POLYETHER-MODIFIED POLY(ACRYLIC ACID) - SYNTHESIS AND APPLICATIONS

Poly(acrylic acid) (PAA) copolymers modified with block-copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) are inheren tly attractive for medicinal applications as their components are cons idered pharmaceutically safe. The laboratory-scale synthesis of poly(a crylic acid) bonded onto a PEO-PPO-PEO triblock (Pluronic) backbone vi a dispersion polymerization is reported. Initial optimization of the s ynthesis defines appropriate levels of initial loading of acrylic acid and Pluronic, with a mixture of 2,2'-azobis(2,4-dimethylpentanenitril e) and lauroyl peroxide as an initiator system. The synthesis results in a copolymer with low residual monomer content and a very high degre e of bonding between Pluronic and PAA. Diluted aqueous solutions of Pl uronic-g-PAA exhibit rapid thermogelation. Rheological parameters of t he copolymers urge on their ophthalmic applications.