聚异丙胺基环硼氮烷裂解制备氮化硼及其抗氧化与介电性能

以异丙胺和三氯环硼氮烷(TCB)为原料,在较温和条件下合成了一种可溶可熔的聚异丙胺基环硼氮烷(PTPiAB),后经高温裂解制得六方氮化硼(h-BN).利用元素分析、TGA、FTIR、XRD和网络分析仪等对先驱体及裂解产物的组成、结构和性能进行了表征.结果表明,PTPiAB的结构中含有B3N3六元环,N-H、C-H和C-N键,其熔点约70 oC.1000 oC时在NH3和Ar中的陶瓷产率分别为45.9 %和52.8 %.NH3中裂解失重主要发生在800 oC以下,1000 oC左右开始结晶,1800 oC时得到BN的(002)晶面间距为0.334 nm,密度为2.03 g·cm-3.该BN表现出了较好的高温抗氧化性能,在空气中900 oC以下增重小于0.3%.此外,室温下测试频率为10 GHz时的介电常数实部和损耗角正切分别为2.48和0.03.

Oxidation Resistance and Dielectrical Properties of Boron Nitride by Pyrolysis of Poly (isopropylamino) borazine

Polytri(isopropylamino)borazine] (PTPiAB), a soluble and fusible precursor to hexagonal-BN (h-BN), was synthesized under mild conditions using isopropylamine and trichloroborazine (TCB) as starting materials. h-BN was obtained by pyrolysis of PTPiAB in NH3 and then in Ar. The composition, structure and properties of PTPiAB and pyrolytic product were investigated by using elemental analysis, FT-IR, XRD, TGA and Network Analyzer. The results indicate that N-H, C-H, C-N bonds and B3N3 units exist in the structure of PTPiAB. The melting point is 70 oC. The weight loss mainly occurs below 800 oC and ceramic yields for the precursor in NH3 and Ar are 45.9 % and 52.8 % at 1000 oC, separately. Crystallization occurs at around 1000 oC and the (002) interlayer spacing and density are 0.334 nm and 2.03 g·cm-3 at 1800 oC, respectively. Furthermore, the BN illustrates superior oxidation resistance with weight increase lower than 0.3% below 900 oC in air. The BN also displays low dielectric constants with real part of 2.45 and loss tangent of 0.03 at 10 GHz at ambient temperature, respectively.