FREE-RADICALS FORMED UPON PHOTOLYSIS AND RADIOLYSIS OF POLYMERS .3. RADICALS AND GASEOUS PRODUCTS IN ALTERNATING COPOLYMER OF ETHYLENE AND CARBON-MONOXIDE

Reactions of the formation of free radicals by photolysis and gamma-ra diolysis of alternating copolymer of ethylene and carbon monoxide and their postradiation thermal and chemical transformations with increasi ng temperature for samples irradiated at 77 K were studied. The major photolytic process is polymer chain scission giving alkyl and acyl rad icals with a quantum yield phi(R) of 2 x 10(-4) and 10(-3) at 77 and 3 00 K, respectively. The main products of photolysis of the copolymer a t 300 K are carbon monoxide, ethane, and ethylene. In the radiolysis o f the copolymer at 77 K, the same terminal alkyl radicals [GRAPHICS] a nd radical ions [GRAPHICS] are formed. The proportion of the latter sp ecies at a dose less than or equal to 50 kGy is about 50% of the total amount of paramagnetic centers, The copolymer resembles polyethylene in radiation resistance: the yields of paramagnetic centers in these p olymers at 77 K are almost identical, G(R) = 6.0 species/100 eV.