RELATIONSHIP BETWEEN THE MORPHOLOGY OF PMMA PARTICLES AND PROPERTIES OF ACRYLIC BONE CEMENTS

Bone cements are mainly based on acrylic polymers, poly(methyl methacr ylate) (PMMA) being the most representative. The curing process (cold curing) is the result of the free radical polymerization of a mixture of beads of PMMA and methyl methacrylate (MMA), initiated by benzoyl p eroxide (BPO) and activated by the presence of a tertiary amine, the m ost classical being N,N-dimethyl-4-toluidine (DMT). In this work the r esults on the effect of the size and size distribution of PMMA beads a nd the concentration of DMT and BPO on the setting parameters, the res idual monomer content and the mechanical properties (tension and compr ession) of the cured systems are presented. The use of relatively larg er diameter PMMA beads improves the characteristic parameters of the c uring process (decreasing the peak temperature and increasing the sett ing time), without detrimental effects on the mechanical properties of the cured cement.