Polyacrylonitrile silicone

Particle conductivity has a strong influence on ER performance. Block [24J studied how ER effect is influenced by the particle conductivity using the acene-quinone radical polymer/silicone oil, and found that the static yield stress peaks at a particle conductivity around 10 S/m (sec Figure 17). The molecular structure of the acene-quinone radical polymers is shown in Figure 18 and Figure 3 in Chapter 3. A similar tendency was found in oxidized polyacrylonitrile/silicone oil ER system [61J. However, the yield Stress peaks at the particle conductivity of about 10 S/m, rather than 10 ... 

Figure 46 Complex viscosity of oxidized polyacrylonitrile/silicone oil suspension vs. the particle volume fraction at different electric fields. The mechanical strain is 1 and frequency is 5 s. Reproduced with permission from Y. Xu, R. Liang, J. Rheol. 35 (1991) 1355.

Figure 11 The real modulus and complex viscosity vs. the particle volume fraction for oxidi/.ed polyacrylonitrile/silicone oil suspensions. The applied electric field = 1.5 kV/mm. The strain amplitude = 200%, frequency = 2 Hz. Redrawn with permission from T. Hao, Y. Chen, Z. Xu, Y. Xu and Y. Huang, Chin. J. Polym. Sci., 12(1994)97...

Figure 51 The de current against time obtained at 2,0 kV/mm for oxidized polyacrylonitrile/silicone oil suspension. Particle volume fraction is 27 vol%. Reproduced with permission from T. Hao, and Y. Xu, J. Colloid Interf. Sci., 181(1996)581...

Organs Polyurethane, cellulose, silicone-collagen composites, polyacrylonitrile, silicone rubber, polysuphone, titanium... 

Tetraethylene glycol may be used direcdy as a plasticizer or modified by esterification with fatty acids to produce plasticizers (qv). Tetraethylene glycol is used direcdy to plasticize separation membranes, such as silicone mbber, poly(vinyl acetate), and cellulose triacetate. Ceramic materials utilize tetraethylene glycol as plasticizing agents in resistant refractory plastics and molded ceramics. It is also employed to improve the physical properties of cyanoacrylate and polyacrylonitrile adhesives, and is chemically modified to form polyisocyanate, polymethacrylate, and to contain silicone compounds used for adhesives. 

RUBBER (Synthetic). Any of a group of manufactured elastomers that approximate one or more of the properties of natural rubber. Some of these aie sodium polysulfide ( Thiokol ). polychloiopiene (neoprene), butadiene-styrene copolymers (SBR), acrylonitrilebutadiene copolymers (nitril rubber), ethvlenepropylene-diene (EPDM) rubbers, synthetic poly-isoprene ( Coral, Natsyn ), butyl rubber (copolymer of isobutylene and isoprene), polyacrylonitrile ( Hycar ). silicone (polysiloranei. epichlorohy-drin, polyurethane ( Vulkollan ). 

Membranes comprising silicone rubber coated onto polyimides, polyacrylonitrile or other microporous supports membranes are widely used [12,27]. Other rubbers such as ethylene-propylene terpolymers have been reported to have good properties also [28]. Polyamide-polyether block copolymers have also been used for pervaporation of some polar VOCs [29,30]... 

Organ replacement Heart-lung machine Artificial kidney (hemodialyzer) Artificial heart Silicone rubber Cellulose, polyacrylonitrile Polyurethane... 

Porous membranes can be made of polymers (polysulfones, polyacrylonitrile, polypropylene, silicones, perfluoropolymers, polyimides, polyamides, etc.), ceramics (alumina, silica, titania, zirconia, zeolites, etc.) or microporous carbons. Dense organic membranes are commonly used for molecular-scale separations involving gas and vapor mixtures, whereas the mean pore sizes of porous membranes is chosen considering the size of the species to be separated. Current membrane processes include microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), gas and vapor separation (GS), and pervaporation (PV). Figure 1 indicates the types and sizes of species typically separated by these different separation processes. 

Carbon-carbon composites can be produced with a multitude of structures. The simplest have two-dimensional order and consist of stacked plies of carbon fabric held together by a carbon matrix. The fabric fibers may be any of those described previously, prepared from the pyrolysis of polyacrylonitrile and the like. The matrix could be derived from petroleum pitch or be infiltrated pyrolytic carbon or even silicon carbide. The latter are generally referred to as SiC/C composites. From two-dimensional, the next progression in structure is three-dimensional on to n-dimensional. This terminology refers to fiber orientation within the matrix. 

These requirements may be satisfied by selecting an appropriate structure and type of fiber for the filter fabric, and by surface treatment. Up until recently, woven cotton, wool fabrics, and felted materials were used extensively in industrial filters. Today, synthetic materials are coming into use. For example, a glass fabric treated with silicones is a good filter material at temperatures of 150-315°C. At lower temperatures (below 150°C), filter fabric materials may be made of Lavsan, Nitron, Kapron, or Khlorin (polyester, polyacrylonitrile, polyamide, and chlorinated PVC fibers, respectively). 

Thakur M, Pemites RB, Nitta N, Isaacson M, Sinsabaugh SL, Wong MS, Biswal SL (2012) Freestanding macroporous silicon and pyrolyzed polyacrylonitrile as a composite anode for lithium ion batteries. Chem Mat 24 2998-3003... 

Some applications require cheap electroconductive material based on small silicon particulates of high surface area. Authors of paper (Thakur et al. 2012) report on ultrasonically fiuctured macroporous membranes, mixing silicon particulates (size range 10-50 pm) with pyrolyzed polyacrylonitrile and application of the mixture for produeing long life anodes of lithium ion batteries. 

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