DETERMINATION OF END GROUP FUNCTIONALITY IN POLY(METHYL METHACRYLATE)MACROMONOMERS BY PYROLYSIS SIMULTANEOUS MULTIDETECTION GAS-CHROMATOGRAPHY

The end groups in poly(methyl methacrylate) (PMMA) macromonomers and t heir radically polymerized prepolymers were determined using a pyrolys is gas chromatograph (Py-GC) equipped with a simultaneous multidetecti on system. End groups associated with the initiator azobis (isobutyron itrile) (AIBN) and the chain transfer reagents such as thioglycolic ac id and mercaptopropionic acid were of particular interest. Various cha racteristic pyrolyzates that reflected the end groups in the PMMAs wer e observed on the pyrograms. Pyrolysates that contain sulfur from the chain transfer reagent residues in the end groups were determined on t he basis of the pyrograms simultaneously obtained by a sulfur-selectiv e flame photometric detector and an ordinary flame ionization detester (Fl[D). On the other hand, the cyano-group-containing end groups cons isting of the AIBN residue were determined from the pyrograms simultan eously observed by FID and a nitrogen-phosphorus detector. The degree of polymerization estimated from the relative intensities of the end-g roup-specific pyrolyzates were comparable with those determined by siz e exclusion chromatography (SEC). Furthermore, the terminal ratio esti mated by Py-GC proved to be in good agreement with those calculated fr om kinetic data.