Ammonia curing behavior of poly[(alkylamino)borazine] fiber
2012
The ammonia curing behavior of a novel poly[(alkylamino)borazine] fiber and the effect of curing temperature, holding time and heating rate were studied. The results revealed that temperature had a great impact on gel content. With increasing of temperature and holding time, the gel content, weight loss and reduction of carbon content increased. While with elevation of heating rate, the above indexes decreased. Ammonia curing not only made PPAB infusible to obtain BN fiber, but also favored primary removal of carbon and improvement of ceramic yield. During curing, C–H groups in polymer fiber were largely consumed while C–N bonds varied little. For the cured fiber with gel content of 99.5wt.%, the carbon content reduced from 22.67 to 18.79wt.%. Moreover, the ceramic yield of cured fiber at 1000°C in Ar was significantly improved from 53.2 to 73.8wt.%.
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