The influence of organosoluble (co)polyimides side functionalization and drawing parameters on the optical fibre coatings formation and properties

2017 ◽  
Vol 29 (6) ◽  
pp. 663-669 ◽  
Author(s):  
Dmitry A Sapozhnikov ◽  
Bato A Bayminov ◽  
Olesya N Zabegaeva ◽  
Diana D Alexeeva ◽  
Sergey L Semjonov ◽  
...  
Keyword(s):  
Optical Fibre ◽  
Bending Strength ◽  
High Thermal Stability ◽  
Carboxyl Groups ◽  
Technological Parameters ◽  
Good Adhesion ◽  
Coating Quality ◽  
Temperature Method ◽  
One Step ◽  
Additional Coupling

A series of the copolyimides have been synthesized by one-step high-temperature method in m-cresol solution to explore their effect on the optical fibre coatings formation and properties. The following parameters that influence the coating quality and properties have been estimated: the viscosity of the polymer solution, drawing technological parameters, polyimide (PI) structure and molecular weight. It was found that copolyimides bearing side hydroxyl and carboxyl groups formulate the coatings with good adhesion without additional coupling agent. The fibres with elaborated PI coatings have high thermal stability. For some of them, 20% reduction of the fibre’s bending strength takes place only after heating for 24–72 h at 300°C.

scholarly journals Chlorine-Functional Silsesquioxanes (POSS-Cl) as Effective Flame Retardants and Reinforcing Additives for Rigid Polyurethane Foams

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3979
Author(s):  
Anna Strąkowska ◽  
Sylwia Członka ◽  
Karolina Miedzińska ◽  
Krzysztof Strzelec
Keyword(s):  
Flame Retardants ◽  
Elevated Temperatures ◽  
Bending Strength ◽  
Reaction System ◽  
Fire Retardant ◽  
Polyurethane Foams ◽  
Polymerization Reaction ◽  
Three Point Bending ◽  
One Step

The subject of the research was the production of silsesquioxane modified rigid polyurethane (PUR) foams (POSS-Cl) with chlorine functional groups (chlorobenzyl, chloropropyl, chlorobenzylethyl) characterized by reduced flammability. The foams were prepared in a one-step additive polymerization reaction of isocyanates with polyols, and the POSS modifier was added to the reaction system in an amount of 2 wt.% polyol. The influence of POSS was analyzed by performing a series of tests, such as determination of the kinetics of foam growth, determination of apparent density, and structure analysis. Compressive strength, three-point bending strength, hardness, and shape stability at reduced and elevated temperatures were tested, and the hydrophobicity of the surface was determined. The most important measurement was the determination of the thermal stability (TGA) and the flammability of the modified systems using a cone calorimeter. The obtained results, after comparing with the results for unmodified foam, showed a large influence of POSS modifiers on the functional properties, especially thermal and fire-retardant, of the obtained PUR-POSS-Cl systems.

Succinate Functionalization of Hyperbranched Polyglycerol-Coated Magnetic Nanoparticles as a Draw Solute During Forward Osmosis

2015 ◽  
Vol 15 (10) ◽  
pp. 8279-8284 ◽  
Author(s):  
Hee-Man Yang ◽  
Hye Min Choi ◽  
Sung-Chan Jang ◽  
Myeong Jin Han ◽  
Bum-Kyoung Seo ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Succinic Anhydride ◽  
Water Flux ◽  
Forward Osmosis ◽  
Feed Solution ◽  
Carboxyl Groups ◽  
Solute Leakage ◽  
One Step ◽  
Hyperbranched Polyglycerol ◽  
The One

Hyperbranched polyglycerol-coated magnetic nanoparticles (SHPG-MNPs) were functionalized with succinate groups to form a draw solute for use in a forward osmosis (FO). After the one-step synthesis of hyperbranched polyglycerol-coated magnetic nanoparticles (HPG-MNPs), the polyglycerol groups on the surfaces of the HPG-MNPs were functionalized with succinic anhydride moieties. The resulting SHPG-MNPs showed no change of size and magnetic property compared with HPGMNPs and displayed excellent dispersibility in water up to the concentration of 400 g/L. SHPG-MNPs solution showed higher osmotic pressure than that of HPG-MNPs solution due to the presence of surface carboxyl groups in SHPG-MNPs and could draw water from a feed solution across an FO membrane without any reverse draw solute leakage during FO process. Moreover, the water flux remained nearly constant over several SHPG-MNP darw solute regeneration cycles applied to the ultrafiltration (UF) process. The SHPG-MNPs demonstrate strong potential for use as a draw solute in FO processes.

scholarly journals TEMPO-Functionalized Nanoporous Au Nanocomposite for the Electrochemical Detection of H2O2

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Dongxiao Wen ◽  
Qianrui Liu ◽  
Ying Cui ◽  
Huaixia Yang ◽  
Jinming Kong
Keyword(s):  
Electrochemical Detection ◽  
Nanoporous Gold ◽  
Carboxyl Groups ◽  
Time Interval ◽  
Optimal Conditions ◽  
Sem Images ◽  
One Step ◽  
Ph Range ◽  
Synthesis Approach ◽  
Higher Sensitivity

A novel nanocomposite of nanoporous gold nanoparticles (np-AuNPs) functionalized with 2,2,6,6-tetramethyl-1-piperidinyloxy radical (TEMPO) was prepared; assembled carboxyl groups on gold nanoporous nanoparticles surface were combined with TEMPO by the “bridge” of carboxylate-zirconium-carboxylate chemistry. SEM images and UV-Vis spectroscopies of np-AuNPs indicated that a safe, sustainable, and simplified one-step dealloying synthesis approach is successful. The TEMPO-np-AuNPs exhibited a good performance for the electrochemical detection of H2O2 due to its higher number of electrochemical activity sites and surface area of 7.49 m2g-1 for load bigger amount of TEMPO radicals. The TEMPO-functionalized np-AuNPs have a broad pH range and shorter response time for H2O2 catalysis verified by the response of amperometric signal under different pH and time interval. A wide linear range with a detection limit of 7.8 × 10-7 M and a higher sensitivity of 110.403 μA mM-1cm-2 were obtained for detecting H2O2 at optimal conditions.

Electroplating of Indium-Cadmium and Tin-Cadmium Alloy Coatings

2022 ◽  
Vol 1049 ◽  
pp. 124-129
Author(s):  
Sergey Yu. Kireev ◽  
Svetlana N. Kireeva ◽  
Anatoly Frolov ◽  
Alfiya Yangurazova ◽  
Konstantin Anopin
Keyword(s):  
Protective Coatings ◽  
Machine Building ◽  
Corrosion And Wear ◽  
Electric Resistance ◽  
Technological Parameters ◽  
Good Adhesion ◽  
Instrument Making ◽  
Building Products ◽  
Climatic Testing ◽  
Marine Climate

Technological parameters for electroplating cadmium alloy (Cd (24)-In and Cd (33)-Sn) coatings from low toxic solutions have been proposed. Since the fabricated alloy coatings possess low internal stress and microhardness, good adhesion property, high corrosion and wear resistance, they can be used as protective coatings for machine building products to enhance reliability and operability thereof. The presence of good solderability and low values of transient electric resistance in climatic testing favor these coatings to be applied in hetero-structured contact systems of instrument making products for increasing their reliability and operability in a tropical marine climate.

One-step purification of a recombinant beta-galactosidase using magnetic cellulose as a support: Rapid immobilization and high thermal stability

2021 ◽  
pp. 126497
Author(s):  
Adriano Gennari ◽  
Renate Simon ◽  
Nathalia Denise de Moura Sperotto ◽  
Cristiano Valim Bizarro ◽  
Luiz Augusto Basso ◽  
...  
Keyword(s):  
Thermal Stability ◽  
High Thermal Stability ◽  
One Step ◽  
Beta Galactosidase

Determination Compressive and Bending Strength of Porous Bodies from Plaster Reinforced with Polyacetate of Vinila (PVAc)

2019 ◽  
Vol 958 ◽  
pp. 53-56
Author(s):  
Aoliabe Pedro da Silva ◽  
Laudir de Castro Ferreira Neto ◽  
Nelson Cárdenas Olivier ◽  
Alessandra Félix da Costa Pereira ◽  
Alan Christie da Silva Dantas
Keyword(s):  
Mechanical Properties ◽  
Calcium Sulfate ◽  
Polyvinyl Acetate ◽  
Bending Strength ◽  
Low Cost ◽  
Building Industry ◽  
Good Adhesion ◽  
Porous Bodies ◽  
Interesting Alternative ◽  
Technological Interest

Calcium sulfate dehydrate β (CaSO4. 0,5H2O) is a material obtained from the calcination of gypsite (CaSO4.2H2O). This is a low cost ceramic material very used in building industry. The improvement of their applications is of fundamental technological interest. Polymers are an interesting alternative of reinforcement. Polyvinyl acetate (PVAc) is an addition polymer obtained by the polymerization of vinyl acetate. This polymer is well known to achieve good adhesion to cellulosic surfaces. The aim of this work was to evaluate the mechanical properties of porous plaster bodies reinforced with PVAc. Mechanical behavior was characterized by compression and bending strength. Three water / gypsum ratios: 0.5 0.6 and 0.7 were used on this work. An amount of 5% and 10% PVAc promoted increase on the mechanical properties of gypsum. Higher amounts polymer promoted further decrease of the mechanical properties.

Ta2O5 Nanobars and Their Composites: Synthesis and Characterization

2008 ◽  
Vol 8 (11) ◽  
pp. 5801-5806 ◽  
Author(s):  
P. P. George ◽  
A. Gedanken
Keyword(s):  
Electron Microscopy ◽  
Absorption Spectrometry ◽  
Optical Devices ◽  
Band Gaps ◽  
Synthesis And Characterization ◽  
Carbon Spheres ◽  
Transmission Electron ◽  
Temperature Method ◽  
One Step ◽  
Promising Application

Novel Ta2O5 nanobars anchored on micron-sized carbon spheres were synthesized by the thermal decomposition of pentaethoxy tantalate, Ta(OEt)5. This one-step reaction was carried out using the RAPET (Reaction Under Autogenic Pressure at Elevated Temperature) method by dissociating Ta(OEt)5 at 800 °C for 3 h. The as-prepared Ta2O5/C nanobar-composite was annealed under air at 500 °C for 3 h (eliminating the carbon spheres), resulting in neat Ta2O5 nanobars. The products, Ta2O5/C and Ta2O5 nanobars, were characterized using methods such as electron microscopy (SEM, TEM, HRTEM, SAEDS, EA, EDX) and Powder-XRD. Transmission electron microscope (TEM) images indicated the particle size of the Ta2O5 nanobars coated on 40–60 nm carbon spheres. The optical properties of the Ta2O5/C nanobar-composite and the neat Ta2O5 nanobars were determined by UV-vis absorption spectrometry and their band gaps were found at 265 (4.7 eV) and 260 nm (4.8 eV), respectively. A PL band was also observed for a Ta2O5/C nanobar-composite and Ta2O5 nanobars. The above results indicate that Ta2O5 nanobars have a promising application in optical devices.

Joining of SiC Ceramic by High Temperature Brazing Using Ni-Cr-SiC Powders as Filler

2007 ◽  
Vol 336-338 ◽  
pp. 2394-2397
Author(s):  
Shu Jie Li ◽  
Yang Wu Mao ◽  
Yue Hui He
Keyword(s):  
High Temperature ◽  
Bending Strength ◽  
Weld Zone ◽  
Base Material ◽  
Product Layer ◽  
Weld Strength ◽  
Technological Parameters ◽  
Major Phase ◽  
Sic Ceramic ◽  
Filler Mass

Joining of ceramics is of importance from both technical and economical points of view. Brazing is a widely used process to join ceramics. In order to increase the working temperature and weld strength of joints, a high temperature brazing process using Ni-Cr-SiC powders (consisting of Ni, Cr and SiC powders) as filler to join recrystallized SiC ceramic has been investigated. The obtained optimized technological parameters are joining temperature of 1360°C, holding time of 5min and filler mass of 280mg. Under these conditions the maximum relative bending strength of joints, 70.5%, is achieved. Microstructure and phase analysis reveals that interdiffusions and chemical reactions take place in the weld zone. A reaction layer, of which the major phase is Ni2Si, exists between the welding base material SiC ceramic and the filler reaction product layer, called as interlayer, of which the major phase is Cr23C6.

Physiomechanical properties of ultra-lightweight foam core particleboard: different core densities

Holzforschung ◽  
2013 ◽  
Vol 67 (2) ◽  
pp. 169-175 ◽  
Author(s):  
Ali Shalbafan ◽  
Jan Luedtke ◽  
Johannes Welling ◽  
Arno Fruehwald
Keyword(s):  
Bending Strength ◽  
Core Layer ◽  
Strength Properties ◽  
Positive Influence ◽  
Foam Core ◽  
Press Temperature ◽  
Mechanical And Physical Properties ◽  
Wood Particles ◽  
One Step ◽  
Lightweight Foam

Abstract Ultra-lightweight foam core particleboards have been produced in a novel one-step process with resinated wood particles for the faces and expandable polystyrene (EPS) as core layer material. The mechanical and physical properties of panels were investigated in terms of the different foam core densities and press parameters (temperature, pressing and foaming time). The bending strength properties of the panels were not significantly changed with increasing foam core density from 80 to 120 kg m-3. Panels produced at a press temperature of 130°C (1-EPS) have an improved core-face interface and also a denser surface layer, which positively influences the internal bond and thickness swelling. The panels produced at a press temperature of 160°C (2-EPS) have smaller and more foam cells and an improved fusion of foam beads and properties, which have a positive influence on the edge screw withdrawal resistance and water absorption.

Sign in / Sign up

Export Citation Format

Share Document