| abstract |
PURPOSE: A spinning dope containing a dissolved polycarbosilane with a specific molecular weight and Si-C bonds as a major skeleton is extruded into fibers, the fibers are made infusible and roasted in ammonia to effect complete nitridization without any deterioration of characteristics whereby the novel titled fiber of high performance is obtained. n CONSTITUTION: A reactor is charged with xylene and sodium, heated under a stream of nitrogen gas and dimethyl dichlorosilane is added dropwise to effect polymerization. Further, borodiphenylsiloxane is added and heated to effect reaction to give a polycarbosilane, an organosilicon high-molecular weight polymer having a molecular weight of 800W50,000 and Si-C skeleton. Then, the product is used to prepare a spinning dope and the dope is extruded into fibers. The fibers are made infusible under no tension, then roasted in an ammonia gas stream at 800W1,650°C to give the objective fibers which are composed of amorphous particles or a mixture of amorphous and crystalline particles of Si 2 N 2 O and α-Si 3 N 4 of less than 500Å particle sizes at 1.3W0.5 N/Si and 1.0W0.05 O/Si ratios. n COPYRIGHT: (C)1986,JPO&Japio |