TEGDA红外激光光聚合动力学的实时FTIR研究

Study on the Infrared Laser Induced Photopolymerization of TEGDA by Real Time FTIR

采用实时FTIR研究了二缩三乙二醇二丙烯酸酯的红外光聚合反应动力学。在红外激光照射下 ,引发剂 1,3 ,3 ,1’ ,3’ ,3’ -六甲基 - 11-氯 - 10 ,12 -亚丙基三碳菁—正丁基三苯基硼可以引发二缩三乙二醇二丙烯酸酯的光聚合反应。研究发现 ,随激光功率的提高 ,单体的聚合速度与双键转化率均有显著提高。在 17.0mW /cm2 光强下二缩三乙二醇二丙烯酸酯在 2 0s内双键转化率为 15 % ,聚合速度为 8.4× 10 -3 mol·L-1·s-1,并且初期反应速度与激光功率的 0 .47次方成正比 ,说明光聚合初期遵守双基终止的反应机理。由于分子链柔性的影响 。

In this paper, real time FTIR (RTFTIR) technique was employed to investigate the infrared laser-induced photopolymerization of triethylene glycol diacrylate (TEGDA). A novel cationic cyanine dye-borate complex, 1,3,3,1',3',3'-hexamethyl-11-chloro-10,12-propylene tricarbocyanine triphenylbutylborate, which has maximum electron absorption wavelength λ max at 786 nm, was used as the photoinitiator. The conversion of double bond (γ) and the polymerization rate (R p) have been determined from the drop of the absorption at 1 620 cm -1 and 1 635cm -1 in FTIR spectra under laser irradiation. It was found that γ increased rapidly and reached 15% with corresponding R p of 0.0084 mol·L -1 ·s -1 in the first 20 seconds when laser irradiation intensity was 17.0 mW/cm 2, higher laser irradiation intensity could lead to greater γ and R p. Furthermore, R p was proportional to the 0.47 power of the laser power at the first few seconds' irradiation. This demonstrated that the termination mechanism of photopolymerization was coupling between two propagating radicals at the beginning stage of photopolymerization. Compared with TEGDA, diethylene glycol diacrylate(DEGDA) had shorter soft chain and its final conversion was lower under the same irradiation conditions.