超临界二氧化碳对硅橡胶硫化动力学的影响

Effect of supercritical carbon dioxide on vulcanization kinetics of silicone rubber

采用差示扫描量热法考察了超临界二氧化碳(scCO_(2))的饱和时间、饱和温度(T_(s))、饱和压力(P_(s))和过氧化二异丙苯(DCP)用量对甲基乙烯基硅橡胶(MVQ)非等温硫化动力学的影响,并根据Kissinger法计算得到MVQ的硫化表观活化能(E_(a)),通过Málek法和Seatak-Berggren自催化模型确定了可用于描述MVQ硫化动力学行为的参数。结果表明,随着DCP用量增加,E_(a)增大。MVQ在scCO_(2)中饱和12 h后E_(a)减少至117.0 kJ/mol。当Ts为70℃,P_(s)为20 MPa时E_(a)分别降至110.6 kJ/mol和109.4 kJ/mol。scCO_(2)饱和前后MVQ的硫化反应级数均约为1,硫化过程均表现出自催化反应的特征。

Differential scanning calorimetry(DSC)was used to investigate the effects of saturation time,saturation temperature(T_(s))and saturation pressure(P_(s))of supercritical carbon dioxide(scCO_(2))and the amount of diisopropylbenzene peroxide(DCP)on the non-isothermal curing kinetics of methyl vinyl silicone rubber(MVQ).The apparent activation energy(E_(a))of MVQ vulcanization was calculated according to the Kissinger method,and the parameters that could be used to describe the kinetic behavior of MVQ vulcanization were determined by the Málek method and Seatak-Berggren autocatalytic model.The results showed that the Ea increased with the increasing amount of DCP.But E_(a) decreased to 117.0 kJ/mol after the MVQ was saturated in scCO_(2) for 12 h.When Ts was 70℃,and P_(s) was 20 MPa,E_(a) decreased to 110.6 kJ/mol and 109.4 kJ/mol,respectively.The order of MVQ vulcanization reaction before and after scCO_(2) saturation was about 1,and the vulcanization process showed the characteristics of autocatalytic reaction.