Copolymer of natural fibre reinforced polyester urethane: effect on physico-chemical properties through modification to interfacial adhesion

2016 ◽  
Vol 36 (2) ◽  
pp. 189-197
Author(s):  
Gabriela Jandikova ◽  
Pavel Kucharczyk ◽  
Norbert Miskolczi ◽  
Alena Pavelkova ◽  
Adriana Kovalcik ◽  
...  
Keyword(s):  
Interfacial Adhesion ◽  
Alkali Treatment ◽  
Chemical Properties ◽  
Gel Permeation Chromatography ◽  
Natural Fibre ◽  
Special Focus ◽  
Scanning Calorimetry ◽  
Polyester Urethane ◽  
Flax Fibres ◽  
Physico Chemical

Abstract This work is dedicated to polyester urethane (PEU)-based biocomposites, with special focus placed on techniques for compatibilisation to heighten interfacial adhesion between the PEU matrix and flax fibres. Tests were conducted on the effects of modification so as to increase interfacial adhesion between the flax fibres and the polyester matrix. These tests involved a commercial silane-based compatibilising additive, two experimentally synthesised agents, oleic acid (OA) and di-tert-butyl peroxide (DTBP). Furthermore, the flax fibres underwent acid or alkali treatment. The biocomposites were characterised by gel permeation chromatography, infrared spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). Mechanical properties were investigated through tensile testing. Biocomposites with a commercial silane-based additive and synthesised agent, based on maleic-anhydride, were assessed as the best solution. Nevertheless, all modifications, excluding alkali treatment of fibres, significantly increased the performance of the material.

scholarly journals Radiation-induced Grafting of Styrene onto Polyethylene Films for Preparation of Cation Exchange Membranes: Effect of Crosslinking+

2017 ◽  
Vol 2 (1) ◽  
Author(s):  
M. M. Nasef ◽  
H. Saidi ◽  
A. H. Yahaya
Keyword(s):  
Cation Exchange ◽  
Chemical Properties ◽  
Exchange Capacity ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Swelling Properties ◽  
Ion Exchange Capacity ◽  
Physico Chemical ◽  
Styrene Divinylbenzene ◽  
Radiation Induced

Crosslinked cation exchange membranes bearing sulfonic acid groups (PE-g-PSSA/DVB) were prepared by radiationinduced grafting of styrene/divinylbenzene (DVB) mixtures onto low density polyethylene (PE) films followed by sulfonation reactions. The effect of addition of DVB (2 and 4%) on the grafting behavior and the physico-chemical properties of the membranes such as ion exchange capacity, swelling and ionic conductivity were evaluated incorrelation with grafting yield (Y%). The structural and thermal properties of the membranes were also studied using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), respectively. Crosslinking with DVB was found to considerably affect the properties of the membranes in a way that reduces the swelling properties and enhances the chemical stability. The ion conductivity of the crosslinked membranes recorded a level of 10–2 S/cm at sufficient grafting yield (28%) despite the reduction caused by the formation of crosslinking structure. The results of this work suggest that membranes prepared in this study are potential alternatives for various electrochemical applications.

scholarly journals Eudragit S100 Entrapped Liposome for Curcumin Delivery: Anti-Oxidative Effect in Caco-2 Cells

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 114 ◽  
Author(s):  
Vincenzo De Leo ◽  
Sante Di Gioia ◽  
Francesco Milano ◽  
Paola Fini ◽  
Roberto Comparelli ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Polymeric Coating ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Physico Chemical ◽  
Eudragit S100 ◽  
Natural Polyphenol ◽  
Anti Oxidant ◽  
Small Unilamellar Vesicles

Curcumin is a natural polyphenol with strong antioxidant activity. However, this molecule shows a very poor bioavailability, instability, and rapid metabolism in vivo. In this work curcumin was loaded in Eudragit-coated liposomes to create a gastroresistant carrier, able to protect its load from degradation and free it at the site of absorption in the colon region. Small unilamellar vesicles were prepared and coated with Eudragit by a pH-driven method. The physico-chemical properties of the prepared systems were assessed by light scattering, transmission electron microscopy, infrared spectroscopy, and differential scanning calorimetry. The uptake of vesicles by Caco-2 cells and the anti-oxidant activity in cells were evaluated. The produced vesicles showed dimensions of about forty nanometers that after covering with Eudragit resulted to have micrometric dimensions at acid pH. The experiments showed that at pH > 7.0 the polymeric coating dissolves, releasing the nanometric liposomes and allowing them to enter Caco-2 cells. Delivered curcumin loaded vesicles were then able to decrease significantly ROS levels as induced by H2O2 in Caco-2 cells. The proposed work showed the possibility of realizing effective gastroresistant curcumin liposome formulations for the delivery of antioxidant molecules to Caco-2 cells, potentially applicable to the treatment of pathological conditions related to intestinal oxidative stress.

scholarly journals Technologies and Formulation Design of Polysaccharide-Based Hydrogels for Drug Delivery

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3156 ◽  
Author(s):  
Giulia Auriemma ◽  
Paola Russo ◽  
Pasquale Del Gaudio ◽  
Carlos A. García-González ◽  
Mariana Landín ◽  
...  
Keyword(s):  
Sol Gel ◽  
Chemical Properties ◽  
Drying Methods ◽  
Special Focus ◽  
Porous Network ◽  
Hydrogel Particles ◽  
Physico Chemical ◽  
Droplet Production ◽  
Inflammatory Drugs ◽  
Sol Gel Transition

Polysaccharide-based hydrogel particles (PbHPs) are very promising carriers aiming to control and target the release of drugs with different physico-chemical properties. Such delivery systems can offer benefits through the proper encapsulation of many drugs (non-steroidal and steroidal anti-inflammatory drugs, antibiotics, etc) ensuring their proper release and targeting. This review discusses the different phases involved in the production of PbHPs in pharmaceutical technology, such as droplet formation (SOL phase), sol-gel transition of the droplets (GEL phase) and drying, as well as the different methods available for droplet production with a special focus on prilling technique. In addition, an overview of the various droplet gelation methods with particular emphasis on ionic cross-linking of several polysaccharides enabling the formation of particles with inner highly porous network or nanofibrillar structure is given. Moreover, a detailed survey of the different inner texture, in xerogels, cryogels or aerogels, each with specific arrangement and properties, which can be obtained with different drying methods, is presented. Various case studies are reported to highlight the most appropriate application of such systems in pharmaceutical field. We also describe the challenges to be faced for the breakthrough towards clinic studies and, finally, the market, focusing on the useful approach of safety-by-design (SbD).

scholarly journals Titanium Dioxide (TiO2) Mesocrystals: Synthesis, Growth Mechanisms and Photocatalytic Properties

Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 91 ◽  
Author(s):  
Boxue Zhang ◽  
Shengxin Cao ◽  
Meiqi Du ◽  
Xiaozhou Ye ◽  
Yun Wang ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Building Blocks ◽  
High Specific Surface Area ◽  
Future Research ◽  
Special Focus ◽  
Growth Mechanisms ◽  
Environmental Deterioration ◽  
Physico Chemical ◽  
Potential Applications ◽  
Shed Light

Hierarchical TiO2 superstructures with desired architectures and intriguing physico-chemical properties are considered to be one of the most promising candidates for solving the serious issues related to global energy exhaustion as well as environmental deterioration via the well-known photocatalytic process. In particular, TiO2 mesocrystals, which are built from TiO2 nanocrystal building blocks in the same crystallographical orientation, have attracted intensive research interest in the area of photocatalysis owing to their distinctive structural properties such as high crystallinity, high specific surface area, and single-crystal-like nature. The deeper understanding of TiO2 mesocrystals-based photocatalysis is beneficial for developing new types of photocatalytic materials with multiple functionalities. In this paper, a comprehensive review of the recent advances toward fabricating and modifying TiO2 mesocrystals is provided, with special focus on the underlying mesocrystallization mechanism and controlling rules. The potential applications of as-synthesized TiO2 mesocrystals in photocatalysis are then discussed to shed light on the structure–performance relationships, thus guiding the development of highly efficient TiO2 mesocrystal-based photocatalysts for certain applications. Finally, the prospects of future research on TiO2 mesocrystals in photocatalysis are briefly highlighted.

scholarly journals Evaluation of the Physico-Chemical Properties of Liposomes Assembled from Bioconjugates of Anisic Acid with Phosphatidylcholine

2021 ◽  
Vol 22 (23) ◽  
pp. 13146
Author(s):  
Hanna Pruchnik ◽  
Anna Gliszczyńska ◽  
Aleksandra Włoch
Keyword(s):  
Phase Transition ◽  
Lipid Bilayer ◽  
Chemical Properties ◽  
Main Phase ◽  
Cancer Therapies ◽  
Dependent Manner ◽  
Scanning Calorimetry ◽  
Physico Chemical ◽  
Anisic Acid ◽  
The Impact

The aim of this work was the evaluation of the physico-chemical properties of a new type of liposomes that are composed of DPPC and bioconjugates of anisic acid with phosphatidylcholine. In particular, the impact of modified anisic acid phospholipids on the thermotropic parameters of liposomes was determined, which is crucial for using them as potential carriers of active substances in cancer therapies. Their properties were determined using three biophysical methods, namely differential scanning calorimetry (DSC), steady-state fluorimetry and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Moreover, temperature studies of liposomes composed of DPPC and bioconjugates of anisic acid with phosphatidylcholine provided information about the phase transition, fluidity regarding chain order, hydration and dynamics. The DSC results show that the main phase transition peak for conjugates of anisic acid with phosphatidylcholine molecules was broadened and shifted to a lower temperature in a concentration- and structure-dependent manner. The ATR-FTIR results and the results of measurements conducted using fluorescent probes located at different regions in the lipid bilayer are in line with DSC. The results show that the new bioconjugates with phosphatidylcholine have a significant impact on the physico-chemical properties of a membrane and cause a decrease in the temperature of the main phase transition. The consequence of this is greater fluidity of the lipid bilayer.

scholarly journals FORMULATION AND EVALUATION OF PRESS COATED TABLETS OF LANSOPRAZOLE

2019 ◽  
pp. 49-56
Author(s):  
Prasanthi D ◽  
PRASHANTI. S ◽  
MEGHANA G
Keyword(s):  
Ethyl Cellulose ◽  
Chemical Properties ◽  
Enteric Coating ◽  
Scanning Calorimetry ◽  
Dsc Studies ◽  
Delayed Release ◽  
Ich Guidelines ◽  
Physico Chemical ◽  
Enteric Coated ◽  
Core Tablet

Objective: Lansoprazole an proton pump inhibitor, degrades in acidic environment, hence protection of drug is done by coating the drug with enteric coating polymers. The aim and objective of the present study was to prepare enteric coated delayed release tablets of lansoprazole by using press coating technique. Methods: Core tablets were prepared by direct compression and evaluated for their physico-chemical properties. Press coated tablets were formulated by using different combinations of ethyl cellulose, HPMC E15 and HPMC K4M as a coating layer. Core and coated tablets were optimized by dissolution studies. Fourier transform infra-red spectroscopy (FTIR) and differential scanning calorimetry (DSC) studies were performed to know the compatibility of drug with various excipients. Surface morphology and uniformity of coat was evaluated by Scanning electron microscopy (SEM). Stability of optimized formulation was evaluated according to ICH guidelines. Results: Among the various formulations F5 containing ethyl cellulose: HPMC E15 (10:90) and F9 containing ethyl cellulose: HPMC K4M (25:75) were optimized based on the better drug release within 8 h. DSC studies and FTIR studies revealed compatibility of drug with excipients. Obtained SEM photographs of tablets showed that the surface of core tablet is uniformly coated with coat by press coating. Stability studies showed that the formulations were stable. Conclusion: As a result, delayed release press coated tablets developed in this study delivered lansoprazole in the intestine and protected the drug from degradation.

Extraction of Collagen from Catfish (Clarias gariepnus) Waste and Determination of its Physico-chemical Properties

2012 ◽  
Vol 9 (1) ◽  
pp. 29
Author(s):  
Normah Ismail ◽  
Nurul Asyiraf Abdul Jabar
Keyword(s):  
Thermal Stability ◽  
Food Industry ◽  
Chemical Properties ◽  
White Crystal ◽  
Scanning Calorimetry ◽  
Good Thermal Stability ◽  
Physico Chemical ◽  
Pale Colour ◽  
Increasing Temperature

Collagen was extracted from catfish (Clarias gariepnus) waste using 0.5M acetic acid and its subsequent precipitation in 2.6M NaCl. The resultant collagen was analysed with respect to its moisture content and physico­chemical properties including yield, pH, protein content, colour, odour and thermal stability. A yield of 16. 4% and positive collagen attributes indicate that catfish waste has potential as a collagen source. The snowy white, crystal-like and light textured collagen comprises of 5.97% protein and 0.46% moisture, and exhibits a pH of 4.75. Sensory evaluation indicates that the collagen has a slight fishy odour. Viscosity analysis indicates a steady decrease with increasing temperature over the range considered (20-50°C). The pale colour exhibited and limited odour emitted by the extracted collagen indicate that catfish waste collagen could be applied in the food industry without resulting in any undesirable food products attributes. Differential Scanning Calorimetry (DSC) analysis indicated that the collagen exhibits good thermal stability and denatures at a high temperature in a similar manner to mammalian collagen.

Oxide thin film properties

2021 ◽  
pp. 84-126
Author(s):  
Falko P. Netzer ◽  
Claudine Noguera
Keyword(s):  
Thin Films ◽  
Chemical Reactivity ◽  
Finite Thickness ◽  
Chemical Properties ◽  
Local Environment ◽  
Oxide Thin Film ◽  
Special Focus ◽  
Physico Chemical ◽  
Oxide Substrates ◽  
Interfacial Dislocations

Chapter 4 focuses on the various physico-chemical properties of thin films, and in particular on their thickness dependence. It aims at bridging the gap between the well established knowledge acquired on oxide surfaces and truely two-dimensional oxides. It reviews the consequences of the reduced local environment of their atoms and of the confinement effects due to their finite thickness. It analyzes the various manifestations of structural, electronic, vibrational, ferroelectric and magnetic modifications. A special focus is put on the interaction of thin films with metal or oxide substrates, possibly leading to interfacial dislocations, electron transfer or mixing, with consequences on their chemical reactivity.

scholarly journals Synthesis and Application of a Cationic Polyamine as Yankee Dryer Coating Agent for the Tissue Paper-Making Process

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 173
Author(s):  
Cesar Valencia ◽  
Yamid Valencia ◽  
Carlos David Grande Tovar
Keyword(s):  
Chemical Properties ◽  
Gel Permeation Chromatography ◽  
Superior Performance ◽  
Production Plant ◽  
Scanning Calorimetry ◽  
Release Agent ◽  
Coating Agent ◽  
Tissue Paper ◽  
Paper Making ◽  
Durability Assessment

Tissue paper is of high importance worldwide and, continuously, research is focused on improvements of the softening and durability properties of the paper which depend specifically on the production process. Polyamide-amine-epichlorohydrin (PAE) resins along with release agents are widely used to adhere the paper to the yankee dryer (creping cylinder) in paper manufacture. Nevertheless, these resins are highly cationic and they normally adhere in excess to the paper which negatively affects the creping process and the quality of the paper. For this reason, a low cationic polyamine-epichlorohydrin coating (Polycoat 38®) was synthesized from a diamine supplied by Disproquin S.A.S. and epichlorohydrin. The analysis of the synthesized polymer was carried out by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H-NMR). The molecular weight of the polymer was obtained by gel permeation chromatography (GPC), physical-chemical properties such as kinematic viscosity, percentage of solids, density, charge density were measured and compared with a commercial PAE resin (Dispro620®) Thermal stability of the Polycoat 38® and glass transition temperature in presence of a release agent (Disprosol 17®) were also evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively. Finally, a peel adhesion test and an absorption durability assessment were carried out together with the evaluation of the creeping efficiency of the paper by caliber and tensile measurements in a tissue (towel paper) production plant, demonstrating a superior performance in the paper creping process as compared to some commercially available products.

Halloysite nanotubes with fluorinated cavity: an innovative consolidant for paper treatment

Clay Minerals ◽  
2016 ◽  
Vol 51 (3) ◽  
pp. 445-455 ◽  
Author(s):  
Giuseppe Cavallaro ◽  
Giuseppe Lazzara ◽  
Stefana Milioto ◽  
Filippo Parisi
Keyword(s):  
Chemical Properties ◽  
Halloysite Nanotubes ◽  
Scanning Calorimetry ◽  
Cellulose Fibres ◽  
Green Protocol ◽  
Cellulose Structure ◽  
Combustion Enthalpy ◽  
Physico Chemical ◽  
Mesoscopic Structure ◽  
Sodium Perfluorooctanoate

AbstractHybrid material based on halloysite nanotubes (HNTs) and sodium perfluorooctanoate (NaPF8) was used as a consolidant for paper treatment. The consolidation efficiency was determined by thermogravimetry as well as by paper grammage determination. Morphological analysis of the treated paper was performed by means of scanning electron microscopy while the effect of modified HNTs on the thermal behaviour of the cellulose fibres was investigated by differential scanning calorimetry which determined the combustion enthalpy of the paper.Water contact angle measurements were performed to study the paper wettability. The physico-chemical properties investigated (mesoscopic structure, thermal stability and wettability) of the treated paper were correlated successfully with the consolidation loading and, consequently, to the affinity between the fluorinated modified HNTs and the fibrous cellulose structure. This study proposes a new green protocol for paper consolidation based on natural tubular nanoparticles with a flame retardant effect.

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