COMPOSITE BIOMATERIALS BASED ON CERAMIC POLYMERS .1. REINFORCED SYSTEMS BASED ON AL2O3 PMMA/PLLA/

Composite biomaterials with good mechanical response and a partially b iodegradable character were prepared by the free radical polymerizatio n of mixtures of alpha-Al2O3, low-molecular-weight but crystalline pol y(l-lactic acid) (PLLA), and methyl methacrylate (MMA). Cylindrical sp ecimens prepared with different composition were characterized by ther mogravimetry, calorimetry, H-1-NMR spectroscopy, and x-ray diffraction (XRD). The in vitro biodegradative process was studied in different m edia, following variations of the pH, gravimetric weight loss of the s pecimens, and crystalline domain change by XRD after immersion in pure water and buffered solutions at pH 4.0 and pH 8.0 for 90 days. Format ion of a relatively porous structure with good cohesion after the biod egradative treatment (confirmed by SEM) was observed. These systems ca n be considered for applications in orthopedic surgery as filling biom aterials and even as control drug-delivery systems. (C) 1996 John Wile y & Sons, Inc.