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Water diffusion in hydroxyethyl methacrylate (HEMA)‐based hydrogels formed by γ‐radiolysis
Author(s) -
Hill David J T,
Lim McKenzie C H,
Whittaker Andrew K
Publication year - 1999
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/(sici)1097-0126(199910)48:10<1046::aid-pi267>3.0.co;2-w
Subject(s) - methacrylate , self healing hydrogels , polymer , 2 hydroxyethyl methacrylate , polymer chemistry , (hydroxyethyl)methacrylate , diffusion , polymerization , materials science , fick's laws of diffusion , chemical engineering , copolymer , chemistry , composite material , thermodynamics , physics , engineering
Polymer hydrogels based upon methacrylates are used extensively in the pharmaceutical industry, particularly as controlled release drug delivery systems. These materials are generally prepared by chemically initiated polymerization, but this can lead to the presence of unwanted initiator fragments in the polymer matrix. In the present work, initiation of polymerization by γ‐irradiation of hydroxyethyl methacrylate, with and without added crosslinkers, has been investigated, and the diffusion coefficients for water in the resulting polymers have been measured through mass uptake by the polymers. The diffusion of water in poly(hydroxyethyl methacrylate) at 310 K was found to be Fickian, with a diffusion coefficient of 1.96 ± 0.1 × 10 11 m 2 s −1 and an equilibrium water content of 58%. NMR imaging analyses confirmed the adherance to a Fickian model of the diffusion of water into polymer cylinders. The incorporation of small amounts (0.2–0.5 wt%) of added ethyleneglycol‐dimethacrylate‐based crosslinkers was found to have only a small effect on the diffusion coefficient and the equilibrium water content for the copolymers. © 1999 Society of Chemical Industry