摘要
为了制备具有[SiN_(3)O]结构单元、陶瓷化温度低的聚硅氮氧烷(PSOZ)先驱体,以三异氰基甲基硅[MeSi(NCO)_(3))]为原料,采用部分水解和氨解反应,制备了PSOZ先驱体。通过控制MeSi(NCO)_(3)水解反应的pH(4.7、5.4、5.9)、物料比[n(H_(2)O)∶n(MeSi(NCO)_(3))=1∶3、1∶2、2∶3]和水解温度(-10、-20、-30、-40、-50℃),提高二硅氧烷中间体的产率,进而提高PSOZ先驱体的陶瓷产率,并研究了PSOZ的热解特性。结果表明:1)PSOZ在800℃时完成无机化,此时试样中的硅甲基(Si—CH_(3))和异氰基(—NCO)完全分解;经1400℃热处理后,产物开始陶瓷化转变,局部出现Si_(2)N_(2)O微晶;经1600℃热处理后,得到高结晶的Si_(2)N_(2)O陶瓷;2)在pH=4.7、n(H_(2)O)∶n(MeSi(NCO)_(3))=1∶2,水解温度为-40℃的条件下制备的PSOZ先驱体的陶瓷产率最高,为57.1%(w)。
To possess the[SiN_(3)O]structure and low ceramization temperatures,polysiloxazane(PSOZ)precursors were prepared using triisocyanomethylsilicon[MeSi(NCO)_(3)]as the raw material by partial hydrolysis and ammonolysis reactions.The yield of disiloxane intermediate was increased by controlling the pH(4.7,5.4 and 5.9),material mole ratio(n(H_(2)O)∶n(MeSi(NCO)_(3))=1∶3,1∶2 and 2∶3)and hydrolysis temperature(-10,-20,-30,-40 and-50℃)of MeSi(NCO)_(3)hydrolysis reaction,thus increasing the ceramic yield of PSOZ precursors.The pyrolysis characteristics of PSOZ precursors were further studied.The results show that:(1)PSOZ precursors complete the inorganicization at 800℃;the silicomethyl[Si—CH_(3)]and isocyano[—NCO]in the sample are completely decomposed;after heat treatment at 1400℃,ceramization begins,and Si_(2)N_(2)O microcrystals appear locally in the sample;after heat treatment at 1600℃,highly crystalline Si_(2)N_(2)O ceramics are obtained;(2)under the conditions of pH of 4.7,n(H 2O)∶n(MeSi(NCO)_(3))of 1∶2 and hydrolysis temperature of-40℃,the ceramic yield of the PSOZ precursor is the highest,57.1 mass%.
作者
徐汇
杜贻昂
王福稳
李威
徐娜娜
欧钰城
王兵
Xu Hui;Du Yiang;Wang Fuwen;Li Wei;Xu Nana;Ou Yucheng;Wang Bing(Science and Technology and Composites Laboratory,National University of Defense Technology,Changsha 410073,Hunan,China;不详)
出处
《耐火材料》
CAS
北大核心
2024年第5期424-430,共7页
Refractories
基金
湖南省优秀青年自然科学基金(2021JJ20048)。
关键词
聚硅氮氧烷
无机化
异氰基
陶瓷化
polysiloxazanes
inorganicization
isocyano
ceramization
