scholarly journals Influence of Ultraviolet Radiation Exposure Time on Styrene-Ethylene-Butadiene-Styrene (SEBS) Copolymer

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 862 ◽  
Author(s):  
Daniel Garcia-Garcia ◽  
José Enrique Crespo-Amorós ◽  
Francisco Parres ◽  
María Dolores Samper
Keyword(s):  
Surface Energy ◽  
Ultraviolet Radiation ◽  
Mechanical Performance ◽  
Polymer Materials ◽  
Attenuated Total Reflectance ◽  
Force Microscopy ◽  
Atomic Force ◽  
Ultraviolet Radiation Exposure ◽  
Physical Changes ◽  
Butadiene Styrene

The effect of ultraviolet radiation on styrene-ethylene-butadiene-styrene (SEBS) has been studied at different exposures times in order to obtain a better understanding of the mechanism of ageing. The polymer materials were mechanically tested and then their surfaces were analyzed using a scanning electron microscope (SEM) and atomic force microscopy (AFM). Moreover, the optical analysis of contact angle (OCA) was used to evaluate the surface energy (γs) and the yellowing index (YI) and attenuated total reflectance infrared spectroscopy (ATR–FTIR) were used to observe structural and physical changes in aging SEBS. The results obtained for the SEBS, in relation to the duration of exposure, showed superficial changes that cause a decrease in the surface energy (γs) and, therefore, a decrease in surface roughness. This led to a reduction in mechanical performance, decreasing the tensile strength by about 50% for exposure times of around 200 h.

TUNING PROPERTIES AND MORPHOLOGY IN HIGH VINYL CONTENT SBS BLOCK COPOLYMER, A THERMOPLASTIC ELASTOMER VIA THIOL-ENE MODIFICATION

2017 ◽  
Vol 90 (3) ◽  
pp. 550-561 ◽  
Author(s):  
Prithwiraj Mandal ◽  
Siva Ponnupandian ◽  
Soumyadip Choudhury ◽  
Nikhil K. Singha
Keyword(s):  
Block Copolymer ◽  
Thermoplastic Elastomer ◽  
Atomic Force Microscopy Analysis ◽  
Ene Reaction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Microscopy Analysis ◽  
Styrene Butadiene Styrene ◽  
Styrene Butadiene ◽  
Butadiene Styrene

ABSTRACT Thiol-ene modification of high vinyl content thermoplastic elastomeric styrene butadiene styrene (SBS) block copolymer (BCP) was carried out using different thiolating agents in toluene at 70 °C. 1H NMR analysis confirmed the participation of vinyl double bond in the thiol-ene modification reaction of SBS. Surface morphology of the block copolymers evaluated by atomic force microscopy analysis showed higher roughness after the thiol-ene reaction. The thiol-modified SBS block copolymer showed better adhesion strength and oil resistance properties than the pristine SBS.

Preparation and Characterization of Chitosan-Casein Phosphopeptides Biocomposite Coatings on the Medical Titanium Alloy

2011 ◽  
Vol 480-481 ◽  
pp. 1065-1069
Author(s):  
Bin Liu ◽  
Lin Wang ◽  
Yin Zhong Bu ◽  
Sheng Rong Yang ◽  
Jin Qing Wang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Attenuated Total Reflectance ◽  
Ti Alloy ◽  
Force Microscopy ◽  
Implant Materials ◽  
Atomic Force ◽  
Casein Phosphopeptides ◽  
Potential Applications ◽  
First Time

Titanium (Ti) and its alloys have been applied in orthopedics as one of the most popular biomedical metallic implant materials. In this work, to enhance the bioactivity, the surface of Ti alloy pre-modified by silane coupling agent and glutaraldehyde was covalently grafted with chitosan (CS) via biochemical multistep self-assembled method. Then, for the first time, the achieved surface was further immobilized with casein phosphopeptides (CPP), which are one group of bioactive peptides released from caseins in the digestive tract and can facilitate the calcium adsorption and usage, to form CS-CPP biocomposite coatings. The structure and composition of the fabricated coatings were characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and atomic force microscopy (AFM). As the experimental results indicated, multi-step assembly was successfully performed, and the CS and CPP were assembled onto the Ti alloy surface orderly. It is anticipated that the Ti alloys modified by CS-CPP biocomposite coatings will find potential applications as implant materials in biomedical fields.

Surface diagnostics for scale analysis

2004 ◽  
Vol 49 (2) ◽  
pp. 183-190 ◽  
Author(s):  
S. Dunn ◽  
S. Impey ◽  
C. Kimpton ◽  
S.A. Parsons ◽  
J. Doyle ◽  
...  
Keyword(s):  
Adhesion Force ◽  
Polymer Materials ◽  
Rapid Screening ◽  
Force Measurements ◽  
Energy Materials ◽  
Force Microscopy ◽  
Atomic Force ◽  
Surface Modified ◽  
Surface Diagnostics ◽  
Microscopy Techniques

Stainless steel, polymethylmethacrylate and polytetrafluoroethylene coupons were analysed for surface topographical and adhesion force characteristics using tapping mode atomic force microscopy and force-distance microscopy techniques. The two polymer materials were surface modified by polishing with silicon carbide papers of known grade. The struvite scaling rate was determined for each coupon and related to the data gained from the surface analysis. The scaling rate correlated well with adhesion force measurements indicating that lower energy materials scale at a lower rate. The techniques outlined in the paper provide a method for the rapid screening of materials in potential scaling applications.

scholarly journals Recent Applications of Advanced Atomic Force Microscopy in Polymer Science: A Review

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1142 ◽  
Author(s):  
Phuong Nguyen-Tri ◽  
Payman Ghassemi ◽  
Pascal Carriere ◽  
Sonil Nanda ◽  
Aymen Amine Assadi ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Chemical Characterization ◽  
Super Resolution ◽  
Polymeric Materials ◽  
Polymer Materials ◽  
Polymer Science ◽  
Force Microscopy ◽  
Atomic Force ◽  
Nanoscale Characterization

Atomic force microscopy (AFM) has been extensively used for the nanoscale characterization of polymeric materials. The coupling of AFM with infrared spectroscope (AFM-IR) provides another advantage to the chemical analyses and thus helps to shed light upon the study of polymers. This paper reviews some recent progress in the application of AFM and AFM-IR in polymer science. We describe the principle of AFM-IR and the recent improvements to enhance its resolution. We also discuss the latest progress in the use of AFM-IR as a super-resolution correlated scanned-probe infrared spectroscopy for the chemical characterization of polymer materials dealing with polymer composites, polymer blends, multilayers, and biopolymers. To highlight the advantages of AFM-IR, we report several results in studying the crystallization of both miscible and immiscible blends as well as polymer aging. Finally, we demonstrate how this novel technique can be used to determine phase separation, spherulitic structure, and crystallization mechanisms at nanoscales, which has never been achieved before. The review also discusses future trends in the use of AFM-IR in polymer materials, especially in polymer thin film investigation.

scholarly journals Dissipation signals due to lateral tip oscillations in FM-AFM

2014 ◽  
Vol 5 ◽  
pp. 2048-2057 ◽  
Author(s):  
Michael Klocke ◽  
Dietrich E Wolf
Keyword(s):  
Atomic Force Microscopy ◽  
Surface Energy ◽  
Unit Cell ◽  
Ionic Crystals ◽  
Force Microscopy ◽  
Normal Oscillation ◽  
Line Scan ◽  
Atomic Force ◽  
Dissipation Mechanism ◽  
Lateral Excitation

We study the coupling of lateral and normal tip oscillations and its effect on the imaging process of frequency-modulated dynamic atomic force microscopy. The coupling is induced by the interaction between tip and surface. Energy is transferred from the normal to the lateral excitation, which can be detected as damping of the cantilever oscillation. However, energy can be transferred back into the normal oscillation, if not dissipated by the usually uncontrolled mechanical damping of the lateral excitation. For certain cantilevers, this dissipation mechanism can lead to dissipation rates larger than 0.01 eV per period. The mechanism produces an atomic contrast for ionic crystals with two maxima per unit cell in a line scan.

Improvement of Hydrophilic Stability of Diamond-Like Carbon Films by O2/CF4 Plasma Post-Treatment

2015 ◽  
Vol 1125 ◽  
pp. 38-44
Author(s):  
Chavin Jongwannasiri ◽  
Shuichi Watanabe
Keyword(s):  
Carbon Films ◽  
Post Treatment ◽  
Attenuated Total Reflectance ◽  
Diamond Like Carbon ◽  
Total Reflectance ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements ◽  
Before And After

In this article, the results obtained from a study carried out on the plasma post-treatment of diamond-like carbon (DLC) films using an oxygen/tetrafluoromethane (O2/CF4) gas mixture is reported. The surface morphology and chemical bonding of the films before and after the plasma post-treatment were characterized using atomic force microscopy (AFM) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. The effect of adding CF4 to the O2 plasma on the wettability of the films was also examined using contact angle measurements. The results indicate that the surface roughness increased with the addition of CF4 to the O2 plasma, whereas oxygen-and fluorinated-based functional groups were generated on the surface of the DLC films submitted to O2/CF4 plasma post-treatment. The surface energy also decreased with increasing CF4 fraction, causing the surface of the films to be hydrophobic. Furthermore, the films containing 20% CF4 exhibited higher hydrophilic stability than the others. Thus, the addition of a small amount of CF4 to O2 plasma can be considered beneficial in improving the hydrophilic stability of surface of DLC films.

scholarly journals Electrochemical assessment of pigments-binding medium interactions in oil paint deterioration: a case study on indigo and Prussian blue

2020 ◽  
Author(s):  
Antonio Doménech-Carbó ◽  
María Teresa Doménech-Carbó ◽  
Laura Osete-Cortina ◽  
Margherita Donnici ◽  
Nuria Guasch-Ferré ◽  
...  
Keyword(s):  
Prussian Blue ◽  
Paint Film ◽  
Attenuated Total Reflectance ◽  
Radical Scavenger ◽  
Binding Medium ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Gas Chromatography Mass Spectroscopy

Abstract The degradation of laboratory oil paint film specimens containing indigo and Prussian blue pigments and pictorial samples from the Sant Francesc de Paula painting exhibited in the Tomàs Balvey Arxiu Museum (Cardedeu (Catalonia), Spain) has been studied by voltammetry of immobilized particles. This technique, combined with light microscopy, scanning electron microscopy-energy dispersive X-ray analysis, nanoindentation-atomic force microscopy, attenuated total reflectance-Fourier-transform infrared spectroscopy and gas chromatography-mass spectroscopy techniques permits the proposal of a dual scheme for the degradation of the pigments when naturally aged and submitted to accelerated UVA aging. Under conditions of moderate temperature, humidity and natural illumination, and low gradients of these parameters, Prussian blue acts as a radical scavenger moderating the production of reactive oxygen species produced in the oil binding medium by the action of ultraviolet radiation, resulting in the formation, in the solid state, of the solid-solution, {KFeIII[FeII(CN)6]}x{FeIII[FeIII(CN)6]}1–x, known as Berlin green, which then promotes the formation of indigo adducts with radicals. In several localized areas of the Sant Francesc de Paula paint showing strong degradation, Prussian blue acts as a promoter of the indigo oxidation to isatin, thus resulting in a considerable chromatic shift.

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