title: Diffusion coefficients of water and leachables in methacrylate-based crosslinked polymers using absorption experiments.
abstract: The diffusion of water into dentin adhesive polymers and leaching of unpolymerized monomer from the adhesive are linked to their mechanical softening and hydrolytic degradation. Therefore, diffusion coefficient data are critical for the mechanical design of these polymeric adhesives. In this study, diffusion coefficients of water and leachables were obtained for sixteen methacrylate-based crosslinked polymers using absorption experiments. The experimental mass change data was interpreted using numerical solution of the two-dimensional diffusion equations. The calculated diffusion coefficients varied from 1.05 × 10(-8) cm(2)/sec (co-monomer TMTMA) to 3.15 × 10(-8) cm(2)/sec (co-monomer T4EGDMA). Correlation of the diffusion coefficients with crosslink density and hydrophilicity showed an inverse trend (R(2) = 0.41). The correlation of diffusion coefficient with crosslink density and hydrophilicity are closer for molecules differing by simple repeat units (R(2) = 0.95). These differences in the trends reveal mechanisms of interaction of the diffusing water with the polymer structure.
authors.affiliation: Bioengineering Research Center, University of Kansas, Lawrence, KS, USA.
authors.forename: Ranganathan
authors.initials: R
authors.lastname: Parthasarathy
authors.forename: Anil
authors.initials: A
authors.lastname: Misra
authors.forename: Jonggu
authors.initials: J
authors.lastname: Park
authors.forename: Qiang
authors.initials: Q
authors.lastname: Ye
authors.forename: Paulette
authors.initials: P
authors.lastname: Spencer
mesh_terms: D000042:Absorption; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004058:Diffusion; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry* / Q000493:pharmacokinetics; D008954:Models, Biological; D008962:Models, Theoretical; D009994:Osmolar Concentration; D058105:Polymerization; D011108:Polymers / Q000737:chemistry / Q000493:pharmacokinetics*; D019279:Resin Cements / Q000138:chemical synthesis / Q000737:chemistry; D012995:Solubility; D014867:Water / Q000737:chemistry / Q000378:metabolism*
chemical_list: D003432:Cross-Linking Reagents; D008689:Methacrylates; D011108:Polymers; D019279:Resin Cements; D014867:Water; C095998:Adhesive cement