Processing and properties of porous poly(L-lactide)/bioactive glass composites

Porous poly(L-lactide)/bioactive glass (PLLA/BG) composites were prepared by phase separation of polymer solutions containing bioactive glass particles (average particle size: 1.5 microm). The composite microstructures consist of a porous PLLA matrix with glass particles distributed homogeneously throughout. Large pores (>100 microm) are present in a network of smaller (<10 microm) interconnected pores. The porous microstructure of the composites was not significantly influenced by glass content (9 or 29 vol%), but silane pretreatment of the glass resulted in better glass incorporation in the matrix. Mechanical tests showed that an increase in glass content increased the elastic modulus of the composites, but decreased their tensile strength and break strain. Silane pretreatment enhanced the increase in modulus and prevented the decrease in tensile strength with increasing glass content. Composites soaked in simulated body fluid (SBF) at body temperature formed bone-like apatite inside and on their surfaces. The silane pretreatment of glass particles delayed the in vitro apatite formation. This bone-like apatite formation demonstrates the composites' potential for integration with bone.