Diffusion and solubility of commercial poly(methyl methacrylate) denture base material modified with dimethyl itaconate and di-n-butyl itaconate during water absorption/desorption cycles

Abstract

This study evaluated the water absorption, solubility, kinetics of water diffusion and residual monomer content of commercial poly(methyl methacrylate) (PMMA) denture base material modified with dimethyl itaconate (DMI) and di-n-butyl itaconate (DBI). Water absorption and solubility were measured gravimetrically while the residual monomer content was analysed using high-performance liquid chromatography with ultraviolet detection. It was found that the addition of di-n-alkyl itaconates significantly decreases the residual methyl methacrylate (MMA) content in the polymerized material. Maximum uptake (M8) and loss (M'8), and diffusion coefficients for absorption (Da) and desorption (Dd) of water through all materials were established. M8 shows a linear decrease with increasing amount of itaconate in the system while Da shows a linear increase with increasing amount of itaconate, both of these effects being more pronounced when DBI is present compared to DMI. M8 is a linear function of the value of Hoy's solubility parameter. The reduction in residual MMA promoted by addition of a small amount of di-n-alkyl itaconates can improve the applicative properties and biocompatibility of the PMMA denture base material. Also, it is shown that modification of the denture base material with di-n-alkyl itaconates can enable precise control of water absorption in the system.