The growth of sparingly soluble salts on polymeric substrates

Abstract

Polymers such as the commercially available Porapak-N and synthetically prepared polystyrene (1.5% w/w) divinyl benzene copolymer and polystyrene have been converted into substrates appropriate for the deposition of hydroxyapatite (Ca 5(PO 4) 3OH, HAP) by the introduction of various phosphate groups on their surface. The investigation was carried out at sustained supersaturation at 37°C for the styrene (1.5% w/w) divinyl benzene copolymer and at 25°C for Porapak-N and polystyrene. In the former case the apparent crystal growth order was found to be 1.25 as for the growth on HAP seed crystals. Increasing the content of phosphate in the surface resulted in higher rates of mineralization. At 25°C higher apparent orders of reaction were observed possibly due to the microporous structure of the polymers employed.