含端炔基聚碳硅氮烷的合成、耐热及陶瓷化性能

Synthesis,Thermal Properties and Ceramization Performance of Ethynylaniline-Terminated Polysilazane

采用对苯二胺分别与甲基氢二氯硅烷(MeHSiCl2)或二甲基二氯硅烷(Me2SiCl2)胺解,以间氨基苯乙炔(APA)封端,制备含端炔基聚碳硅氮烷PCSN-A和PCSN-B。用FT-IR对其结构进行了表征,通过DSC研究了聚合物固化行为,采用TGA和XRD对其固化物的耐热性能和陶瓷化性能进行了研究。结果表明,PCSN-A由于结构内含有硅氢键(Si—H),Si—H键可参与固化,提高交联密度,其固化物具有优异于PCSN-B的耐热性能和陶瓷化性能,氮气下失重5%的温度(Td5)为564℃。氩气下1 450℃裂解的陶瓷化率为78.4%,得到β-SiC,α-SiC和α-Si3N4陶瓷,聚碳硅氮烷可用作耐高温树脂基体和陶瓷前驱体。

Two kinds of polysilazane ceramic precursors （PCSN-A/PCSN-B） were synthesized by the ammonolysis reaction of dichloromethylsilane （ MeSiHC12 ）/dimethyldichlorosilane （ Me2SiC12 ） and p-phenylenediamine terminated by m-amino-phenylacetylene （APA）. The structure of PCSN was characterized by FT-IR. Differential scanning calorimetry （DSC） was used to study the curing behavior. The thermal resistance and eeramization performance of the cured polymer were investigated by thermal gravity analysis （TGA） and XRD. The results showed that PCSN-A could be highly crosslinked at a low temperature through hydrosilylation reaction and Diels-Alder reaction due to the existence of Si--H bond. PCSN-A exhibited better thermal resistance and ceramization performance than PCSN-B. The temperature of 5% weight loss （Tds） Of PCSN-A was 564℃ in nitrogen. After sintering at 1 450℃ in argon, PCSN-A thermoset turned into black inorganic ceramics composited of β-SiC, α-SiC and α-Si3N4 with a yield of 78.4%, indicating its potential to be used as high temperature resistant resin matrix and ceramic precursor.