Relaxation Behavior of Poly(N-monosubstituted Methacrylamides)

Abstract

Abstract A free-oscillating torsional pendulum was used to investigate the effect of substituents R on the dynamic mechanical relaxation behavior of poly(N-monosubstituted methacrylamides) in the temperature interval from –196 to 130°C. A comparison with the corresponding polymethacrylates shows that the relaxation motion of the side groups R, which gives rise to the low temperature dispersion (below – 130°C), is virtually independent of whether R is attached to COO or CONH groups. On the other hand the obtained data give evidence that a strong intermolecular interaction and high steric hindrances suppress the onset of the motion of CONH–R side chains as a whole. For the same reason the glass transition temperature of the poly(N-monosubstituted methacrylamides) is about 100°C higher than that of the corresponding polymethacrylates. The incorporation of low molecular weight substances leads to reduction of the low-temperature dispersion and to formation of a new secondary dispersion at a temperature of abo...