Alkaline hydrolysis of P(VAc‐co‐MMA) particles for vascular embolization procedures

Abstract

AbstractPoly(vinyl acetate) (PVAc)‐based particles are used in medical and biomedical applications, including vascular embolization (VE) procedures. However, to render the technique safer and reproducible, the hydrolysis of the microbeads must be performed in some applications in order to control the hydrophilicity of the material. For this reason, in the present work the alkaline hydrolysis of poly(vinyl acetate‐co‐methyl methacrylate)—P(VAc‐co‐MMA)—microbeads is investigated. The hydrolytic conversions of PVAc and poly(methacrylic acid) (PMMA) chains were evaluated in terms of the concentrations of methanol and acetate ions present in the reaction media, since these chemicals are by‐products of alkaline hydrolyses of the ester groups of the polymers. It was observed that all investigated variables (temperature, time, and alkaline concentration) exert important effects on the final extents of hydrolysis, although the occurrence of nonlinear synergetic effects imposes the use of multivariable statistical analyses for proper characterization of variable effects. Besides, given the heterogeneous nature of the reaction system and the higher resistance to hydrolysis offered by PMMA segments, the overall hydrolytic conversions of the microbeads were low, as required in VE procedures. Finally, hydrolyses of P(VAc‐co‐MMA) chains can also lead to cleavage of polymer chains, as confirmed by reduction of average molar masses of the analyzed materials.