Rheological properties of acrylic bone cement during curing and the role of the size of the powder particles

Abstract

A dynamic compressive rheometric technique was used to determine the true or complex viscosity (η*) of three poly (methyl methacrylate), PMMA-based bone cement formulations (one commercially available and two experimental), as a function of the time that elapsed from commencement of hand mixing of the cement constituents (t). For each cement, two rheological parameters [namely, the time of onset of cure (t ons) and the critical cure rate (CCR), which is herein defined as the complex viscosity rate computed at t ons] were determined from the η*-t data. For each cement, particle analysis was used to obtain the powder particle size distribution, from which the following parameters were obtained: (a) the overall mean particle diameter D m, and (b) the relative amounts of small-sized PMMA beads (mean diameter d between 0 and 40 μm) (α) and large-sized PMMA beads (d > 75 μm) (β). It is seen that the key particle parameter is not D m per se but α and β. Thus, the highest values of t ons and CCR were obtained from a cement with the highest values of α and β. An explanation for these trends is given, and two areas for further research work in this field are outlined. © 2002 John Wiley & Sons, Inc.

Publication Title

Journal of Biomedical Materials Research

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