Residual monomer content in bone cements based on poly(methyl methacrylate)

Acrylic bone cements are widely used in orthopaedics, and it is generally accepted that due to the vitrification phenomenon the monomer does not reach complete conversion after the cure of the resin. The degree of polymerization attainable in a commercial acrylic bone cement based on poly(methylmethacrylate) (PMMA) has been investigated by differential scanning calorimetry (DSC) using isothermal and dynamic modes. Because DSC tends to be less sensitive at high conversions, especially if there exists a permanent residue, gas chromatography (GC) was also used. The residual monomer has also been determined in samples cured under adiabatic conditions. The autocatalytic model developed by Kamal is used to analyse the curing kinetics. The final kinetic model is satisfactorily applied to dynamic and isothermal curing reactions.