scholarly journals Preparation and Characterization of Chitosan/Agar Blended Films: Part 2. Thermal, Mechanical, and Surface Properties

2012 ◽  
Vol 9 (2) ◽  
pp. 510-516 ◽  
Author(s):  
Esam A. Elhefian ◽  
Mohamed Mahmoud Nasef ◽  
Abdul Hamid Yahaya
Keyword(s):  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Water Contact ◽  
Elongation At Break ◽  
Angle Measurements ◽  
Static Water Contact Angle ◽  
Contact Angle Measurements ◽  
Static Water ◽  
Thermal Stability Of

Chitosan/agar (CS/AG) films were prepared by blending different proportions of chitosan and agar (considering chitosan as the major component) in solution forms. The thermal stability of the blended films was studied using thermal gravimetric analysis (TGA). It was revealed that chitosan and agar form a compatible blend. Studying the mechanical properties of the films showed a decrease in the tensile strength and elongation at break with increasing agar content. Blending of agar with chitosan at all proportions was found to form hydrogel films with enhanced swelling compared to the pure chitosan one. Static water contact angle measurements confirmed the increasing affinity of the blended films towards water suggesting that blending of agar with chitosan improves the wettability of the obtained films.

scholarly journals Preparation and Characterization of Chitosan/Poly(Vinyl Alcohol) Blended Films: Mechanical, Thermal and Surface Investigations

2011 ◽  
Vol 8 (1) ◽  
pp. 91-96 ◽  
Author(s):  
Esam A. El-Hefian ◽  
Mohamed Mahmoud Nasef ◽  
Abdul Hamid Yahaya
Keyword(s):  
Contact Angle ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
Water Contact ◽  
Elongation At Break ◽  
Angle Measurements ◽  
Static Water Contact Angle ◽  
Contact Angle Measurements ◽  
Static Water

In this study, blends of chitosan (CS) and polyvinyl alcohol (PVA) (CS/PVA) having various proportions were prepared and characterized by universal mechanical tester, the differential scanning calorimetry (DSC) and contact angle measurements. Studying the mechanical properties of the films showed that blending improved the tensile strength, which increased with increasing PVA content up to 40% while the elongation% at break of the blends was decreased compared to that of the pure components. The obtained results of DSC suggested that some interaction between chitosan and PVA mostly took place. Static water contact angle measurements showed an improvement in the wettability of the obtained films.

scholarly journals Study of the Properties of the Porous Silicon Synthesized by Ag Assisted Chemical Etching

2016 ◽  
Vol 71 ◽  
pp. 40-48 ◽  
Author(s):  
Madhavi Karanam ◽  
G. Mohan Rao ◽  
Shaik Habibuddin ◽  
R. Padmasuvarna
Keyword(s):  
Porous Silicon ◽  
Etching Time ◽  
Photoluminescence Spectra ◽  
Hydrophobic Properties ◽  
Water Contact ◽  
Optical Absorbance ◽  
Angle Measurements ◽  
Static Water Contact Angle ◽  
Contact Angle Measurements ◽  
Static Water

Porous Silicon (PSi) is synthesized by Ag assisted electroless etching and characterized by Scanning electron microscopy (SEM). The effect of etching time on the optical reflectivity, optical absorbance of PSi is investigated. Reflectivity measurements showed that 45% reflectivity Si wafers drops from 45% to 10% for 2 hours etching and 6% for 3 hours etching. The decrease in the reflectivity shows that the PSi can be employed as an anti reflecting substrate in optoelectronic devices. The absorbance measurements reveal that the average absorbance of PSi is 0.60 in the wavelength range 300-800 nm after 2 hours etching. From the photoluminescence spectra it was found that PL intensity of PSi is high compared to bare silicon wafer. Static water contact angle measurements were performed to examine the hydrophobic properties of the PSi prepared under different conditions.

Synthesis and characterization of diaminomaleonitrile-functionalized polystyrene grafts for application in pervaporation separation

2008 ◽  
Vol 62 (4) ◽  
Author(s):  
Hamada Abdel-Razik
Keyword(s):  
Chemical Structure ◽  
Thermal Characteristics ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Optimum Conditions ◽  
Scanning Calorimetry ◽  
Phenol Water ◽  
Pervaporation Separation ◽  
Thermal Stability Of

AbstractSynthesis, characterization and application of diaminomaleonitrile (DAMN)-functionalized polystyrene grafts were studied. Dibenzoyle peroxide (BP) was used as an initiator. Optimum conditions for grafting were found to be c(DAMN) = 0.5 M, c(BP) = 0.016 M, θ = 85 °C and t = 4 h. Water uptake of the polystyrene graft membranes was found to increase with the increase of the grafting yield. The chemical structure, thermal characteristics and thermal stability of the obtained membranes were investigated by means of FTIR spectroscopy, differential scanning calorimetry, and thermal gravimetric analysis. Polystyrene graft membrane with the degree of grafting of up to 96 % was found to be useful for the pervaporation separation of phenol/water mixtures.

scholarly journals Solid-State Compounding for Recycling of Sawdust Waste into Green Packaging Composites

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1386
Author(s):  
Rula M. Allaf ◽  
Mohammad Futian
Keyword(s):  
Solid State ◽  
Thermo Gravimetric Analysis ◽  
Contact Angles ◽  
Raw Material ◽  
Potential Candidate ◽  
Gravimetric Analysis ◽  
Water Contact ◽  
Elongation At Break ◽  
Green Packaging ◽  
Thermal Stability Of

The present study explores solid-state cryomilling for the compounding of green composites. Herein, wood plastic composites (WPCs) composed of sawdust (SD) and poly(ε-caprolactone) (PCL) with various compositions were prepared. Two compounding techniques, namely, extrusion and cryomilling, were utilized to prepare WPC raw material pellets and powders, respectively, for comparison purposes. Flat pressing was further utilized to prepare WPC films for testing. Morphological, structural, thermal, mechanical, and surface wettability properties were investigated. Results indicate the advantages of cryomilling in producing WPCs. Scanning electron microscopy (SEM) along with optical micrographs revealed well ground SD particles and uniform distribution in the PCL matrix. Tensile strength and elongation at break of the composites declined with increasing SD content, however, the modulus of elasticity significantly increased. Water contact angles averaged less than 90°, implying partial wetting. Visual observations and thermo-gravimetric analysis (TGA) indicated thermal stability of composites during processing. In conclusion, PCL/SD WPC is a potential candidate to replace conventional plastics for packaging applications. This would also provide a much better utilization of the currently undervalued wood waste resources.

Temperature Stability Of Plasma Polymerized Antiadhesive Coatings

1998 ◽  
Vol 544 ◽  
Author(s):  
W. Michaeli ◽  
R. Dahlmann ◽  
I. Fonteiner
Keyword(s):  
Surface Tension ◽  
Photoelectron Spectroscopy ◽  
Thermo Gravimetric Analysis ◽  
Temperature Stability ◽  
Polymer Coatings ◽  
Gravimetric Analysis ◽  
Angle Measurements ◽  
Wide Range ◽  
Contact Angle Measurements ◽  
Thermal Stability Of

AbstractBy means of microwave-assisted plasma polymerization it is possible to deposit polymer coatings on different surfaces such as plastics or metals. The surface tension can be influenced in a wide range. However, many applications require a high thermal stability of such low surface tension layers. Therefore, the influence of variations of the process parameters on temperature stability of such layers is examined. The produced layers were studied regarding their chemical and physical characteristics under temperature influence by means of contact angle measurements, xray photoelectron spectroscopy (XPS), thermo gravimetric analysis (TGA) combined with Fouriertransformed infrared spectroscopy (FTIR). Fluorine containing monomers offer good perspectives. Up to temperatures of approx. 200°C the antiadhesivity of these coatings is adjustable to values close to those of poly(tetrafluoroethylene) (PTFE).

Preparation and Characterization of Polymer/Multi-Walled Carbon Nanotube Nanocomposites

2008 ◽  
Vol 140 ◽  
pp. 97-102 ◽  
Author(s):  
M. Sarah Mohlala ◽  
Suprakas Sinha Ray
Keyword(s):  
Gravimetric Analysis ◽  
Melt Blending ◽  
Thermal Gravimetric ◽  
Scanning Calorimetry ◽  
Multiwalled Carbon ◽  
Nanostructured Composite ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotube ◽  
Thermal Stability Of

This paper describes the preparation, characterization and properties of nanostructured composite materials based on poly(butylene adipate-co-polycaprolactam) (PBA-co-PCL)/multiwalled carbon nanotubes (MWCNTs) and polycaprolactone (PCL)/MWCNTs. The polymer/MWCNTs nanocomposites were prepared by mixing the polymers with various amounts of MWCNTs using both solution and melt blending processes. The dispersion of MWCNTs into the polymer matrix was analyzed by transmission electron microscopy (TEM) and the thermal stability of the nanocomposites was studied by thermal gravimetric analysis (TGA). Differential scanning calorimetry (DSC) was used to study the crystallization and melting behaviour of the polymer matrices containing the MWCNTs.

scholarly journals Synthesis and characterization of hydrophobic, ultra-fine fibres based on an organic–inorganic nanocomposite containing a polyimide functionality

2019 ◽  
Vol 27 (5) ◽  
pp. 268-278
Author(s):  
Christian Schramm ◽  
Beate Rinderer ◽  
Richard Tessadri
Keyword(s):  
Fibre Diameter ◽  
Precursor Solution ◽  
Amic Acid ◽  
Water Contact ◽  
X Ray ◽  
Angle Measurements ◽  
Fine Fibre ◽  
Contact Angle Measurements ◽  
Electrospinning Method

Ultra-thin polyimide fibres were fabricated by means of the electrospinning method by using precursor solutions consisting of the organotrialkoxysilanes (3-triethoxysilylpropyl)succinic anhydride (TESP-SA), (3-amino)propyltriethoxysilane (APTES), tetraethoxysilane (TEOS) and methyltriethoxysilane (MTEOS). TESP-SA and APTES were reacted to the corresponding poly(amic)acid (PAA) in an aqueous medium which was electrospun at 15 kV and at a tip to collector distance of 15 cm. TEOS and MTEOS were also incorporated into the precursor solution to modify the surface properties of the ultra-fine fibre mat. The fibre diameter distributions of the as-prepared PAA fibres were measured. The PAA fibres were thermally treated at 220°C resulting in the formation of an organic–inorganic hybrid polyimide fibre mat with ladder-like structure, as could be shown by Fourier transform infrared spectroscopy and X-ray powder diffraction. The ultra-fine fibre assemblies were also characterized by means of scanning electron microscopy, thermogravimetric analysis and water contact angle measurements.

Characterization of 3C-SiC (100) as a platform for detecting the onset of acute myocardial infarction (AMI)

2012 ◽  
Vol 1433 ◽  
Author(s):  
Alexandra Oliveros ◽  
Anthony Guiseppi-Elie ◽  
Mark Jaroszeski ◽  
Stephen E. Saddow
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Contact Angle ◽  
Layer Formation ◽  
Water Contact ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements

ABSTRACTIn this work we describe the characterization of anti-myoglobin immobilization on 3C-SiC (100) by means of surface modification with 3-aminopropyltriethoxysilane (APTES). Surface water contact angle measurements were used to compare the wettability of 3C-SiC (100) before (16 ±3°) and after APTES layer formation (61 ±1°). Atomic force microscopy (AFM) was used to confirm the homogenous formation of APTES and anti-myoglobin immobilization with EDC-sulfo NHS coupling. For the APTES surfaces no significant change in the surface roughness was obtained whereas with anti-myoglobin surfaces, particles on the order of ∼60 nm in diameter with a globular shape were observed.

scholarly journals The Preparation and Characterization of Chitosan / Poly (Vinyl Alcohol) Blended Films

2010 ◽  
Vol 7 (4) ◽  
pp. 1212-1219 ◽  
Author(s):  
Esam A. El-Hefian ◽  
Mohamed Mahmoud Nasef ◽  
Abdul Hamid Yahaya
Keyword(s):  
Smooth Surface ◽  
Chemical Structure ◽  
Poly Vinyl Alcohol ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Blend Films ◽  
Main Component ◽  
Thermal Stability Of ◽  
Scanning Electron

In this study, chitosan and PVA were blended at different proportions (considering chitosan as the main component) in solution forms. The chemical structure and the morphology of the obtained blend films were investigated using FTIR and field emission scanning electron microscope (FESEM). The thermal stability of the blend films were also studied using thermal gravimetric analysis (TGA). Our results showed that chitosan and PVA form a compatible blend and their films displayed homogenous and smooth surface properties compared to their individual pure components. The blending of PVA with chitosan at all proportions was found to highly enhance the swelling of the obtained films compared to that of pure chitosan one.

Nanostructured Polymer Brushes With Reversibly Changing Properties

2002 ◽  
Vol 727 ◽  
Author(s):  
Denys Usov ◽  
Manfred Stamm ◽  
Sergiy Minko ◽  
Christian Froeck ◽  
Andreas Scholl ◽  
...  
Keyword(s):  
Polymer Brushes ◽  
Phase Segregation ◽  
Water Contact ◽  
Angle Measurements ◽  
Nanostructured Polymer ◽  
Contact Angle Measurements ◽  
Vertical Segregation ◽  
Oxygen Plasma Etching ◽  
Grafting From ◽  
Photoemission Electron

AbstractWe investigated the interplay between different mechanisms of the lateral and vertical segregation in the synthesized via “grafting from” approach symmetric A/B (where A and B are poly(styrene-co-2,3,4,5,6-pentafluorostyrene) and poly(methylmethacrylate), respectively) polymer brushes upon exposure to different solvents. We used X-ray photoemission electron spectroscopy and microscopy (X-PEEM), AFM, water contact angle measurements, and oxygen plasma etching to study morphology of the brushes. The ripple morphology after toluene (nonselective solvent) revealed elongated lamellar-like domains of A and B polymers alternating across the surface. The dimple-A morphology consisting of round clusters of the polymer A was observed after acetone (selective solvent for B). The top layer was enriched with the polymer B showing that the brush underwent both the lateral and vertical phase segregation. A qualitative agreement with predictions of SCF theory was found.

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