Punyodom Winita, Limwanich Wanich, Meepowpan Puttinan, Thapsukhon Boontharika
Polymer Research Laboratory, Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand.
Center of Excellence in Materials Science and Technology, Chiang Mai University, Chiang Mai, Thailand.
Des Monomers Polym. 2021 Apr 11;24(1):89-97. doi: 10.1080/15685551.2021.1908657.
The kinetics of ring-opening polymerization (ROP) of -caprolactone (-CL) initiated by 1.0, 1.5 and 2.0 mol% of stannous(II) octoate/-hexanol (Sn(Oct)/-HexOH) wase successfully studied by non-isothermal differential scanning calorimetry (DSC) at heating rates of 5, 10, 15 and 20 °C/min. The DSC polymerization kinetic parameters of -CL were calculated using differential (Friedman) and integral isoconversional methods (Kissinger-Akahira-Sunose, KAS). The average activation energy ( ) values obtained from Friedman and KAS methods were in the range of 64.9-70.5 kJ/mol and 64.9-80.4 kJ/mol, respectively. The values of frequency factor () were determined from model fitting method using Avrami-Erofeev reaction model. The average values of for the ROP of -CL initiated by 1.0, 1.5 and 2.0 mol% of Sn(Oct)/-HexOH (1:2) were 7.3x10, 2.8x10 and 1.2x10 min, respectively. From kinetics studied, the polymerization rate of -CL increased with increasing initiator concentration. The performance of Sn(Oct)/-HexOH in the synthesis of poly(-caprolactone) (PCL) was investigated by bulk polymerization at temperatures of 140, 160 and 180 °C. Sn(Oct)/-HexOH (1:2) could produce high number average molecular weight ( = 9.0 × 10 g/mol) and %yield (89%) of PCL in a short period of time at Sn(Oct) concentration of 0.1 mol% and temperature of 160°C. The mechanism of the ROP of -CL with Sn(Oct)/-HexOH was proposed through the coordination-insertion mechanism.
通过非等温差示扫描量热法（DSC），在5、10、15和20℃/min的升温速率下，成功研究了由1.0、1.5和2.0 mol%的辛酸亚锡/正己醇（Sn(Oct)/正己醇）引发的ε-己内酯（ε-CL）的开环聚合（ROP）动力学。使用微分（弗里德曼）和积分等转化率方法（基辛格-赤平-ose，KAS）计算了ε-CL的DSC聚合动力学参数。从弗里德曼方法和KAS方法获得的平均活化能（）值分别在64.9-70.5 kJ/mol和64.9-80.4 kJ/mol范围内。频率因子（）的值通过使用阿弗拉米-埃罗菲耶夫反应模型的模型拟合方法确定。由1.0、1.5和2.0 mol%的Sn(Oct)/正己醇（1:2）引发的ε-CL的ROP的平均 值分别为7.3×$10^{10}$、2.8×$10^{10}$和1.2×$10^{10}$ min$^{-1}$。从动力学研究来看，ε-CL的聚合速率随引发剂浓度的增加而增加。通过本体聚合，在140、160和180℃的温度下研究了Sn(Oct)/正己醇在聚（ε-己内酯）（PCL）合成中的性能。在0.1 mol%的Sn(Oct)浓度和160℃的温度下，Sn(Oct)/正己醇（1:2）可以在短时间内产生高分子数均分子量（ = 9.0×$10^{4}$ g/mol）和高收率（89%）的PCL。通过配位插入机理提出了ε-CL与Sn(Oct)/正己醇的ROP机理。
