| 摘要 |
PURPOSE:To obtain the title compound of any desired MW and excellent storage stability, by subjecting a silazane precursor obtained by reacting anhydrous ammonia with a specified organohalosilane mixture to dehydrogenation, cyclization and crosslinking in the presence of a basic catalyst. CONSTITUTION:An organohalosilane mixture (a) of formula I or II [wherein R1-3 are each a 1-6C lower alkyl, a (substituted)vinyl, a (substituted)allyl, a 6-10C (substituted)lower aryl, tri- or di-(lower)alkylamino with the proviso that R1 may be H, and S is a halogen] is reacted with anhydrous ammonia (b) in a solution to obtain a cyclic or linear silazane precursor (A) of formula III or VI. Component A is subjected to dehydrogenation, cyclization and crosslinking in the presence of a basic catalyst (B) capable of eliminating the H atom from the N atom adjacent to the Si atom to obtain a polysilazane having a skeletal structure which comprises repeating units of formula V and in which the residues of units of formula IV in the precursor are connected together as structural units of formula VII.
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