Synthesis and Characterization of Poly (methyl Methacrylate-styrene) Copolymeric Beads for Bone Cements

Acrylic bone cements have been used for about 40 years to fix artificial prosthesis to bone structure. The properties of the acrylic bone cement mostly depend on the characteristics of the beads, which are the main component of the solid part of the cement. In this work beads of poly(methyl methacrylate-co-styrene) were synthesized by suspension polymerization. The objective of this study was to obtain polymeric beads with particle size distributions and molecular weights that will permit the formulation of bone cements according to the international standards. Polyvinylpyrrolidone and polyvinylpyrrolidone-hydroxyapatite mixtures were studied as stabilizers of the system. Benzoyl peroxide (0.1, 1.0, 1.5% wt. in reference to the monomer) was the initiator of the reaction. The copolymeric beads were characterized by different analytical techniques. Polyvinylpyrrolidone alone was the best stabilizer and the bone cements prepared with polymer having low (247,000 g/mol) and high (800,000 g/mol) weight average molecular weights had static mechanical properties according to the requirements of commercial materials.