On the kinetics of polymer degradation in solution—XII. Radiolysis of poly(2,2,2-trichloroethyl methacrylate)

✍ Scribed by J. Rosiak; W. Schnabel

• Publisher: Elsevier Science
• Year: 1984
• Tongue: English
• Weight: 385 KB
• Volume: 20
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(84)90182-4

✦ Synopsis

The title compound (PTCMA) was irradiated in O2-free dioxane solution by 6°Co-7-rays or by 100nsec-pulses of 16 MeV electrons. At concentrations below ca 0.04 base mol/l, main-chain scission occurred as was concluded from the decrease of the light scattering intensity (LSI). G(S) -3.7 _+ 0.4 was independent of the polymer concentration and equal to G(S) observed with solid PTCMA. This result indicates that in dilute solution main-chain scission is induced by the direct action of radiation on the polymer. The free radical [presumably --C(CH3)--(CH2)--] giving rise to main-chain scission has a lifetime of 2.6 msec. It reacts with ethane thiol (k = 6.6 x 104M Isec 1). At concentrations above 0.04 base mol/l, the polymer crosslinked (gel formation, increase of the LSI according to 2nd order kinetics). It is assumed that crosslinking is due to the combination of radicals of the type --CH2--C(CH3)(COOCH2 .CC12)--formed via dissociative electron capture processes involving mainly electrons in spurs that otherwise recombine with parent ions. This conclusion was inferred from the finding that [(~,._~)1] K ~c (epolymer)2[(~'l,2)1: 1st half-life of LSI increase after the pulse, cp,,bm~: polymer concentration].