ORGANOSILICONE POLYMER

Organosilicon polymers. Silicon resembles carbon in certain respects and attempts have been made to prepare polymers combining carbon and silicon units in the molecule with the object of increasing the heat resistance of polymers. It has been found that the hydrolysis of a dialkyl-dichlorosilicane or an alkyltrichlorosilicane, or a mixture of the two, leads to polymers (Silicones), both solid and liquid, which possess great thermal stability. Thus dimethyldichlorosilicane (I) is rapidly converted by water into the silicol (II), which immediately loses water to give a silicone oil of the type (III) ... 

Gas-filled plastics are polymer materials — disperse systems of the solid-gas type. They are usually divided into foam plastics (which contain mostly closed pores and cells) and porous plastics (which contain mostly open communicating pores). Depending on elasticity, gas-filled plastics are conventionally classified into rigid, semi-rigid, and elastic, categories. In principle, they can be synthesized on the basis of any polymer the most widely used materials are polystyrene, polyvinyl chloride, polyurethanes, polyethylene, polyepoxides, phenol- and carbamideformaldehyde resins, and, of course, certain organosilicon polymers. 

Polycarbosilanes, in their broadest definition, are organosilicon polymers whose backbone is composed of silicon atoms, appropriately substituted, and difunctional organic groups which bridge the silicon atoms, as shown in formula 1. The polycarbosilanes may be linear, or they can be cyclic or polycyclic -... 

Organosilicon Polymers as Precursors for Silicon-Containing Ceramics... 

We have described new routes to useful preceramic organosilicon polymers and have demonstrated that their design is an exercise in functional group chemistry. Furthermore, we have shown that an organosilicon polymer which seemed quite unpromising as far as application is concerned could, through further chemistry, be incorporated into new polymers whose properties in terms of ceramic yield and elemental composition were quite acceptable for use as precursors for ceramic materials. It is obvious that the chemist can make a significant impact on this area of ceramics. However, it should be stressed that the useful applications of this chemistry can only be developed by close collaboration between the chemist and the ceramist. 

Photochemical Behavior of Organosilicon Polymers Bearing Phenyldisilanyl Units... 

Other organosilicon polymer precursors for ceramics have either been prepared or improved by means of transition metal complex-catalyzed chemistry. For instance, the Nicalon silicon carbide-based ceramic fibers are fabricated from a polycarbosilane that is produced by thermal rearrangement of poly(dimethylsilylene) [18]. The CH3(H)SiCH2 group is the major constituent of this polycarbosilane. 

Organosilicon polymers are especially important as imaging layers in bilayer resist processes(1). A wide range of organosilicon resist materials, in which the organosilicon compound has been incorporated either into the polymer main chain or into pendant groups, has appeared in the literature(2-8). However, almost all polymers have been... 

We have found that hydrophilic oiganic polymers treated with TiCLi have much higher etching selectivities than organosilicon polymers in an O2 plasma. This paper examines some of the parameters that influence the reaction of TiCLi with a variety of polymers. We find that TiCLi, readily functionalizes hydrophilic as well as moderately hydrophobic polymers, but fails to functionalize very hydrophobic films. Rutherford backscattering analysis reveals that TiCl4 is hydrolyzed at hydrophilic polymer surfaces that have sorbed water. Lack of surface water on hydrophobic polymers explains the absence of a TiC>2 layer on these polymer surfaces. 

Watanabe and Ohnishi [39] have proposed another model for the polymer consumption rate (in place of Eq. 2) and have also integrated their model to obtain the time dependence of the oxide thickness. Time dependent oxide thickness measurement in the transient regime is the clearest way to test the kinetic assumptions in these models however, neither model has been subjected to experimental verification in the transient regime. Equation 9 may be used to obtain time dependent oxide thickness estimates from the time dependence of the total thickness loss, but such results have not been published. Hartney et al. [42] have recently used variable angle XPS spectroscopy to determine the time dependence of the oxide thickness for two organosilicon polymers and several etching conditions. They did not present kinetic model fits to their results, nor did they compare their results to time dependent thickness estimates from the material balance (Eq. 9). More research on the transient regime is needed to determine the validity of Eq. 10 or the comparable result for the kinetic model presented by Watanabe and Ohnishi [39]. 

Tanaka, M. Hatanaka, Y. Hydrosilylation and Silylation in Organosilicon Polymer Synthesis. In Silicon-based Polymers The Science and Technology of their Synthesis and Application-, Jones, R. G., Ando, W., Chojnowski, J., Eds. Kluwer Dordrecht, 2000 pp 439460. 

Organosilicon polymers, 1020 Original sources of chemical informa tion, 1127... 

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