Fatigue characterization of a hydroxyapatite-reinforced polyethylene composite. I. Uniaxial fatigue

Abstract

The fatigue behavior of 40 volume % hydroxyapatite-reinforced polyethylene composite (HAPEXtrade mark) at 37 degrees C in saline was determined. S-N curves for this material, both in fully reversed axial tension-compression and fully reversed torsion, have been established. In tension, the cycles to failure ranged from 1000 cycles at 13 MPa to more than 1 million cycles at 4.4 MPa while in torsion they ranged from 100 cycles at 14.4 MPa to more than 1 million cycles at 4.8 MPa. Changes in strain range, tangent modulus, and cyclic energy dissipated during fatigue loading also were examined. Torsional fatigue was found to be considerably more damaging than axial fatigue. The fatigue damage accumulation process occurring in the composite was monitored by observing the reduction in modulus and the increase in energy dissipated.

Evaluation of dynamic creep properties of surgical mesh prostheses—Uniaxial fatigue

“…Nasri and Lallam43 compared the loss modulus and fatigue resistance of two industrial polyamide fibers and expressed that, for a given level of loading, the sample with a smaller loss modulus was more resistant to failure by fatigue, when compared with one with a higher value of loss modulus. It is also worthy noting that the variation in CED of the meshes varied inversely to the recorded values of secant moduli; in line with the observations reported by other researchers 44, 45. An increase in secant modulus and decrease in CED is indicative of increasing polymer chain orientation, which normally occurs during the initial stages of a fatigue experiment.…”

Calcium Orthophosphate-Containing Biocomposites and Hybrid Biomaterials for Biomedical Applications

“…The history of implantable CaPO 4 /polymer formulations started in 1981 (however, a more general topic “ceramic-plastic material as a bone substitute” is, at least, 18 years older [ 179 ]) from the pioneering study by Prof. William Bonfield and colleagues at Queen Mary College, University of London, performed on HA/PE blends [ 180 , 181 ]. That initial study introduced a bone-analogue concept, when proposed biocomposites comprised a polymer ductile matrix of PE and a ceramic stiff phase of HA, and was substantially extended and developed in further investigations by that research group [ 66 , 182 , 183 , 184 , 185 , 186 , 187 , 188 , 189 , 190 , 191 , 192 ]. More recent studies included investigations on the influence of surface topography of HA/PE composites on cell proliferation and attachment [ 193 , 194 , 195 , 196 ].…”

Alginate/Hydroxyapatite Biocomposite For Bone Ingrowth: A Trabecular Structure With High And Isotropic Connectivity

“…Cell encapsulation in calcium alginate beads represents a well established method for cell protection from the host immune system, − but the biological inertness of alginate has largely hampered its use in all those applications where cell adhesion is mandatory for survival and proliferation. Moreover, while calcium cross-linked gels make use of a simple chemistry and can be introduced into the body in a minimally invasive surgery, they are generally associated over longer time intervals with poor shape definition and volume instability in vivo. , One possible approach to overcome the biological and mechanical limits of alginate is the use of HAp as inorganic reinforcing and osteoconductive component of alginate HAp composite scaffolds. − Hydroxyapatite reinforced polymer biocomposites offer a robust system to engineer synthetic bone substitutes with tailored mechanical, biological, and surgical functions. − Numerous studies have consistently shown that HAp typically exhibits excellent biocompatibility, bioactivity, and if porous, osteoconduction in vivo. ,, Therefore, the basic design rationale for preparing HAp-reinforced polymer composites is to further reinforce a solid biocompatible polymer matrix with a bioactive inorganic filler, mimicking the role of HAp in bone. In recent years, various alginate-based constructs for the use in bone engineering have been proposed. ,− …”