STUDIES ON THE MOLECULAR-WEIGHT DEPENDENCE OF TACTICITY OF ANIONICALLY PREPARED PMMAS BY ONLINE GPC/NMR

Several PMMA samples prepared in toluene with anionic initiators such as t-C4H9MgBr, n-C4H9MgCl, 1,1-diphenylhexyllithium, t-C4H9Li and t-C4H9Li(n-C4H9)3Al complex were analyzed by the on-line GPC/NMR method using a 500 MHz 1H NMR spectrometer as a real-time detector of GPC. The molecular method for a short time (≤60 min per sample) with a small amount of the sample (≈1 mg). The plots of intensities of the α-methyl proton resonances due to mm- and rr-triads against elution time showed the variation of tacticity with molecular weight of the PMMA. On the basis of the results, the natures of active species in the polymerizations were discussed. © 1990 Springer-Verlag.