Study on the properties of crosslinking of poly(ethylene oxide) and hydroxyapatite-poly(ethylene oxide) composite

Abstract

This study covers the crosslinking of poly(ethylene oxide) (PEO) and its composite with calcium hydroxyapatite (HA), their mechanical and swelling properties, and morphology. Sheets of the composites of PEO (two different grades with Mv: 5 × 106 and 2 × 105) and HA and neat PEO were prepared by compression molding. The prepared composite and PEO (0.1-mm-thick) sheets were crosslinked with exposure of UV-irradiation in the presence of a photoinitiator, acetophenone (AP). This simple method for crosslinking, induced by UV-irradiation in the presence of AP, yielded PEO with gel content up to 90%. Gel content, equilibrium swelling ratio, and mechanical and morphological properties of the low molecular weight polyethylene oxide (LMPEO)-HA crosslinked and uncrosslinked composites were evaluated. Although the inclusion of HA into LMPEO inhibits the extent of crosslinking, the LMPEO-HA composite with 20% HA by weight shows the highest gel content, with appreciable equilibrium swelling and mechanical strength. The growth of HA in simulated body fluid solutions on fractured surfaces of LMPEO and also LMPEO-HA was found to be very favorable within short times. The dimensional stability of these samples was found to be satisfactory after swelling and deposition experiments. The good compatibility between the filler hydroxyapatite and poly(ethylene oxide) makes this composite a useful tissue-adhesive material.