1984 Volume 41 Issue 12 Pages 745-753
The formation of hydrogen (H) bonds in the poly (methacrylic acid) -poly (vinyl methyl ether) (PMAA-PVME) polymer complex and its thermal behavior were studied by IR spectroscopy and dynamic mechanical measurements. The two PMAA with different tacticities (at-PMAA: S, 53.3; H, 42.4; I, 4.3 and st-PMAA: S, 76.3; H, 20.2; I, 3.5) were used. The molar ratios of PMAA/PVME in the polymer complexes precipitated from aqueous solutions were 50/50 for at-PMAA and 40/60 for st-PMAA. In the case of st-PMAA, the polymer complexes were obtained as precipitates in the fiber forms. At the same composition ratios as described above, the temperatures of primary dispersion of the films of the both PMAA series which were cast from methanol agreed with the dissociation temperatures Td of the H bonds, respectively. This fact suggests the glass transition is mainly governed by the breakdown of H bonds. The films in the st-PMAA series showed higher H bonding abilities and Td, which was attributable to the structural regularity of the polymer complexes. The energy differences of the H bonds between carboxyl and ether oxygen and between carboxyl and carboxyl (dimeric form) were 13.8 kJ mol-1 in the 50/50 film for at-PMAA series and 20.9 kJ mol-1 in the 40/60 film for st-PMAA series.
