Chen J, Hua F, Qiu J, Yang Y
Department of Macromolecular Science, Key Lab of Molecular Engineering for Polymeric Materials, Fudan University, 200433 Shanghai.
Guang Pu Xue Yu Guang Pu Fen Xi. 2001 Feb;21(1):47-53.
Three types of living radical polymerization processes were monitored by means of FTIR spectrometer with handful diamond detector called as Dicomp in situ. It was found that both styrene and styrene/hydroxylpropyl methyacrylate (HPMA) could polymerize according to stable free radical polymerization (SFRP) mechanism in presence of 4-hydroxyl tetramethypiperidiyl-1-oxy(HTEMPO). For styrene/HPMA system, the styrene and HPMA conversion monitored by FTIR were linear with increase of molecular weight, but it gave longer induction period compared with that for St bulk polymerization. It was related to the hydrogen-transfer reaction between the propagating radicals with the end HPMA unit and HTEMPO. Furthermore, This following method in situ could be introduced into monitoring heterogeneous polymerization of styrene during atom transfer radical polymerization (ATRP). The apparent kinetics was found to be about zero order and not 1.0 order, due to propagating on the complex including radicals, CuX and bpy in heterogeneous interface. The polymerization rate will be not related to the St in bulk St phase.
通过配备称为Dicomp的手持式金刚石探测器的傅里叶变换红外光谱仪原位监测了三种活性自由基聚合过程。研究发现，在4-羟基四甲基哌啶-1-氧基（HTEMPO）存在下，苯乙烯和苯乙烯/甲基丙烯酸羟丙酯（HPMA）均可按照稳定自由基聚合（SFRP）机理进行聚合。对于苯乙烯/HPMA体系，通过傅里叶变换红外光谱监测的苯乙烯和HPMA转化率随分子量增加呈线性关系，但与苯乙烯本体聚合相比，其诱导期更长。这与增长自由基与末端HPMA单元和HTEMPO之间的氢转移反应有关。此外，这种原位跟踪方法可用于监测原子转移自由基聚合（ATRP）过程中苯乙烯的非均相聚合。由于在非均相界面上在包括自由基、CuX和联吡啶的络合物上增长，发现表观动力学约为零级而非一级。聚合速率与本体苯乙烯相中的苯乙烯无关。
