Quantitative determination of unsaturation in photocured halogenated acrylates and methacrylates by FT-IR and Raman-spectroscopy and by thermal analysis
M. Johnck et al., Quantitative determination of unsaturation in photocured halogenated acrylates and methacrylates by FT-IR and Raman-spectroscopy and by thermal analysis, POLYMER, 40(13), 1999, pp. 3631-3639
The photo-polymerization of tetrachloroethylacrylate (TeCEA), pentafluoroph
enylacrylate (PFPA) and pentafluorophenylmethacrylate (PFPMA) was examined
by quantitative FT-IR and FT-Raman spectroscopy and by thermal analysis. Th
e agreement between the FT-Raman results and thermal analysis was good for
all monomers. The FI-IR measurement yielded higher percentages of unsaturat
ion than the two other techniques in the slowly reacting PFPMA polymer, whi
ch can be attributed to oxygen quenching effects. Calculations of unsaturat
ion based on spectroscopic measurements were carried out using the relative
band ratio method. The influence of the choice of the internal reference b
and on the unsaturation calculation was examined. The photo-polymerization
of the acrylates reached conversions of 95%-99% after irradiation of only a
few minutes, samples which contained PFPMA reached conversions of about 85
% after 1.5 h of irradiation. Volatile compounds in the resulting polymers
were quantified and identified by thermogravimetic analysis (TGA) and therm
al desorption followed by gas chromatography with mass spectrometric detect
ion (TD-GC-MS), respectively. Glass transition temperatures of the resultin
g polymers as determined by differential scanning calorimetry (DSC) vary fr
om 70 degrees C to 125 degrees C. (C) 1999 Elsevier Science Ltd. All rights
reserved.