Masters Theses

Date of Award

5-1996

Degree Type

Thesis

Degree Name

Master of Science

Major

Polymer Engineering

Major Professor

Roberto S. Benson

Committee Members

Marion G. Hansen, Peter K. Liaw

Abstract

This research was an investigation for finding a suitable materials to model the mechanical properties of human bone. Polymer/ceramic particulate filled composites were used to achieve these objectives. The resin used as a matrix was nylon 6 and the particulate fillers were calcium and phosphate salts, CaCl2 and hydroxyapatite (Ca5(PO4)3OH). An analysis of the thermal and morphological properties was performed and these findings were related to the results of the mechanical data. Blend compositions ranged from a weight percent of 0.5 to 10% salt in the polymer matrix. Most analysis was performed on blends created by a solution mixing method, which facilitated interaction of the two phases. The results from the mechanical data were fitted to theoretical predictions for particulate composites. The theories used included the Sato-Furukawa prediction for reduced modulus, (E/E1), the Kerner model for ultimate tensile stress, and the Nielsen prediction for breaking strain. All blend samples exhibited a reduction in modulus from that of the pure material. The hydroxyapatite blends agreed well with the Sato-Furukawa prediction for this reduced modulus as a result of cavitation. CaCl2 blends exhibited an increase in tensile strength, which was contrary to that of the hydroxyapatite samples. Thermal properties showed that the 5.0% and 6.0% CaCl2 blends exhibited little, or no crystallization behavior. Comparisons of the 10.0% hydroxyapatite to that of reported values for trabecular bone agree favorably in the areas of tensile strength, strain to break, and to a lesser degree, elastic modulus. From these findings and previous research the composition of a full bone analogue is proposed and discussed.

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