s):  
Cellulose Acetate ◽  
Average Diameter ◽  
Morphological Characterization ◽  
Mechanical Tests ◽  
Spectroscopic Techniques ◽  
Cellulose Derivatives ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Synthetic Materials ◽  
Dsc Analyses

Cellulose acetate (ACT) is one of the most important cellulose derivatives due to its biodegradability and low toxicity, presenting itself as one of the main substitutes for synthetic materials in the development of wound dressing films. The incorporation of a N-acylhydrazonic derivative (JR19), with its promising anti-inflammatory activity, may represent an alternative for the treatment of skin wounds. This work aims to develop and to physicochemically and mechanically characterize ACT films containing JR19. The films were prepared using the ‘casting’ method and further characterized by thermoanalytical and spectroscopic techniques. In addition, mechanical tests and morphological analysis were performed. Thermogravimetry (TG) and differential scanning calorimetry (DSC) analyses showed that the thermal events attributed to excipients and films were similar, indicating the absence of physical incompatibilities between ACT and JR19. Infrared spectroscopy showed that JR19 was incorporated into ACT films. The characteristic band attributed to C≡N (2279 to 2264 cm−1) was observed in the spectra of JR19, in that of the physical mixture of JR19/ACT, and, to a lesser extent, in the spectra of JR19 incorporated into the ACT film, suggesting some interaction between JR19 and ACT. X-ray diffraction (XRD) evidenced the suppression of the crystallinity of JR19 (diffraction peaks at 8.54°, 12.80°, 14.09°, 16.08°, 18.19°, 22.65°, 23.59°, 24.53°, 25.70°, 28.16° and 30.27°2θ) after incorporation into ACT films. The mechanical tests indicated the adequate integrity of the films and their resistance to bending. The morphological characterization showed JR19 crystals along with a homogeneously distributed porous structure throughout the surface of the films with an average diameter of 21.34 µm and 22.65 µm of the films alone and of those incorporating JR19F, respectively. This study was able to characterize the ACT films incorporating JR19, showing their potential to be further developed as wound healing dressings.

Investigation on β-Polypropylene/Talc Composites

2012 ◽  
Vol 182-183 ◽  
pp. 259-264
Author(s):  
Jia Wei Duan ◽  
Qiang Dou
Keyword(s):  
Polarized Light ◽  
Nucleating Agent ◽  
Mechanical Tests ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Melt Compounding ◽  
Β Phase ◽  
Α Phase ◽  
Melting And Crystallization

In this study polypropylene (PP) composites containing β-nucleating agent (NT-C) and talc filler were prepared by melt compounding. The melting and crystallization behavior, morphology and mechanical properties of the composites were studied by means of differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD), polarized light microscopy (PLM) and mechanical tests. The results indicate that talc suppresses the formation of β phase, but promotes the formation of α phase. The Izod notched impact strength and tensile strength of β-PP/talc composites are superior to those of PP/talc composites, indicating an outstanding balance of stiffness and toughness of β-PP/talc composites.

scholarly journals Scientific Investigations of a 16th Century Stall Belonging to the Evangelic Church in Bistriţa, Bistriţa-Năsăud County, Romania

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
C. Marutoiu ◽  
S. P. Grapini ◽  
A. Baciu ◽  
M. Miclaus ◽  
V. C. Marutoiu ◽  
...  
Keyword(s):  
Back Side ◽  
Front Side ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Scientific Investigations ◽  
The Status ◽  
Dsc Analyses ◽  
The Church ◽  
Painting Layer

The Evangelic Church in Bistriţa city is one of the important gothic monuments in Romania. Inside the church there have been preserved a series of furniture pieces from different centuries, and the stall that has been analysed in this study is one of them. The study presents the investigations that were made on the occasion of restoring the stall. The nature and the status of the wooden supports and also the composition of the painting layer which covers the front side of the stall were investigated by several methods: Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and differential scanning calorimetry (DSC) analyses. The back side of the stall was made of spruce fir wood and its status was also investigated. The nature of the component elements and the heritage value of the ensemble were also established.

scholarly journals Use of sweet sorghum bagasse (Sorghum bicolor (L.) Moench) for cellulose acetate synthesis

BioResources ◽  
2019 ◽  
Vol 14 (2) ◽  
pp. 3534-3553
Author(s):  
José M. da Silva Neto ◽  
Líbia de S. C. Oliveira ◽  
Flávio L. H. da Silva ◽  
José N. Tabosa ◽  
José G. A. Pacheco ◽  
...  
Keyword(s):  
Cellulose Acetate ◽  
Cellulose Triacetate ◽  
Point Of View ◽  
Raw Material ◽  
Sodium Chlorite ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Sorghum Bagasse ◽  
Chemical Inputs ◽  
Sorghum Bicolor L

The objective of this work was to synthesize cellulose acetate from sorghum bagasse, a promising raw material for the production of chemical inputs, both from a photosynthetic point of view and the maturation speed compared with that of sugarcane. The bagasse was treated with hydrogen peroxide, and then cellulose was isolated using sodium chlorite, acetic acid, and sodium hydroxide. The cellulose was subjected to an acetylation reaction, from which cellulose triacetate was obtained. By means of statistical analysis, it was observed that the conditions that generated the highest solubilization of lignin (62%) and higher yield from cellulose extraction (39.5%) were 60 °C, a 6% peroxide concentration, and 4 h. Cellulose acetate was obtained with a degree of substitution of 3.66 at 25 °C and 24 h. Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetry, differential thermogravimetry, and differential scanning calorimetry analyses confirmed that the obtained cellulose presented specific characteristics of this material. Also, the reaction of acetylation was confirmed through these techniques.

scholarly journals Reinforcing polypropylene with calcium carbonate of different morphologies and polymorphs

2018 ◽  
Vol 25 (4) ◽  
pp. 745-751 ◽  
Author(s):  
Yanwei Jing ◽  
Xueying Nai ◽  
Li Dang ◽  
Donghai Zhu ◽  
Yabin Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Calcium Carbonate ◽  
Mechanical Tests ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Crystallization Property ◽  
Reinforced Composite ◽  
Treated Sample ◽  
The Impact

Abstract The influence of calcium carbonate (CaCO3) with different polymorphs (calcite and aragonite) and morphologies (granular and rod-like) on mechanical and crystallization properties of polypropylene (PP) was investigated. Meanwhile, these CaCO3 fillers coated with oleic acid were added in different contents to PP. The results indicate that the tensile strength, flexural strength, modulus, and crystallization property of the filler-treated samples are improved, but the impact strength decreased. The crystallinity of the composites is higher than that of neat PP. Moreover, in the rod shape filler-treated sample, in both whisker species, the mechanical properties of composites are superior to the particles filled. Differential scanning calorimetry, X-ray diffraction, and mechanical tests display that calcite whisker-reinforced composite has higher crystallization enthalpy, melting enthalpy, degree of crystallinity, and mechanical properties than aragonite whiskers and calcite particles filled composites.

scholarly journals Formulation and Characterization of gallic acid and quercetin chitosan nanoparticles for sustained release in treating Colorectal Cancer

2021 ◽  
Author(s):  
Poournima Patil ◽  
Suresh Killedar
Keyword(s):  
Colorectal Cancer ◽  
Gallic Acid ◽  
Chitosan Nanoparticles ◽  
Entrapment Efficiency ◽  
Aberrant Crypt Foci ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
Scanning Calorimetry

Abstract The current work was addressed to characterize gallic acid from amla fruit and quercetin from peels of pomegranate fruit and formulated into Chitosan (CS) nanoparticles and to evaluate their cytotoxicity towards human colorectal cancer (HCT 116) cell lines for the treatment of DMH induced colorectal cancer in Wistar rats. Identification of the biomolecules was performed by using different chromatographic and spectroscopic techniques, as 1H-NMR, GC-MS, LC-MS and HPTLC. Characterization of CS nanoparticles carried out by using X- ray diffraction (XRD) Differential scanning calorimetry (DSC), Scanning Electron Microscope (SEM), entrapment efficiency and In vitro drug release confirmed successful encapsulation of biomolecules into CS nanoparticles. A significant change in aberrant crypt foci (ACF) in CS nanoparticles compared to polyherbal extract were observed, with decrease in the colonic glutathione, catalase and superoxide dismutase levels and values differed significantly (P < 0.005).

scholarly journals Preparation of an Asymmetric Membrane from Sugarcane Bagasse Using DMSO as Green Solvent

2019 ◽  
Vol 9 (16) ◽  
pp. 3347 ◽  
Author(s):  
Nu ◽  
Hung ◽  
Hoang ◽  
Van der Bruggen
Keyword(s):  
Cellulose Acetate ◽  
Sugarcane Bagasse ◽  
Raw Material ◽  
Cellulose Derivatives ◽  
Asymmetric Membrane ◽  
Scanning Calorimetry ◽  
Water Contact ◽  
Force Microscopy ◽  
Cellulose Acetate Membranes ◽  
High Degree

Asymmetric cellulose acetate membranes have been successfully fabricated by phase inversion, using sugarcane bagasse (SB) as the starting material. SB is a raw material with high potential to produce cellulose derivatives due to its structure and morphology. Cellulose was extracted from SB by pretreatment with solutions of 5 wt% NaOH, 0.5 wt% EDTA; then bleached with 2 wt% H2O2. Cellulose acetate (CA) was prepared by the reaction between extracted cellulose with acetic anhydride, and H2SO4 as a catalyst. The obtained CA exhibited a high degree of substitution (2.81), determined with 1H-NMR spectroscopy and titration. The functional groups and thermal analysis of the extracted cellulose and the synthesized CA have been investigated by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The change in the crystallinity of the extracted cellulose and CA was evaluated by X-ray diffraction (XRD) spectroscopy. Asymmetric membranes were fabricated using dimethyl sulfoxide (DMSO) as the solvent, with a casting thickness of 250 µm. The obtained membranes were studied by scanning electron microscopy (SEM), DSC and atomic force microscopy (AFM). The hydrophilicity of the membranes was evaluated, as demonstrated by the measurement of water contact angle (WCA) and water content. Furthermore, the antifouling properties of membranes were also investigated.

Elastomeric Properties in Thermosetting Polymer Induced by Nanoclay Addition

2017 ◽  
Vol 894 ◽  
pp. 99-103
Author(s):  
Emee Grace T. Suarnaba ◽  
Ivy Ann C. Razonado ◽  
Lawrence V. Madriaga ◽  
Leslie Joy L. Diaz
Keyword(s):  
Network Formation ◽  
Polymer Network ◽  
Compressive Loading ◽  
Heat Of Reaction ◽  
X Ray Diffraction ◽  
Neat Resin ◽  
Scanning Calorimetry ◽  
Solution Intercalation ◽  
Transmission Electron ◽  
Dsc Analyses

This study focused on the effect of filler distribution and morphology on the observed mechanical behavior of nanocomposites under compressive loading. Polymer-clay nanocomposites (PCN) at various filler loadings were prepared via solution intercalation method. Organomodified montmorillonite (MMT) fillers were dispersed into nanometer length scales using high frequency ultrasonicator. Transmission electron microscopy (TEM) and x-ray diffraction (XRD) suggested polymer intercalation with a 44-52% increase in the d-spacing of MMT. Dynamic scanning calorimetry (DSC) analyses showed that the heat evolved during the curing process was relatively lower in PCN compared to the neat resin. This decrease in the magnitude of the heat of reaction (HR) was attributed to nanoclay addition. Since HR for a thermoset was primarily due to network formation, it was deduced that the crosslink density of neat resin is higher than that of PCN. Consequently, with fewer points of restriction in the polymer network, PCN has a higher propensity of sustaining larger elastic strain under low loadings. This behavior is similar to an elastomer despite the thermoset nature of the PCN.

Evaluation of the photostabilizing efficiency of polyvinyl alcohol–zinc chloride composites

2018 ◽  
Vol 33 (1) ◽  
pp. 69-84 ◽  
Author(s):  
Sameer A Awad ◽  
Eman M Khalaf
Keyword(s):  
Tensile Strength ◽  
Polyvinyl Alcohol ◽  
Storage Modulus ◽  
Zinc Chloride ◽  
Mechanical Analysis ◽  
Mechanical Tests ◽  
Accelerated Weathering ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Electron Microscopic

Accelerated weathering of polyvinyl alcohol (PVA) and PVA reinforced with 20 wt% of zinc chloride (ZnCl2) was investigated. The developed PVA composites were subjected to 100, 200, and 300 h of accelerated weathering exposure times. The effects of exposure on the PVA composites were characterized by Fourier transform infrared (FTIR), thermal properties as thermogravimetric analysis and differential scanning calorimetry, the mechanical and morphology properties, and X-ray diffraction analysis. The results of FTIR displayed that lower carbonyl and hydroxyl indexes are due to PVA composite. The results of mechanical tests showed that the accelerated weathering reduced the tensile strength of PVA. However, PVA composites exhibited fewer reduction of the tensile strength values. PVA composites exhibited better thermal stability after extent to ultraviolet irradiation. The storage modulus from dynamic mechanical analysis results that displayed a higher value for the storage modulus is related to PVA composites, compared to PVA. Before exposure, PVA composite showed a high intensity, compared to PVA. After exposure to accelerated weathering, the intensity of all samples shifted and decreased. Scanning electron microscopic micrographs showed that the surface of the PVA composites had fewer defects compared to the PVA after exposure. The results of characterization revealed that 20% of ZnCl2 into the PVA made less vulnerable to environmental degradation, and these PVA composites are suitable as packaging films for use in outdoor applications.

scholarly journals Fat Crystal Spheroids – Formation, Characterization, Structure Modification, and use as Encapsulation Matrices

2021 ◽  
Author(s):  
Tu Tran
Keyword(s):  
Shear Rate ◽  
Canola Oil ◽  
Critical Concentration ◽  
Polarized Light ◽  
Average Diameter ◽  
Shell Morphology ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Emulsion Droplets ◽  
Three Phase

Model fat systems consisting of fully-hydrogenated canola oil (FHCO) and canola oil (CO) were shear-crystallized using a rheometer with a parallel plate geometry at various cooling rates (0.2 to 5.0 ºC/min) and shear rates (0, 500, 1000, and 2000 s-1) to produce spheroidal fat crystals. These spheroids were characterized via rheology, polarized light microscopy (PLM), differential scanning calorimetry (DSC), and x-ray diffraction (XRD). Crystal spheroid formation was optimal at 1.0 ºC/min and viscosity profiles followed a three phase sigmoidal shape. PLM analysis revealed that spheroid size decreased with increased shear rate while sphericity increased. A multi-step mechanism was proposed for the formation of these crystal spheroids. Subsequently, different emulsifiers were used to modify the structure of these crystal spheroids and it was found that the type and concentration of emulsifier had significant effects on spheroid microstructure. Below a critical concentration, emulsifier could be incorporated into the crystal matrix of FHCO while above they would crystallize independently. DSC analysis revealed additional melting fractions compared to the control that were attributed to emulsifier incorporation and co-crystallization with FHCO. XRD showed that the crystallized spheroids were mainly of the βʹ polymorph regardless of the presence or type of emulsifier. A water phase was then introduced within these systems to study their encapsulation potential. Emulsifier type significantly affected crystal shell morphology and encapsulation efficacy. The liquid-state emulsifiers (GMO and PGPR) showed limited interaction with FHCO, with GMO delaying the interfacial crystallization of FHCO while PGPR excluded FHCO from the droplet interface completely. Of the solid-state emulsifiers (GMS, GMP, SMS, and STS), the MAGs produced smooth-surfaced crystal shells around the emulsion droplets while the sorbitan-based emulsifiers produced irregularly-shaped shells and droplet cores (SMS) or incomplete crystal shell formation (STS). The shear-crystallization of our model fat blend also resulted in the formation of cylindrical crystalline assemblies. The average diameter size of these crystal cylinders decreased with increased shear rate. A “log-rolling” mechanism was proposed for their formation. These results demonstrate that laminar shear may be used to modify fat crystal microstructure and induce the formation of spheroidal and cylindrical crystalline assemblies.

scholarly journals Electrospun Polycaprolactone Fibrous Membranes Containing Ag, TiO2 and Na2Ti6O13 Particles for Potential Use in Bone Regeneration

Membranes ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 12 ◽  
Author(s):  
Erick Ramírez-Cedillo ◽  
Wendy Ortega-Lara ◽  
María Rocha-Pizaña ◽  
Janet Gutierrez-Uribe ◽  
Alex Elías-Zúñiga ◽  
...  
Keyword(s):  
Antibacterial Properties ◽  
Average Diameter ◽  
Biological Properties ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Electrospun Membranes ◽  
Base Polymer ◽  
Fibrous Membranes ◽  
Nih 3T3

Biocompatible and biodegradable membrane treatments for regeneration of bone are nowadays a promising solution in the medical field. Bioresorbable polymers are extensively used in membrane elaboration, where polycaprolactone (PCL) is used as base polymer. The goal of this work was to improve electrospun membranes’ biocompatibility and antibacterial properties by adding micro- and nanoparticles such as Ag, TiO2 and Na2Ti6O13. Micro/nanofiber morphologies of the obtained membranes were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, differential scanning calorimetry, scanning electron microscopy, energy-dispersive X-ray spectroscopy and a tensile test. Also, for this study optical microscopy was used to observe DAPI-stained cells. Membranes of the different systems were electrospun to an average diameter of 1.02–1.76 μm. To evaluate the biological properties, cell viability was studied by growing NIH/3T3 cells on the microfibers. PCL/TiO2 strength was enhanced from 0.6 MPa to 6.3 MPa in comparison with PCL without particles. Antibacterial activity was observed in PCL/TiO2 and PCL/Na2Ti6O13 electrospun membranes using Staphylococcus aureus bacteria. Bioactivity of the membranes was confirmed with simulated body fluid (SBF) treatment. From this study, the ceramic particles TiO2 and Na2Ti6O13, combined with a PCL matrix with micro/nanoparticles, enhanced cell proliferation, adhesion and antibacterial properties. The electrospun composite with Na2Ti6O13 can be considered viable for tissue regenerative processes.

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