scholarly journals Preparation and characterization of poly(urethane-siloxane)/titanium-dioxide nanocomposites

2019 ◽  
Vol 73 (1) ◽  
pp. 13-24 ◽  
Author(s):  
Ivan Stefanovic ◽  
Jasmina Dostanic ◽  
Davor Loncarevic ◽  
Dana Vasiljevic-Radovic ◽  
Sanja Ostojic ◽  
...  
Keyword(s):  
Free Energy ◽  
Titanium Dioxide ◽  
Surface Free Energy ◽  
In Situ Polymerization ◽  
Diffuse Reflectance Spectroscopy ◽  
Protective Coatings ◽  
Uv Resistance ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Relief Structure

This work is focused on preparation of poly(urethane-siloxane)/titanium-dioxide nanocompo-sites (PUSNs) with enhanced features. PUSNs were prepared by the in situ polymerization re-action using titanium-dioxide as a nano-filler in different amounts (1, 2, 3 and 5 wt.%) with respect to the poly(urethane-siloxane) (PUS) matrix. PUS copolymer was based on ?,?-dihy-droxy-ethoxypropyl-poly(dimethylsiloxane), 4,4?-methylenediphenyldiisocyanate and 1,4-bu-tanediole. In order to investigate the influence of TiO2 content on the structure, UV resistance, thermal properties, hydrophobicity and morphology of the prepared PUSNs, FTIR spectro-scopy, UV-Vis diffuse-reflectance spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), contact angle measurements, surface free energy (SFE) analysis, water absorption, scanning electron microscopy (SEM) and atomic force microscopy (AFM) were performed. The PUSNs showed excellent UV resistance, high hydrophobicity, low surface free energy and also higher thermal stability and rougher surface and cross-section relief structure as compared to the pure PUS copolymer. Based on the obtained results it can be concluded that prepared PUSNs could be potentially used as protective coatings.

Structure and Properties of Hybrid Polyurethane Composites with Carboxyalumoxanes

2008 ◽  
Vol 587-588 ◽  
pp. 212-216 ◽  
Author(s):  
Magdalena Jurczyk-Kowalska ◽  
Joanna Ryszkowska
Keyword(s):  
In Situ Polymerization ◽  
Structure And Properties ◽  
Mechanical Mixing ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Matrix ◽  
Polyurethane Composites ◽  
Polyurethane Matrix

Carboxyalumoxanes have been incorporated into a polyurethane matrix by in situ polymerization. The filler was dispersed in the polyurethane matrix by either both ultrasonic and mechanical mixing or by mechanical mixing alone. The physico-mechanical properties of the composites have been characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Using ultrasound improves the degree of dispersion of the fillers in the matrix, but it also causes changes in the structure of the polyurethane matrix.

Biopolymer Blends as Potential Biomaterials and Cosmetic Materials

2013 ◽  
Vol 583 ◽  
pp. 95-100 ◽  
Author(s):  
Alina Sionkowska ◽  
Katarzyna Lewandowska ◽  
A. Planecka ◽  
P. Szarszewska ◽  
K. Krasinska ◽  
...  
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Surface Free Energy ◽  
Silk Fibroin ◽  
High Surface ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Polymeric Blends ◽  
Contact Angle Measurements

Blends of two polymer, namely chitosan with silk fibroin or partially hydrolysed polyacrylamide (HPAM) were prepared. The surface properties of chitosan/silk fibroin and chitosan/HPAM blended films were investigated using the technique of Atomic Force Microscopy (AFM) and by means of contact angle measurements allowing the calculation of surface free energy. Measurements of the contact angle for diiodomethane (D), and glycerol (G) on the surface of chitosan films and chitosan/silk fibroin films were made and surface free energy was calculated. It was found that chitosan/silk fibroin blend surface is enriched in high surface energy component i.e. silk fibroin. The surface roughness of chitosan, silk fibroin, HPAM, chitosan/silk fibroin and chitosan/HPAM blended films differs with the composition of the blend. Film-forming polymeric blends can be potentially used as biomaterials and cosmetic materials.

scholarly journals Superiority of Cellulose Non-Solvent Chemical Modification over Solvent-Involving Treatment: Application in Polymer Composite (part II)

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2901 ◽  
Author(s):  
Stefan Cichosz ◽  
Anna Masek
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Natural Fibers ◽  
Degradation Process ◽  
Mechanical Analysis ◽  
Planetary Mill ◽  
Scanning Calorimetry ◽  
Static Mechanical ◽  
Ft Ir ◽  
Composite Samples

The following article debates on the properties of cellulose-filled ethylene-norbornene copolymer (EN) composites. Natural fibers employed in this study have been modified via two different approaches: solvent-involving (S) and newly developed non-solvent (NS). The second type of the treatment is fully eco-friendly and was carried out in the planetary mill without incorporation of any additional, waste-generating substances. Composite samples have been investigated with the use of spectroscopic methods (FT-IR), differential scanning calorimetry (DSC), static mechanical analysis, and surface-free energy measurements. It has been proved that the possible filler-polymer matrix interaction changes may occur due to the performed modifications. The highest reinforcement was evidenced for the composite sample filled with cellulose treated via a NS approach—TS = (34 ± 2) MPa, Eb = (380 ± 20)%. Additionally, a surface free energy polar part exhibited a significant increase for the same type of modification. Consequently, this could indicate easier wetting of the material which may contribute to the degradation process enhancement. Successfully developed cellulose-filled ethylene-norbornene copolymer composite compromises the rules of green chemistry and sustainable development by taking an advantage of renewable natural resources. This bio-inspired material may become an eco-friendly alternative for commonly used polymer blends.

Surface Modification of Polyetheretherketone by Helium/nitrogen and Nitrous Oxide Plasma Enhanced Chemical Vapour Deposition

2014 ◽  
Vol 33 (2) ◽  
pp. 147-153
Author(s):  
Stanisława Kluska ◽  
Elżbieta Pamuła ◽  
Stanisława Jonas ◽  
Zbigniew Grzesik
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Photoelectron Spectroscopy ◽  
Sessile Drop ◽  
Chemical Vapour ◽  
Chemical Vapor ◽  
Morphological Characterization ◽  
Polar Component ◽  
Force Microscopy ◽  
Atomic Force

AbstractThe surface of the polyetheretherketone (PEEK) samples was modified by the plasma enhanced chemical vapor deposition (PECVD) in the mixture of He and N2 as well as in the N2O atmosphere. Morphological characterization of the PEEK as well as its surface roughness, chemical structure, and surface free energy were investigated by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and sessile drop technique, respectively. The highest increase in the polar component of the total surface energy was observed for PEEK modified by He+N2 plasma, which correlated with significant increase in the concentration of oxygen and nitrogen-containing chemical functionalities as revealed by XPS. For PEEK submitted to N2O plasma treatment significant changes in surface topography and increase in roughness were observed, but changes in surface chemistry and surface free energy were mild.

Measurement of the Surface Free Energy of Streptavidin Crystals by Atomic Force Microscopy

Langmuir ◽  
2003 ◽  
Vol 19 (7) ◽  
pp. 2908-2912 ◽  
Author(s):  
Annalisa Relini ◽  
Silvia Sottini ◽  
Simone Zuccotti ◽  
Martino Bolognesi ◽  
Alessandra Gliozzi ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Free Energy ◽  
Surface Free Energy ◽  
Force Microscopy ◽  
Atomic Force

The effects of humidity and surface free energy on adhesion force between atomic force microscopy tip and a silane self-assembled monolayer film

2010 ◽  
Vol 25 (3) ◽  
pp. 556-562 ◽  
Author(s):  
Chien-Chao Huang ◽  
Lijiang Chen ◽  
Xiaohong Gu ◽  
Minhua Zhao ◽  
Tinh Nguyen ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Free Energy ◽  
Surface Free Energy ◽  
Adhesion Force ◽  
Capillary Condensation ◽  
Self Assembled Monolayer ◽  
Force Microscopy ◽  
Atomic Force ◽  
Rate Of Increase ◽  
Self Assembled

The relationship between atomic force microscopy probe-sample adhesion force and relative humidity (RH) at five different levels of surface free energy (γs) of an organic self-assembled monolayer (SAM) has been investigated. Different γs levels were achieved by exposing a patterned SiO2/CH3-terminated octyldimethylchlorosilane SAM sample to an ultraviolet (UV)/ozone atmosphere. A model consisting of the Laplace-Kelvin theory for capillary condensation for nanosized probe and probe-sample molecular interaction was derived to describe the adhesion force as a function of RH from 25 to 90% for different SAM γs values. The equations were solved analytically by using an equivalent curvature of the probe tip shape. Experimental results show that the adhesion force increases slightly with RH for nonpolar SAM. However, for polar SAM surfaces, it increases at first, reaches a maximum, and then decreases. Both the rate of increase and the maximum of the adhesion force with humidity are γs-dependent, which is in good agreement with theoretical prediction. The large rise in the adhesion force in this RH range is due to the capillary force.

scholarly journals Synthesis and Study of Morphology and Biocompatibility of Xanthan Gum/Titanium Dioxide-Based Polyurethane Elastomers

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3416
Author(s):  
Shazia Naheed ◽  
Muhammad Shahid ◽  
Rashida Zahoor ◽  
Zumaira Siddique ◽  
Nasir Rasool ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Titanium Dioxide ◽  
Xanthan Gum ◽  
Diffusion Method ◽  
Scanning Calorimetry ◽  
Polyurethane Elastomers ◽  
Force Microscopy ◽  
Microscopy Technique ◽  
Atomic Force ◽  
Final Sample

A series of xanthan gum/titanium dioxide-based polyurethane elastomers were synthesized through the prepolymer method by the step growth polymerization. In the present work, xanthan gum was used as a bioactive material, with TiO2 as a nanofiller. The structural characterization of newly prepared polyurethane samples was carried out with the help of Fourier Transform Infrared Spectroscopy. Thermogravimetric Analysis gave us the information about the thermal stability. Differential Scanning Calorimetry directs the thermal changes in the polyurethane samples. The Atomic Force Microscopy technique revealed that the degree of micro-phase separation increases by augmenting the % age of TiO2, which was further confirmed by X-Ray Diffraction results. XRD confirmed the crystallinity of the final sample at about 2θ = 20°. Antimicrobial activity determined through the Disc Diffusion Method, and the results indicated that the synthesized polyurethane have antimicrobial activity. The water absorption capability of the polyurethane samples showed that these polymer samples are hydrophilic in nature.

Determination of the Surface Free Energy of Crystalline and Amorphous Lactose by Atomic Force Microscopy Adhesion Measurement

2006 ◽  
Vol 23 (2) ◽  
pp. 401-407 ◽  
Author(s):  
Jianxin Zhang ◽  
Stephen Ebbens ◽  
Xinyong Chen ◽  
Zheng Jin ◽  
Shen Luk ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Free Energy ◽  
Surface Free Energy ◽  
Force Microscopy ◽  
Atomic Force ◽  
Adhesion Measurement ◽  
Amorphous Lactose

scholarly journals Improvement in Solubility and Absorption of Nifedipine Using Solid Solution: Correlations between Surface Free Energy and Drug Dissolution

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2963
Author(s):  
Sukannika Tubtimsri ◽  
Yotsanan Weerapol
Keyword(s):  
Solid Solution ◽  
Free Energy ◽  
Surface Free Energy ◽  
Cellular Uptake ◽  
Solid Solutions ◽  
Drug Dissolution ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Drug Permeability ◽  
Methacrylate Copolymer

Ternary solid solutions composed of nifedipine (NDP), amino methacrylate copolymer (AMCP), and polysorbate (PS) 20, 60, or 65 were prepared using a solvent evaporation method. The dissolution profiles of NDP were used to study the effect of the addition of polysorbate based on hydrophilic properties. A solid solution of NDP and AMCP was recently developed; however, the dissolution of NDP was <70%. In the present study, polysorbate was added to improve the dissolution of the drug by altering its hydrophilicity. The suitable formulation contained NDP and AMCP at a ratio of 1:4 and polysorbate at a concentration of 0.1%, 0.3%, or 0.6%. Differential scanning calorimetry and powder X-ray diffraction were used to examine the solid solutions. No peak representing crystalline NDP was observed in any solid solution samples, suggesting that the drug was molecularly dispersed in AMCP. The NDP dissolution from NDP powder and solid solution without PS were 16.82% and 58.19%, respectively. The highest dissolution of NDP of approximately 95.25% was noted at 120 min for the formulation containing 0.6% PS20. Linear correlations were observed between the surface free energy and percentages of dissolved NDP (R2 = 0.7115–0.9315). Cellular uptake across Caco-2 was selected to determine the drug permeability. The percentages of cellular uptake from the NDP powder, solid solution without and with PS20 were 0.25%, 3.60%, and 7.27%, respectively.

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