Polymer based functional materials: A new generation photo‐active candidate for electrochemical application

2021 ◽  
Author(s):  
Abhisek Ghosh ◽  
Sayan Basak ◽  
Abhijit Bandyopadhyay
2000 ◽  
Author(s):  
Jeff W. McCutcheon

Abstract The key to successful multifunctional materials applications for vibration, shock and acoustic control is often the proper selection of materials, geometric design and optimum application. Much work has been done in the areas of geometric designs and optimum application of the multi-functional materials. The next step is improvements in the passive damping materials themselves. The improvement in the passive materials in the past has often focused on the areas of improved damping performance (loss factor, storage modulus), material performance (acrylics, silicones, etc.) and enhanced features (thermally conductive, electrically conductive, etc). One of the newest requirements for passive damping polymers is in the area of ultra-pure viscoelastic damping polymers. This new generation of materials is finding growing use because the sensitive environment where the passive material is used require a material that will not negatively impact the components in that environment. This new generation of passive materials needs to be ultra-pure with respect to organic material outgassing, anions, catalysts and siloxanes. In addition to the viscoelastic damping polymer requirements for high purity, the associated polymeric materials (epoxies, laminating adhesives and tapes) used in the same environment must also be of a similar low outgassing, ultra-pure, ultra-clean, electronics grade or clean room performance designation. If this is not done, the environment could become contaminated and negate a portion of the benefit of using the clean damping material. This also requires an understanding of the test method used to determine each product’s cleanliness performance, as all test methods are not equal and can give significantly different test results. An example is comparing a polymer sample tested for organic outgassing and using a static headspace gas chromatography/mass spectroscopy (GC/MS) and a dynamic headspace GC/MS.


2020 ◽  
Vol 73 (7) ◽  
pp. 587
Author(s):  
Sitong Guo ◽  
Wen Tan ◽  
Jiyicheng Qiu ◽  
Jinlong Du ◽  
Zhanxu Yang ◽  
...  

As a popular material synthesis method, spatially confined reactions have been gradually recognised for their excellent performance in the field of current materials synthesis. In recent years, molybdenum-based catalysts have gradually gained recognition due to high natural reserves of Mo, its low cost, and many other advantages, and they have wide applications in the area of functional materials, especially in topical areas such as batteries and electrocatalysts. In this context, spatially confined reactions have become widely to obtain various types of molybdenum-based electrode materials and electrocatalysts which result in an excellent morphology, structure, and performance. In this review, the concept of a spatially confined reaction system and the electrochemical application (electrode materials and electrocatalyst) of molybdenum-based materials synthesised in this way are comprehensively discussed. The current problems and future development and application of molybdenum-based materials are also discussed in this review.


2021 ◽  
Vol 15 ◽  
pp. 204-210
Author(s):  
A. Yu. Ershova ◽  
Minggong Sha

n this work, we studied the properties of a specially synthesized organometallic coordination polymer - a porous coordination polymer with biocompatible structural elements based on oxoclusters of iron muconate (III). The samples were investigated by scanning electron microscopy, thermogravimetric analysis combined with differential scanning calorimetry, and the study of low-temperature nitrogen adsorption of a sample obtained by a modified solvothermal technique. It is shown that most of the pores of the sample have an average radius of 18,8 Å ~ 1,88 nm. Also, as a result of the study, it is necessary to conclude that the synthesized material has a developed surface area - it is 512,1 m2/g and the pore volume is ~ 0,48 cm3/g. It should be concluded that such materials are promising as components for a new generation of various kinds of functional materials with improved or unique characteristics. It is obvious that further research in this area is important from both fundamental and applied points of view.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Samy A. Madbouly

Abstract Polyhydroxyalkanoates (PHAs) are linear semicrystalline polyesters produced naturally by a wide range of microorganisms for carbon and energy storage. PHAs can be used as replacements for petroleum-based polyethylene (PE) and polypropylene (PP) in many industrial applications due to their biodegradability, excellent barrier, mechanical, and thermal properties. The overall industrial applications of PHAs are still very limited due to the high production cost and high stiffness and brittleness. Therefore, new novel cost-effective production method must be considered for the new generation of PHAs. One approach is based on using different type feedstocks and biowastes including food byproducts and industrial and manufacturing wastes, can lead to more competitive and cost-effective PHAs products. Modification of PHAs with different function groups such as carboxylic, hydroxyl, amine, epoxy, etc. is also a relatively new approach to create new functional materials with different industrial applications. In addition, blending PHA with biodegradable materials such as polylactide (PLA), poly(ε-caprolactone) (PCL), starch, and distiller’s dried grains with solubles (DDGS) is another approach to address the drawbacks of PHAs and will be summarized in this chapter. A series of compatibilizers with different architectures were successfully synthesized and used to improve the compatibility and interfacial adhesion between PHAs and PCL. Finer morphology and significantly improvement in the mechanical properties of PHA/PCL blends were observed with a certain type of block compatibilizer. In addition, the improvement in the blend morphology and mechanical properties were found to be strongly influenced by the compatibilizer architecture.


Medicines ◽  
2020 ◽  
Vol 7 (9) ◽  
pp. 49
Author(s):  
Charnete Casimero ◽  
Todd Ruddock ◽  
Catherine Hegarty ◽  
Robert Barber ◽  
Amy Devine ◽  
...  

Catheter related blood stream infection is an ever present hazard for those patients requiring venous access and particularly for those requiring long term medication. The implementation of more rigorous care bundles and greater adherence to aseptic techniques have yielded substantial reductions in infection rates but the latter is still far from acceptable and continues to place a heavy burden on patients and healthcare providers. While advances in engineering design and the arrival of functional materials hold considerable promise for the development of a new generation of catheters, many challenges remain. The aim of this review is to identify the issues that presently impact catheter performance and provide a critical evaluation of the design considerations that are emerging in the pursuit of these new catheter systems.


Author(s):  
D. Cherns

The use of high resolution electron microscopy (HREM) to determine the atomic structure of grain boundaries and interfaces is a topic of great current interest. Grain boundary structure has been considered for many years as central to an understanding of the mechanical and transport properties of materials. Some more recent attention has focussed on the atomic structures of metalsemiconductor interfaces which are believed to control electrical properties of contacts. The atomic structures of interfaces in semiconductor or metal multilayers is an area of growing interest for understanding the unusual electrical or mechanical properties which these new materials possess. However, although the point-to-point resolutions of currently available HREMs, ∼2-3Å, appear sufficient to solve many of these problems, few atomic models of grain boundaries and interfaces have been derived. Moreover, with a new generation of 300-400kV instruments promising resolutions in the 1.6-2.0 Å range, and resolutions better than 1.5Å expected from specialist instruments, it is an appropriate time to consider the usefulness of HREM for interface studies.


Author(s):  
Jorge Perdigao

In 1955, Buonocore introduced the etching of enamel with phosphoric acid. Bonding to enamel was created by mechanical interlocking of resin tags with enamel prisms. Enamel is an inert tissue whose main component is hydroxyapatite (98% by weight). Conversely, dentin is a wet living tissue crossed by tubules containing cellular extensions of the dental pulp. Dentin consists of 18% of organic material, primarily collagen. Several generations of dentin bonding systems (DBS) have been studied in the last 20 years. The dentin bond strengths associated with these DBS have been constantly lower than the enamel bond strengths. Recently, a new generation of DBS has been described. They are applied in three steps: an acid agent on enamel and dentin (total etch technique), two mixed primers and a bonding agent based on a methacrylate resin. They are supposed to bond composite resin to wet dentin through dentin organic component, forming a peculiar blended structure that is part tooth and part resin: the hybrid layer.


Author(s):  
S. J. Krause ◽  
W.W. Adams ◽  
S. Kumar ◽  
T. Reilly ◽  
T. Suziki

Scanning electron microscopy (SEM) of polymers at routine operating voltages of 15 to 25 keV can lead to beam damage and sample image distortion due to charging. Imaging polymer samples with low accelerating voltages (0.1 to 2.0 keV), at or near the “crossover point”, can reduce beam damage, eliminate charging, and improve contrast of surface detail. However, at low voltage, beam brightness is reduced and image resolution is degraded due to chromatic aberration. A new generation of instruments has improved brightness at low voltages, but a typical SEM with a tungsten hairpin filament will have a resolution limit of about 100nm at 1keV. Recently, a new field emission gun (FEG) SEM, the Hitachi S900, was introduced with a reported resolution of 0.8nm at 30keV and 5nm at 1keV. In this research we are reporting the results of imaging coated and uncoated polymer samples at accelerating voltages between 1keV and 30keV in a tungsten hairpin SEM and in the Hitachi S900 FEG SEM.


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