Premium
The role of air in the radiolytic degradation of polycarbonate
Author(s) -
Gupta Mool C.,
Pandey Rajbahadur R.
Publication year - 1989
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19890270115
Subject(s) - crystallinity , radiolysis , irradiation , isothermal process , photodegradation , branching (polymer chemistry) , chemistry , thermal stability , nitrogen , bond cleavage , photochemistry , polymer chemistry , materials science , organic chemistry , radical , crystallography , photocatalysis , physics , catalysis , nuclear physics , thermodynamics
Bisphenol A polycarbonate (PC) was irradiated with Co‐60 γ‐rays at room temperature in presence of air or nitrogen. Changes were followed by IR and NMR spectroscopy as well as GPC, X‐ray diffraction, melting temperature, DTA, and isothermal TG. The changes observed include chain scission, chain branching/cross‐links, decrease in thermal stability, crystallinity and scission of the product. However, there are some differences in samples irradiated in presence of air as opposed to those irradiated in nitrogen, but many changes are similar. Air accelerates the radiolytic degradation of PC. The radiochemical yield of chain scission, G(s), increased to 0.20 from 0.13; the chain branching/cross‐links are less numerous as compared to those after irradiation in nitrogen the thermal stability decreases along with the temperature of that rate of maximum mass loss, crystallinity and the melting temperature. The chemical products in both air and nitrogen irradiations are almost identical. The formation of these products could be explained by multiple pathways‐free radical formation and by ring as well as side chain attack. The studies suggest that Fries' rearrangement is not an important pathway during the radiolytic degradation as compared with photodegradation.