THE EFFECTS OF CROSS-LINKING AGENTS ON SOME PROPERTIES OF HEMA-BASED RESINS

The use of 2-hydroxyethyl methacrylate (HEMA)based polymer as a biocom patible material has been well-established. HEMA-based resins containi ng cross-linking agents have several potential clinical applications. It is hypothesized that the incorporation of cross-linking agent will improve the mechanical properties of HEMA-based polymers while reducin g water absorption and solubility. The purpose of the work reported he re was to test this hypothesis and to determine the most effective cro ss-linking agent. A relationship among flexural strength, modulus, wat er absorption and solubility, and concentration of crosslinking agent was demonstrated. Strength and modulus tend to increase as the cross-l inking agent concentration is increased, up to about 50%, after which the values level out or begin to fall. Water absorption drops with inc reasing cross-linking agent over the whole range of concentrations. So lubility tends to show a small decrease initially (up to 40%), followe d by a noticeable increase as cross-linking agent concentration is inc reased. The trends were similar for all cross-linking agents, although there were differences in the absolute values in all properties depen ding upon the type of cross-linking agent used.