Behavior of Primary Radicals During Thermal Degradation of Poly(Methyl Methacrylate).
Behavior of Primary Radicals During Thermal Degradation
of Poly(Methyl Methacrylate).
Kashiwagi, T.; Inabi, A.; Hamins, A.
Polymer Degradation and Stability, Vol. 26, 161-184,
polymethyl methacrylate; thermal degradation; radicals
The behavior of the primary radicals formed from the
random scission of anionically polymerized poly(methyl
methacrylate). PMMA, during thermal degradation is
investigated by a theoretical and experimental study.
The theoretically calculated relationship between the
degree of polymerization and the conversion agrees well
with the experimentally determined relationship if the
random scission produces one polymer radical and one
polymer molecule with an unsaturated bond at a chain
end. It is proposed that the primary radical rearranges
to form the polymer molecule with the unsaturated bond
at a chain end. Two different degradation paths for this
rearrangement are proposed via beta scisison at the C-C
bond of the pendant group instead of beta scisison, as
previously thought, at the backbond C-C bond. The
products from the proposed degradation paths are CO,
CO2, CH3OH, AND CH4. The products for anionically
polymerized PMMA samples with three different values of
initial molecular weight are measured by a mass
spectrometer. The quantities of CO and CO2 are observed
to decrease with an increase in initial molecular
weight. This confirms that the two proposed degradation
paths for the thermal degreadation of PMMA are quite