氟化沥青性质与分子结构的关系

Correlation between properties and microstructure of pitch fluorides

在氟气中引入惰性气体——氮气,与三种不同结构的沥青(中间相炭微球、中间相沥青和各向同性沥青)在旋转式反应釜中进行反应,制得三种氟化沥青。研究了所制样品的表面能、与水的接触角、耐酸碱稳定性和热失重性能。结果发现:三种氟化沥青的性质既有共性又有差异。比如,均具有极低的表面能,耐酸碱性稳定;但是氟化反应速度不同,受热行为不同,表现在最大失重速率各有特点。从原料沥青的分子结构、氟化沥青分子结构及分子之间的相互作用和排列的角度分析,认为氟化沥青的分子结构和分子量大小分布是导致其物理性质不同的主要原因,原料沥青的组成和结构则是造成氟化反应速率差异的根本。

Three different pitch fluorides were prepared by the reaction of pitch grains with a gas mixture con- taining fluorine and nitrogen in a rotating nickel reactor. The raw pitches are mesophase microbeads, mesophase pitch and isotropic pitch. The surface energy, contact angle with water, the stability in acid or alkali media and weight loss upon heating were investigated. Results showed that the fluorinated reaction rate of the raw pitches and the weight loss rate of the pitch fluorides were quite different, which may be caused by the difference in the molecular weight distributions and the compositions of the raw pitches. However, the surface energies of the pitch fluorides were all low and the resistance of the pitch fluorides to acid or alkali was similar.