Filling modification properties

The original basic fluorocarbon, and perhaps the most widely known one, is tetrafluo-roethylene (TFE). It has the optimum electrical and thermal properties and almost complete moisture resistance and chemical inertness. However, TFE does cold-flow or creep at moderate loading and temperatures. Filled modifications of TFE resins are available these are generally stronger than unfilled resins. Fluorinated ethylenepropylene (FEP) is similar to TFE except that its operating temperature is limited to 200°C. FEP is more easily processed,... 

With the development of filling modification technology and a deepening understanding of fillers, reasons for using them, especially the functional fillers, have expanded from pure cost reduction to a provision of some performance characteristics to products, such as electrical property, magnetism, electric wave absorbency, ultraviolet resistance, antibiosis, and other special... 

The properties of fillers such as geometric shape, particle size and distribution, physical and chemical properties, and so on will directly affect the material performances of the filling modification system. Fillers are classified mainly into the following kinds. 

The growth rate in the use of particulate filled polymers, including those prepared from polyolefins, is very rapid in all fields of application [1], Household articles, automotive parts and various other items are equally prepared from them. In the early days mostly particulate fillers were introduced into polymers and the sole reason for their application was to decrease cost. However, as a result of filling, all properties of the polymer change in fact a new polymer is created. Some characteristics improve, while others deteriorate, so properties must be optimized to utilize all the potentials of modification. Optimization must include all the factors infiuencing properties from component characteristics through structure to interactions. 

Modifications of the conduction properties of semiconducting carbon nanotubes by B (p-type) and N ( -type) substitutional doping has also been dis-cussed[3l] and, in addition, electronic modifications by filling the capillaries of the tubes have also been proposed[32]. Exohedral doping of the space between nanotubes in a tubule bundle could provide yet an-... 

Next, let us look at modification of CNTs. There are many approaches to modifying the electronic structure of CNTs oxidation [39], doping (intercalation) [69], filling [70] and substitution by hetero elements like boron and nitrogen atoms [71,72]. There have been few studies on the application of these CNTs but it will be interesting to study applications as well as electronic properties. 

However, the chief purpose of introduction of fillers into PCM is to make possible the modification of polymers and thereby create materials with a prescribed set of physico-mechanical properties, and, obviously, the properties of filled materials may be controlled by, for example, varying the type of the base polymer (the matrix ) and filler, its particle size distribution and shape. It may not require a large quantity of filler [7]. Thanks to considerable advances in PCM research, their use in a broad range of industries — machine building, construction, aerospace technology, etc. — has become extensive [8 — 11]. 

Fluoroelastomers Novikova et al. [32] reported unproved physico-mechanical properties of fluoro mbbers by reinforcement with chopped polyamide fibers. Other fiber reinforcements are covered by Grinblat et al. [33]. Watson and Francis [34] described the use of aramid (Kevlar) as short fiber reinforcement for vulcanized fluoroelastomer along with polychloroprene mbber and a co-polyester TPE in terms of improvement in the wear properties of the composites. Rubber diaphragms, made up of fluorosilicone mbbers, can be reinforced using aramid fiber in order to impart better mechanical properties to the composite, though surface modification of the fiber is needed to improve the adhesion between fluorosUicone mbber and the fiber [35]. Bhattacharya et al. [36] studied the crack growth resistance of fluoroelastomer vulcanizates filled with Kevlar fiber. 

In the last 10 years, CNTs are successfully functionalized via end terminal or sidewall modification or filling with biomolecules, or conjugating with polymers the resulting biomolecules-CNTs nanocomposites own special properties such as optimized mechanical, optical, electronic, and magnetic, and have great potential application in industry, agriculture, defense, and bio-medicine. Effects of CNTs on the cells, human health, and environment also attract more and more attention CNTs potential hazards... 

This chapter focuses its attention on the discussion of the most relevant questions of interfacial adhesion and its modification in particulate filled polymers. However, because of the reasons mentioned in the previous paragraph, the four factors determining the properties of particulate filled polymers will be discussed in the first section. Interactions can be divided into two groups, parti-cle/particle and matrix/filler interactions. The first is often neglected although it may determine the properties of the composite and often the only reason for surface modification is to hinder its occurrence. Similarly important, but a very contradictory question is the formation and properties of the interphase a separate section will address this question. The importance of interfacial adhesion... 

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