Quantification of End Groups in Anionically Polymerized Poly(methyl methacrylate)s by Pyrolysis−Gas Chromatography

End groups in anionically polymerized standard poly(methyl methacrylate)s (PMMAs) in the range of number average molecular weight ( M n ) = 2.0 × 10 4 to 1.3 × 10 6 with narrow molecular weight distribution were determined by pyrolysis−gas chromatography (Py-GC). The characteristic fragments reflecting the end groups on the pyrogram of the PMMAs were identified by comparison with those of a radically polymerized PMMA together with the mass spectra of the characteristic peaks on the resulting pyrograms taken by a gas chromatograph−mass spectrometer (GC-MS) system. Concentrations of the end groups determined from their relative peak intensities were interpreted in terms of M n and then compared with their reference values from the manufactures and those estimated by 1 H-NMR. By this method, direct determination of the end groups was possible even for PMMA with M n ≑ 10 6 without using any standard polymer samples.