The synthesis, by two different reaction pathways, of boron-modified polysilylcarbodi-imides of general type {B[C 2 H 4 Si(R)NCN] 3 } n (R = singly bonded organic ligand) and the plasticforming and the thermal behavior of these polymers are described. Compounds {B[C 2 H 4 Si(R)NCN] 3 } n [2a, R = H; 2b, R = CH 3 ; 2c, R = (NCN) 0.5 ] can be obtained by treatment of the vinyl-substituted polysilylcarbodi-imides [(H 2 C=CH)(R)SiNCN] n [1a, R = H; 1b, R = CH 3 ; 1c, R = (NCN) 0.5 ] with borane dimethylsulfide BH 3 ÁS(CH 3) 2. The polysilylcarbodi-imides 1a-1c themselves are accessible via the reaction of vinyl-substituted chlorosilanes (H 2 C=CH)-(R)SiCl 2 with cyanamide H 2 N-CN in the presence of pyridine or by a non-oxide sol-gel process of vinylated chlorosilanes and bis(trimethylsilyl)carbodi-imide, (H 3 C) 3 SiN=C=N-Si(CH 3) 3. In the second method for the synthesis of 2a-2c, hydroboration of vinylsubstituted chlorosilanes (H 2 C=CH)(R)SiCl 2 with borane dimethylsulfide, borane trimethylamide or borane triethylamide to yield the tris[(chlorosilyl)ethyl]boranes B[C 2 H 4 Si(R)Cl 2 ] 3 (3a, R = H; 3b, R = CH 3 ; 3c, R = Cl) is followed by treatment of the as-obtained compounds with bis(trimethylsilyl)carbodi-imide, which results in the formation of the hydroborated polysilylcarbodi-imides 2a-2c. The thermogravimetric behavior of the polymers 1a-1c and 2a-2c up to 2300°C is reported. It is shown that boron-modified polysilylcarbodi-imides are suitable precursors for the preparation of dense bulk ceramics. Therefore, the preparation of green bodies of the hydroborated polysilylcarbodiimides 2a-2c by plastic forming (PF) is described. A series of experiments points to the fact that the microstructure of the as-obtained ceramic monoliths obtained by subsequent thermolysis of the plastic-formed green bodies is strongly influenced by the conditions during plastic forming.
Boron-Modified Polysilylcarbodi-imides as Precursors forSi-B-C-N Ceramics: Synthesis, Plastic-Forming and High-Temperature Behavior. --(WEINMANN, M.; HAUG, R.; BILL, J.; DE GUIRE, M.; ALDINGER, F.; Appl.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.