Radical polymerization of methyl methacrylate with ethane-1,1,2-triyltribenzene as an initiator and ethane-1,1,2-triyltribenzene-end polymers as macroinitiators

An unsymmetrical triphenylethane, ethane-1,1,2-triyltribenzene (ETB), was successfully prepared from phenyl lithium, trans-1,2-diphenylethylene, and methanol. Characterization of the compound was performed by ¹H and ¹³C nuclear magnetic resonance spectroscopy (NMR). The polymerization of methyl methacrylate (MMA) was performed in the presence of ETB at 85 °C or higher. The free radicals obtained were characterized by ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS). Gel permeation chromatography (GPC) traces of the average molecular weight of poly(MMA) (PMMA) showed a series of translations with increasing time. The average molecular weight of PMMA indicated narrow polydispersity, and a linear relationship was found between ln([M]₀/[M]) and polymerization time. These results indicated the “living” nature of the polymerization of MMA in the presence of ETB. The structure of ETB was also introduced to the end of polystyrene (PS), polyisoprene (PI), and polyisoprene-b-polystyrene (PIS) chains which were obtained by living anionic polymerization. Hence, they initiated radical polymerization of MMA as ETB-end-macroinitiators to obtain block copolymers. Thus, living anionic polymerization and this radical polymerization method were combined together to prepare block copolymers without the intermediate transformation step.