DERIVATIZATION OF PREFORMED POLYMERS TO PRODUCE CERAMIC PRECURSORS

The feasibility of producing derivatized preformed polymers to be used as ceramic precursors was explored. A borane derivative of polyethyleneimine (PEI) was prepared through a transamination reaction involving Me3NBH3. Higher boron loadings were possible with Me3NB3H7. The borane derivative could be cast into films and produced boron nitride upon pyrolysis. Similarly, polyethyleneimine hydrochloride was converted into the cyanohydroborate derivative through a reaction with NaBH3CN. This derivative was also accessible through a transamination reaction. Both materials produced boron nitride upon pyrolysis. Polyallylamine hydrochloride could not be derivatized. Silyl derivatives of PEI were also prepared, but the products obtained afforded low ceramic yields upon pyrolysis. Copyright © 1990, Wiley Blackwell. All rights reserved