Pyrolysis—gas chromatography of networks

Cis-1,4-polybutadiene was exposed to different doses of β-radiation (5–100 Mrad), and polybutadiene samples with different contents of 1,2- and 1,4-isomers were exposed to equal doses of radiation (50 Mrad). The cross-linked products were characterized by sol—gel analysis, distribution of the molar masses of the sol fraction, determination of the degree of swelling and compressibility, and pyrolysed by means of a Curie-point pyrolyser at 770°C in 4 s. Evaluation of the pyrograms taken with the help of a capillary gas chromatograph proved that pyrolysis—gas chromatography enables statements regarding the micro-structure of these cross-linked polymers to be made through the degradation products 1-cis-2- and 1-trans-2-dimethylcyclopropane, 2-methyl-1,3-butadiene and trans-1,3-pentadiene in a very short time without much preparation of the samples. The peak areas of 1,3-butadiene and 4-vinylcyclohexane can be used to characterize the network density.