Preparation of 3DP Hydroxyapatite/Polycaprolactone Composite by a Novel Sequential Infiltration Technique

Abstract

In this study, a novel sequential infiltration technique using both high and low molecular mass polymers was developed as a means to improve the toughness and mechanical integrity of three dimensional printed hydroxyapatite compared to typical polymer infiltration technique which employed only single molecular mass polymer. Biodegradable polycaprolactone (PCL, Mw ~ 10,000 designated low or Mw ~ 80,000 designated high) were selected as an infiltrant since it has shown good biocompatibility together with a high elongation and energy to failure as compared to other medical polymers. Characterizations including thermogravimetry analysis, flexural properties, in vitro degradation and liquid absorption were carried out. It was observed that the combination of high and low MW infiltration in sequence yielded greater increase in the flexural modulus, strength, elongation and energy at break than those of using only single molecular mass infiltration. This enhancement in mechanical properties was found to be due to the increase in the content of infiltrated polymer into the samples in combination with the synergic effect of low and high molecular mass polycaprolactone resulting from the sequential infiltration.