Syndiotactic poly(N-n-propylacrylamide) shows highly cooperative phase transition.
Syndiotactic poly(N-n-propylacrylamide)s (PNNPAM) with various racemo (r) diad contents were synthesized, and their phase transition behaviors were studied by high-sensitivity differential scanning calorimetry and FT-IR spectroscopy. The cooperativity of the phase transition increased with the increase in the r diad content. Compared with the atactic PNNPAM, the number of cooperative units, which shows the monomeric units length undergoing cooperative phase transition, increased 2.5- to 4-fold in the syndiotactic polymers. From the results of FT-IR spectroscopy and quantum chemical calculations, it was determined that the high cooperativity of the syndiotactic polymers resulted from local formation of an ordered structure in a dehydrated state.
Mori
Takeshi
T
Department of Applied Chemistry, Center for Future Chemistry, and Institute for Material Chemistry and Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan. moritcm@mbox.nc.kyushu-u.ac.jp
Hirano
Tomohiro
T
Maruyama
Atsushi
A
Katayama
Yoshiki
Y
Niidome
Takuro
T
Bando
Yoichi
Y
Ute
Koichi
K
Takaku
Shinji
S
Maeda
Yasushi
Y