聚醚砜酮炭膜炭化过程中炭结构形成

Formation of carbon structure during carbonization of poly (phthalazinone ether sulfone ketone) film

由XPS谱图分析出PPESK除了H以外的主要组成元素为C、N、O和S,且随着炭化温度的升高,N、O和S元素的质量分数减少,而C的质量分数增加;d002值由室温的0.45810nm降至950℃的0.35037nm,接近于石墨的标准层间距(0.33540nm),表明PPESK易于石墨化.根据FTIR谱带的变化规律,提出了样品在炭化时会沿着二氮杂萘环的N—N键断裂,形成共轭腈基及异氰基的苯环化合物.异氰基化合物进一步二聚成二苯基碳化二亚胺,后者又聚合生成含氮杂环的多环芳烃.继续炭化会导致芳杂环的合并和HCN等气态小分子的脱除,生成连续巨大的含氮杂芳环多环化合物.

The spectrum of XPS indicates that the main elements of PPESK except for H are C, O, N, S. Relative contents of O, N and S decrease, whereas C′s increases with the increase of pyrolysis temperature. By XRD, the value of d_(002) 0.458 10 nm (at room temperature) decreases to 0.350 37 nm (at 950 ℃), approaching to the standard value (0.335 40 nm) of graphite, which indicates PPESK easily graphitizes. From the variations of the spectral bands of FTIR, it is suggested that the scission of the phthalazine ring along N-N bond has emerged during carbonization, the compounds of the phenyl with the conjugated nitrile group and the isocyan group are formed. As the isocyan group polymerization progresses, the diphenyl carbondiimine may be formed; whereas the latter continuously polymerizes, and the polycyclic aromatic compound containing nitrogen heterocycle may be formed. Further continuous carbonization should lead not only to a combining of the heteroaromatic rings, but also to the evolution of the small molecule of hydrogen cyanide and the formation of the large polycyclic compound of the nitrogen-containing of the polyaromatic ring plane structure.