Optical, Electrical, Thermal and Chemical Properties

Perfluorocyclobutane (PFCB) polyaryl ethers are one such class of partially fluorinated polymers which combine the processability and durability of engineering thermoplastics with the optical, electrical, thermal, and chemical resistant properties of traditional fluoroplastics. Developed originally at The Dow Chemical Company" in Freeport, TX, PFCB polymers are prepared by the radical mediated thermal cyclopolymerization of trifluorovinyl ethers (Figure 1) and have, to date, provided a variety of thermoplastic and thermosetting materials possessing a tunable range of... 

Finally, for practical reasons it is useful to classify polymeric materials according to where and how they are employed. A common subdivision is that into structural polymers and functional polymers. Structural polymers are characterized by - and are used because of - their good mechanical, thermal, and chemical properties. Hence, they are primarily used as construction materials in addition to or in place of metals, ceramics, or wood in applications like plastics, fibers, films, elastomers, foams, paints, and adhesives. Functional polymers, in contrast, have completely different property profiles, for example, special electrical, optical, or biological properties. They can assume specific chemical or physical functions in devices for microelectronic, biomedical applications, analytics, synthesis, cosmetics, or hygiene. 

PPQs possess a stepladder stmcture that combines good thermal stabiUty, electrical insulation, and chemical resistance with good processing characteristics (81). These properties allow unique appHcations in the aerospace and electronics industries (82,83). PPQ can be made conductive by the use of an electrochemical oxidation method (84). The conductivities of these films vary from 10 to 10 S/cm depending on the dopant anions, thus finding appHcations in electronics industry. Similarly, some thermally stable PQs with low dielectric constants have been produced for microelectronic appHcations (85). Thin films of PQs have been used in nonlinear optical appHcations (86,87). 

Many of the chemical and physical properties of mineral fillers are important in their application in thermoplastics. These include purity, specific gravity, hardness, electrical, thermal and optical properties, surface area, particle shape and size. The determination and importance of many of these has been covered in several reviews [65,66]. Only a brief coverage is given here for the less ambiguous properties such as specific gravity, hardness and standard thermal and optical properties, with most attention being concentrated on properties such as size and shape which have been found to give particular problems in measurement and interpretation. 

Because of their electrical, optical, and redox properties as well as the thermal and chemical stability, the Pcs also have been tried in the detection of volatile organic compounds and poisonous gases, which is very important for environment and human health. In the past decades, the possible applications of Pc thin film as sensor for atmospheric gaseous pollutants have been extensively studied [73, 74], Langmuir-Blodgett films of some multinuclear and multidouble-decker lutetium Pcs have also been used for those measurements [75,76], More details about conductivity and sensing properties of Pcs can be found elsewhere [77,78]. 

Perfluorinated dioxole monomers have been used to prepare a series of amorphous fluoropolymers such as Teflon AF and Hyflon AD. A third amorphous fluoropo-lymer, Cytop contains perfluorotetrahydrofuran and perfluorotetrahydropyran rings, but is prepared in a cyclopolymerization process from an acyclic monomer. These amorphous fluoropolymers retain the outstanding chemical, thermal, and surface properties associated with perfluorinated polymers while also having unique electrical, optical, and solubility characteristics. 

Core-shell particles have attracted much research attention in recent years because of their great potential in the protection, modification, and functionalization of the core with suitable shell materials to achieve specific physical or chemical performances. For instance, the optical, electrical, thermal, mechanical, magnetic, and catalytic properties of core particles can be finely tuned by coating them with a thin mineral shell [73, 74]. Silica shells are produced by a variety of methods that can be divided into two groups (1) the layer-by-layer self-assembly of preformed silica nanoparticles on oppositely charged templates, and (2) seeded polycondensation techniques involving sol-gel precursors. The former method is outside the scope of this article and only the second method will be discussed. 

This chapter presents an overview of properties and performance of polymer blends. It is structured into nine sections dealing with aspects required for assessing the performance of a polymer blend. These are mechanical properties comprising of both low-speed and high-speed popularly studied properties chemical and solvent effects thermal and thermodynamic properties flammability electrical, optical, and sound transmission properties and some special test methods which assumed prominence recently because of their utility. 

In biomedical research, carbon nanomaterials (CNMs) are considered to be the most attractive materials since they possess distinctive physical and chemical properties such as excellent mechanical strength, electrical and thermal conductivity, and optical properties... 

Carbon (element No. 6 in the periodic table) forms a variety of materials, including graphite, diamond, carbon fibers, charcoal, as well as newly discovered nanocarbon materials, such as fullerene, graphene, carbon nanotube, and graphene nanoribbon (GNR). Even though all are composed of the same atoms, different carbon materials can show very different physical and chemical properties, including electrical transport, optical and thermal properties, and chemical reactivity, depending on their structures. 

Among various strategies that have been used to synthesize polyimides with lower dielectric constants, the most common approach is to incorporate fluorene, in the form of trifluoromethyl groups, into diamine and dianhydride units that minimize polarizability and increase the free volume [46]. It is well-known that fluorene atom has unique characteristics such as high electronegativity and low electric polarity. These properties give fluorinated polymers (e.g., poly[tetrafluoroethylene]) attractive features such as low water uptake, water and oil repellency, low permittivity, low refractive indices, resistance to wear and abrasion, and thermal and chemical stability. Fluorination is also known to enhance solubility and optical transparency and to lower the moisture absorption of polyimides. Therefore, it is expected that fluorinated polyimides will be widely applied in the electro-optical and semiconductor industries. The polymer series studied was essentially limited mainly to 6F dianhydride because it proved to be the only dianhydride with which many of the fluorinated diamines would form polymer films suitable for physical characterization. 

Copolymers of tetrafluoroethylene and 2,2-bistrifluoromethyl-4,5-difluoro-1,3-dioxole (PDD) are perfluorinated amorphous polymers and possess unusual combination of properties. They retain the outstanding chemical, thermal, and surface properties of perfluorinated polymers in addition to having excellent electrical and optical properties and have solubility at ambient temperature in a normal fluorosolvent. This family of copolymers is manufactured by DuPont and sold under the trade name of Teflon AF, amorphous fluoropolymers. 

The material has a lot of stmctural polytypes. The silicon carbide atoms are in state of sp3-hybridization and form a bond of a tetrahedron. In the crystal lattice of silicon carbide the short-range order is always the same but the long-range can differ that is why there are many polytypes of this material. The stmetural difference causes difference in physical and chemical properties (e.g., thermal resistance, electrical and optical characteristics). It makes one or another polytype being more preferred for different application. 

Shah, V. 2007. Handbook of Plastics Testing and Failure Analysis, 3rd ed. New York John Wiley Sons. Six chapters are devoted to mechanical, thermal, electrical, weathering, optical, and chemical properties, and respective testing. The remainder of the book deals with other plastic testing issues and techniques. Includes tables, illustrations, and extensive references. Available online on Wiley Online Library. 

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