INFLUENCE OF SOLVENTS ON GAMMA-RAY POLYMERIZATION OF ACRYLIC-ACID .2.

In the reported experimental study, two groups of solvents have been characterized by examination of the monomer's association forms in solution. In a first group of solvents (methanol-dioxan-water), the aggregates are maintained and reinforced; in the second one, acrylic acid exists only as cyclic dimers (hydrocarbons-chlorinated solvents). The difference between the association forms of the monomer involves some important modifications on the kinetics of polymerization and the structure of the obtained polymers. In the solvents of the first group, the obtained polymers are crystallizable and may involve syndiotactic sequences, while in the presence of the solvents of the second group no crystallization or stereoregularity of the polymer can occur. A very close correlation is thus found between the aggregated structure of the monomer, the polymerization kinetics, and the structure of the polymers.