title: Hydroxyapatite whiskers provide improved mechanical properties in reinforced polymer composites.
abstract: Synthetic hydroxyapatite (HA) whiskers have been utilized as a new, biocompatible reinforcement for orthopedic biomaterials. High-density polyethylene (HDPE) was reinforced with either the synthesized HA whiskers or a commercially available spherical HA powder using a novel powder processing technique that facilitated uniform dispersion of the reinforcements in the matrix prior to compression molding. Composites were processed for up to 60 vol % HA whiskers and up to 50 vol % spherical HA. The mechanical properties of the new composite biomaterials were examined by uniaxial tensile tests. As expected, increased volume fraction of either reinforcement type over 0-50 vol % resulted in increased elastic modulus, a maximum in ultimate tensile stress, and decreased work to failure. Composites reinforced with HA whiskers had higher elastic modulus, ultimate tensile strength, and work to failure relative to composites reinforced with spherical HA. Thus, HA whisker-reinforced HDPE composites possessed improved mechanical properties over those reinforced with spherical HA. HA whisker-reinforced composites were anisotropic due to alignment of the whiskers in the matrix during processing.
authors: Department of Aerospace and Mechanical Engineering, University of Notre Dame, 381 Fitzpatrick Hall, Notre Dame, IN 46556-5637, USA. rroeder@nd.edu
authors: Ryan K
authors: RK
authors: Roeder
authors: Michael M
authors: MM
authors: Sproul
authors: Charles H
authors: CH
authors: Turner
mesh_terms: D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000494:pharmacology / Q000592:standards*; D001696:Biomechanical Phenomena; D003188:Composite Resins / Q000138:chemical synthesis / Q000494:pharmacology*; D017886:Durapatite / Q000138:chemical synthesis / Q000494:pharmacology*; D008422:Materials Testing; D020959:Polyethylene / Q000494:pharmacology; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D003188:Composite Resins; D020959:Polyethylene; D017886:Durapatite