Thermodynamical aspects of the polymerization reaction of PMMA cement mixed with phosphatic mineral phases.

The main problem related to the use of polymeric cement in orthopaedics is the high temperature reached during the polymerization, causing necrosis. This paper reports a thermodynamical study of the polymerization reaction of an acrylic cement mixed with powdered phosphatic phases. In particular, mixing of alpha-tricalciumphosphate, beta-tricalciumphosphate and hydroxyapatite was proposed. Important preliminary results indicated that amounts of about 66% by weight of alpha-tricalciumphosphate reduced the polymerization temperature to about 58 degrees C in respect to 100 degrees C of pure acrylic cement. In addition, a special chamber was designed and realized to monitor the temperature variations involved during the polymerization reaction of the different mixtures.