EPR of C60 thermal/photochemical reactions with polystyrene and polymethyl methacrylate

Thermal and photochemical free radical reaction products of C₆₀ with polymethyl methacrylate (PMMA) and polystyrene (PS) in orthodichlorobenzene solution were detected by EPR (electron paramagnetic resonance). Thermal radicals (<100°C) of C₆₀/PMMA and C₆₀/PS samples gave single line first-derivative EPR spectra withg=2.0029. Ultraviolet photolysis of a C₆₀/PMMA solid phase sample gave two radical species; whereas, photolysis of a C_60/PS solid phase sample gave only one free radical. EPR signals were also recorded for UV and thermal C₆₀ reaction with free radical initiator, azobis(isobutyronitrile).