Gel‐state NMR investigation of crosslinked poly(methy1 methacrylate) incorporating 13C labeled ethylene glycol dimethacrylate

13C labeled ethylene glycol dimethacrylate (EGDMA) was used to form labeled crosslinked PMMA and model 13 C labeled pendant double bond copolymers. Solution NMR was possible on solvent-swollen samples containing less than 0.5% by weight EGDMA. Spectra confirm significant amounts of singly reacted EGDMA in fully polymerized networks. Peaks arising from the two most likely stereochemical triads (syndi- and heterotactic) were identified but no evidence of cyclic species was observed. Labeled EGDMA allowed observation of the crosslink site at concentrations as low as 0.02 wt-% EGDMA.