用XRD研究高等规聚丙烯腈环化反应的反应度  

XRD studies of the extent of reaction of polyacrylonitrile heat-treated in air

作　　者：许志献[1] 徐晶[1] 徐樑华[1] 代永强[1] 金日光[1] 

机构地区：[1]北京化工大学化工资源有效利用国家重点实验室

出　　处：《北京化工大学学报（自然科学版）》2008年第3期39-42,共4页Journal of Beijing University of Chemical Technology(Natural Science Edition)

摘　　要：制备了不同三单元等规含量的聚丙烯腈(PAN),在空气气氛下模拟了预氧化过程,考察了温度、时间等条件对PAN环化反应的影响。用X-射线衍射仪(XRD)测定了预氧化物的XRD谱图,对XRD图谱进行分峰计算,求得2θ=16.5°处峰的面积和腈基的反应度。结果表明,随着预氧化环化温度或时间的增加,PAN中CN基团反应度逐渐增加,如反应温度在250℃和300℃的条件下分别预氧化10 min,三单元等规度为0.64和0.25的PAN中CN的反应度分别从0.38增加到0.91和从0.21增加到0.71。在相同的预氧化温度或时间的条件下,高等规度PAN分子中CN的反应度总是比低等规PAN的高,最大差值达0.35,且这种差别随温度的增加逐渐减小。Samples of polyacrylonitrile （PAN） with different tacticity have been synthesized. Pre-oxidized samples were prepared by heat treatment at different temperatures from 250 to 300℃ in air for various times, and the effects of varying the temperature and heating time on the extent of cyclization of PAN were investigated by X-ray diffraction. Fitting of the XRD peak at 2θ = 16.5° was carried in order to calculate the peak area and hence the extent of cyclization of the cyano groups. The extent of reaction showed a gradual increase with increasing temperature and heating time e.g. the extent of reaction of the nitrile groups in a PAN sample with mass ratio tactility of 0.64 heated for 10 min increased from 0.38 to 0.91 when the temperature was raised from 250 to 300 ℃, whilst a sample of PAN with mass ratio tactility of 0.25 showed an increase in extent of reaction from 0.21 to 0.71 under the same conditions. For the same temperature and heating time, the observed extent of reaction of the nitrile groups was always larger for i-PAN than for a-PAN; the maximum observed difference in extent of reaction between i-PAN and a-PAN was 0.35.

关 键 词：聚丙烯腈 预氧化 反应度 等规度 

分 类 号：TQ050.425[化学工程]