Effect of syndiotactivity on the aqueous poly (vinyl alcohol) gel

Influence of Syndiotacticity on Poly(vinyl alcohol)-Iodine Complex Formation

“…Go et al19reported that the PVA aqueous solutions gelled more easily with increasing syndiotacticity of PVA, based on the heats of fusion of the gels. Ogasawara et al 20 showed that even a 1% aqueous solution of S-PVA easily formed a gel with crystallite junctions. Matsuzawa et al21 discovered turbidity in S-PVA aqueous solutions at concentrations of 0É3È0É5 g l~1 at 40¡C.…”

Effect of syndiotacticity on the aqueous poly(vinyl alcohol) gel 2. Syneresis of gel

“…Therefore, the variation of those slopes of the C --T curves of the PVA gels with the rise of temperature is not due to the change of water but that of the structure of gel networks. In the previous paper (4) we found that junctions in aqueous PVA gel network consisted of crystallites formed by the syndiotactic parts.…”

“…and AH and that those exhibit so remarkable syneresis as not recognized in the gel of atactic PvA (4).…”

Rheological properties of syndiotacticity‐rich ultrahigh molecular weight poly(vinyl alcohol) dilute solution

“…6 -11 An aqueous solution of s-PVA formed hard elastic gel more easily than did that of a-PVA and the melting point of the s-PVA gel was remarkably higher than that of a-PVA gel. [12][13][14][15][16] a-PVA hydrogels for the drug delivery system have already been reported. [17][18][19][20][21][22][23] The gelation of PVA solution was suggested to occur with or without spinodal liquid-liquid phase separation according to the concentration and temperature of the solution.…”