Influence of glass composition on the properties of glass polyalkenoate cements. Part IV: influence of fluorine content

Abstract

The influence of fluorine content of the glass in a series of glasses based on: 4.5SiO 2–3.0Al 2O 3–1.5P 2O 5–(5.0- X)CaO– XCaF 2 was investigated on their cement formation with poly(acrylic acid). Increasing the fluorine content of the glass was found to reduce the glass transition temperature, as a result of fluorine replacing bridging oxygens by non-bridging fluorines. Working and setting times of the cement pastes reduced with increasing fluorine content of the glass. Compressive strength and Young's moduli increased with fluorine content initially and then remained approximately constant. Fracture toughness, toughness and un-notched fracture strength were not significantly influenced by fluorine content. The results are consistent with fluorine simultaneously disrupting the glass network and reducing the basicity of the glass.