Galukhin Andrey, Taimova Guzel, Nosov Roman, Liavitskaya Tatsiana, Vyazovkin Sergey
Alexander Butlerov Institute of Chemistry, Kazan Federal University, Kremlevskaya Str. 18, 420008 Kazan, Russia.
Department of Chemistry, University of Alabama at Birmingham, 901 S. 14th Street, Birmingham, AL 35294, USA.
Polymers (Basel). 2020 Oct 12;12(10):2329. doi: 10.3390/polym12102329.
This study investigates the kinetics of confined polymerization of bisphenol E cyanate ester in the nanopores of the three types of silica colloidal crystals that differ in the concentration and acidity of the surface-grafted proton-donor groups. In all three types of pores, the polymerization has released less heat and demonstrated a very similar significant acceleration as compared to the bulk process. Isoconversional kinetic analysis of the differential scanning calorimetry measurements has revealed that the confinement causes not only a dramatic change in the Arrhenius parameters, but also in the reaction model of the polymerization process. The obtained results have been explained by the active role of the silica surface that can adsorb the residual phenols and immobilize intermediate iminocarbonate products by reaction of the monomer molecules with the surface silanols. The observed acceleration has been quantified by introducing a new isoconversional-isothermal acceleration factor that affords comparing the process rates at respectively identical conversions and temperatures. In accord with this factor, the confined polymerization is 15-30 times faster than that in bulk.
本研究考察了双酚E氰酸酯在三种表面接枝质子供体基团浓度和酸度不同的二氧化硅胶体晶体纳米孔中的受限聚合动力学。在所有三种类型的孔中，与本体过程相比，聚合反应释放的热量更少，并且表现出非常相似的显著加速。差示扫描量热法测量的等转化率动力学分析表明，受限不仅导致阿累尼乌斯参数发生巨大变化，而且使聚合过程的反应模型也发生变化。所得结果通过二氧化硅表面的活性作用得到了解释，该表面可以吸附残留酚，并通过单体分子与表面硅醇的反应固定中间亚氨基碳酸酯产物。通过引入一个新的等转化率-等温加速因子对观察到的加速进行了量化，该因子能够比较在相同转化率和温度下的过程速率。根据该因子，受限聚合比本体聚合快15至30倍。
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