Radiation effects on poly(1-chloro-1-alkynes)

The γ-radiolysis behavior of poly(l-chloro-1-alkynes) [ [rlap{--} ({rm CCI} = {rm CR}rlap{--} )_n ;{rm R} = n - {rm alkyl}] ] greatly changed with the length of alkyl group and with the presence or absence of oxygen. When γ-irradiated in air, poly(l-chloro-1-hexyne) (R = n-C₄H₉) decomposed to oligomers; its G_s value was as large as 5.4. When irradiated in vacuum, this polymer partly gelled. In contrast, poly(l-chloro-1-decyne) (R = n-C₈H₁₇) partly gelled even by irradiation in air. A high-dose irradiation of this polymer in vacuum resulted in the quantitative formation of a gel. The polymers irradiated in air contained carbonyl and hydroxyl groups, indicating the participation of oxidation reaction. Comparison with their thermolysis leads to a conclusion that these Cl-containing polyacetylenes are radiation-sensitive irrespective of their high thermal stability.