差示扫描量热法研究丙烯腈-衣康酸共聚物的热稳定化

Study on Thermal Stabilization of Poly(acrylonitrile-co-itaconic acid) by Differential Scanning Calorimetry

应用差示扫描量热法(DSC)研究了衣康酸(IA)、气氛、升温速率对丙烯腈-衣康酸共聚物[P(AN-IA)]热稳定化的影响.IA能够显著降低放热峰起始温度、放热量和放热速率.P(AN-IA)共聚物的放热峰起始温度受气氛影响不大,却随着IA含量的增加而明显降低,表明在热稳定化过程中它可能首先以离子机理发生氰基环化反应,再发生氧化反应.提高升温速率会导致放热峰向高温偏移和放热速率加快.采用Kissinger法计算了不同IA含量共聚物的热稳定化活化能,结果表明IA可以有效降低活化能.

The effect of itaconic acid （IA）, atmosphere and heating rate on the thermal stabilization of acrylonitrile copolymer with itaconic acid [P（AN-IA）] was studied by differential scanning calorimetry （DSC）, showing that IA could significantly reduce the initiation temperature of the exotherm, and decrease the quantity and the rate of heat evolved in the DSC exotherm. The initiation temperature of the exotherm of P（AN-IA） was little influenced by the atmosphere, however, distinctly decreased with the enhancement of IA content in the copolymer, which implied that the initiation of nitrile cyclization reaction preceded the onset of oxidation reaction through an ionic mechanism. Promoting heating rate resulted in a shift of the exotherm to a higher temperature, and a more rapid liberation of heat. The activation energy was calculated with the Kissinger method, and the results showed that IA could efficiently decrease the activation energy.