Polysilane polymers crosslinking

This route has been used to prepare, e.g., (PhMeSi) . Crosslinked polysilane polymers useful as precursors for silicon carbide are obtained by redistribution from chlorodisilanes ... 

Soluble crosslinked polysilane polymers have been made by reduction of n-hexyltrichlor-osilane with liq Na-K alloy promoted by ultrasound [cf Eq. (f)] °. 

Table 2. Quantum yields for oolymer scission and crosslinking for some representative polysilanes (SiR R )n (a) Molecular weights were measured by GPC using polystyrene calibration standards (b) Ban, H Sukegawa, K. J. Polym. Sci., Polym. Chem. Ed., 1988, 26, 521...

The quantum yields for scissioning ( >g) and crosslinking ( ) were determined for some representative polysilane derivatives both in solution and in the solid state (8). In all cases polymer scission is the predominant process and the values ranged from 0.2 to 1.0. For two cases, poly (methyl phenylsilane) and poly(cyclohexyl methylsilane) which were also examined in the solid state, the quantum yields were reduced by at least an order of magnitude from the solution values. 

The polymers evaluated are shown in Fig. 1. These twelve polymers cover typical types of organosilicon polymers, such as polysiloxane, ladder type polysiloxane, polysilane, polymethacrylate, polysilyl-styrene, and novolak. Polymers and were supplied by Shin-etsu Chemical Co., Ltd. Actually, polymer" 2 evaluated contains very small amount of vinylsiloxane for crosslinking by deep UV irradiation after coating, because the pure polysiloxane is a fluid at room temperature and is impossible to measure the etching depth. These polymers have Si-0 bonds in the main chain structure. Polymer was purchased from Shin Nisso Kako Co., Ltd. and was purified in house. Polymers 4 to 12 were synthesized in house. Polymers 1J and 12 have Si-0 bonds in side chain structure. Thermal Si02 1J was evaluated as a reference. ... 

Design and synthesis of hybrid polymers and of dendrimers for special applications and as building blocks for carbosilanes, polysilanes catalysis and highly crosslinked coatings. 

Polysilane copolymers also become conducting when they are doped with oxidizing agents. Treatment of copolymer 3 with arsenic pentafluoride affords a conducting polymer as shown in Table 15.2 [5,7]. Interestingly, when the crosslinked copolymer prepared from irradiation of a linear polysilane 3 with x = 0.5 and y = 1.0 is doped with arsenic pentafluoride, the conductivity of the polymer increases slowly, but eventually reaches a level of 2 x 10 S cm [5]. 

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