偶氮二异丁腈引发液态聚碳硅烷的交联研究

STUDIES ON CROSS-LINKING OF A LIQUID POLYCARBOSILANE INITIATED BY 2, 2′–AZOBISISOBUTYRONITRILE

在偶氮二异丁腈(2,2′–azobisisobutyronitrile,AIBN)引发下,研究液态超支化聚碳硅烷(hyperbranched polycarbosilane,HBPCS)的无氧热交联,考察交联温度、AIBN用量以及时间对交联反应及陶瓷产率的影响。结果表明:较高的温度可促进交联;AIBN用量越多越有利于交联,陶瓷产率先增加而后稳定,其最佳用量为1.0%～2.0%(质量分数,下同);随着交联时间延长,HBPCS的交联程度和陶瓷产率先增加而后保持不变。对于AIBN用量1.5%的体系,HBPCS经80℃交联6h后,其1000℃下的陶瓷产率高达75%以上。此外,对最终陶瓷相组成进行表征,发现AIBN的引入能够有效抑制β-SiC的结晶。

Cross-linking reaction of a hyperbranched liquid polycarbosilane （HBPCS） initiated by 2, 2＇-azobisisobutyronitrile （AIBN） was studied at an inert atmosphere. The influences of temperature, AIBN amount and time on the cross-linking reaction and ceramic yield of HBPCS were investigated. The cross-linking reaction can be improved at a higher temperature. The increase of the amount of AIBN added is beneficial to promote the cross-linking, while the ceramic yield increases first and then remains stable with the increase of AIBN addition. The optimal range of mass fractions （the same below） of AIBN added to HBPCS is 1.0%-2.0%. With the increase of cross-linking time, the degree of cross-linking and ceramic yield of HBPCS increases first and then remains constant. The ceramic yield of cross-linked HBPCS with 1.5% AIBN at 80℃ for 6h reaches above 75% up to 1 000℃. In addition, the phase composition of the HBPCS-derived ceramics was characterized. It was found that the introduction of AIBN significantly retards the crystallization of β-SIC.