The gelation mechanism of solutions of isotactic polystyrene in cis-decalin

Tacticity and Counterion Modulated Temperature Response of Weak Polyelectrolytes: The Case of Poly(methacrylic acid) Stereoisomers in Aqueous Solutions

“…Van den Bosch et al have shown that a concentrated iPMA solution with α N = 0.28 forms an elastic gel while cooled below ∼0 °C. Similar behavior was reported previously for several neutral homopolymers in organic solvents − and was attributed to a two-step gelation mechanism, proposed also for iPMA. , …”

Competition between gelation and crystallization in solutions of syndiotactic polystyrene in cis-decalin

“…This was already observed in other systems where crystallization and gelation compete with each other. [22,23] But in this case the competition takes place between two different crystallization processes. At T > 100 8C, the induction time for crystallization increases again.…”

“…The rate of the coil-helix transition that is at the origin of this structure formation is strongly temperature dependent and decreases very rapidly with increasing temperature. [19,[21][22][23][24] At T > 45 8C this rate decreases and less helix conformation is observed by FTIR. From 45 8C on, structure formation will proceed mainly through the formation of the meso-amodification.…”

Structure Formation in Isotactic Poly(methacrylic acid)

“…On heating, this absorption band disappears at much higher temperature, showing the typical hysteresis effect as observed also in the solutions of synthetic polymers in organic solvents. [1][2][3][4][5] Dynamic rheological observations during such a cooling-heating temperature scan inform about gelation by physical network formation. This transformation sets in around 0 °C.…”

“…Such a process was already proposed for other gelling systems. [1][2][3][4][5] c. Mechanical Properties of the Gels. The elastic properties of the formed gels are illustrated by the following experiments.…”