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 inherently attractive for medicinal applications as their components are considered pharmaceutically safe. The laboratory-scale synthesis of poly(acrylic acid) bonded onto a PEO-PPO-PEO triblock (Pluronic) backbone via dispersion polymerization is reported. Initial optimization of the synthesis defines appropriate levels of initial loading of acrylic acid and Pluronic, with a mixture of 2,2'-azobis(2,4-dimethylpentanenitrile) and lauroyl peroxide as an initiator system. The synthesis results in a copolymer with low residual monomer content and a very high degree of bonding between Pluronic and PAA. Diluted aqueous solutions of Pluronic-g-PAA exhibit rapid thermogelation. Rheological parameters of the copolymers urge on their ophthalmic applications.