Hydroxyapatite-polyethylene

Wang, M., Joseph, R., and Bonfield, W., Hydroxyapatite-polyethylene composites for bone substitution effects of ceramic particle size and morphology. Biomaterials, 19, 2357, 1998. 

In order to obtain a bioactive material with a lower elastic modulus and ductility, Bonfield prepared a hydroxyapatite-polyethylene composite [50]. Hydroxyapatite powders can be dispersed in a polyethylene matrix up to 45 vol% without losing any ductility of the polymer. The resultant composite shows a Young s modulus value of about 3 GPa, an ultimate tensile strength of 22-26 MPa, and a fracture toughness, Kjc, of 2.9 MPa m [51]. This composite is already used clinically as an artificial middle ear bone, etc. 

Wang M, Bonfield W (2001) Chemically coupled hydroxyapatite-polyethylene composites structure and properties. Biomaterials 22 1311-1320... 

Smolko E, Romero G (2007) Studies on crossUnked hydroxyapatite-polyethylene composite as a bone-analogue material. Rad Phys Chem 76 1414-1418... 

Deb, S., Wang, M., Tanner, K.E., Bonfield, W, 1996. Hydroxyapatite polyethylene composites effect of grafting and surface treatment of hydroxyapatite. Journal of Materials Science-Materials in Medicine 7, 191-193. 

Fig. 11.2 Structural model of the composite of hydroxyapatite particles and high density polyethylene.

Bonfield, W., Grynpas, M.D., Tully, A.E., Bowman, J. and Abram, J. (1981) Hydroxyapatite reinforced polyethylene - a mechanically compatible implant. Biomaterials, 2, 185-186. 

Separation for measurement The basis of measurement depends on the ability to separate the unbound or free" Ag from the Ab-Ag complex, which itself relies on differences in properties between the two components while maintaining (that is not disrupting) the Ab-Ag complex (Figure 10.6). There are a number of reagents used for separation including charcoal, hydroxyapatite, ammonium sulfate and polyethylene glycol, but the method that will be considered here relies on the use of dextran-coated activated charcoal (see Figure 10.7). With inherent... 

Figure 2.31 A WAXD pattern of a composite sample containing ultra-high molecular weight polyethylene (PE) fibrils and nanoparticles of hydroxyapatite (HA). The arrow indicates the drawing direction in the composite sample.

Figure 10.32 TG curves of hydroxyapatite (HA)-ultra-high molecular weight polyethylene (UHMWPE) composites with different content HA particles. The legends indicate the nominal volume fraction of HA in the UHMWPE matrix.

Orthopedic Joint replacements (hip, knee) Bone plate for fracture fixation Bone cement Bony defect repair Artificial tendon and ligament Titanium, Ti-Al-V alloy, stainless steel, polyethylene Stainless steel, cobalt-chromium alloy Poly(methyl methacrylate) Hydroxyapatite Teflon, Dacron ... 

Kuche Loghmani, S., Farrokhi-Rad, M., and Shahrabi, T. (2013) Effect of polyethylene glycol on the electrophoretic deposition of hydroxyapatite nanoparticles in isopropanol. Ceram. Int., 36 (6), 7043-7051. 

Typically, the oil phase contained 78% monomer/co-monomer, 8% divinyl benzene (cross-linking agent), and 14% non-ionic surfactant Span 80 (Sorbitan monooleate), while the aqueous phase contained 1% potassium persulfate as the initiator. In most cases studied here, monomer is styrene and when elasticity of the polymer is required, 2-ethylhexyl acrylate (2EHA) was used (styrene/2EHA ratio is 1 4). Whenever additives/fillers are placed in the aqueous phase their amounts are stated as weight percent while the phase volume of the aqueous phase remains constant. In some cases, the aqueous phase contains 0.5% hydroxyapatite and 15% phosphoric acid which is used to dissolve the hydroxyapatite, or alternatively, the aqueous phase may contain varying amounts of water-soluble polymer, such as polyethylene glycol or polyethylene oxide. If the styrene-based PHP is to be sulfonated to obtain ionic-hydrophilic foam, the pre-dispersion of sulfuric acid within the pores is useful, if not essential, and in that case, acids (typically 10%) can be used as the internal phaseP . ... 

An important development of orthopaedic implants has been the development of artificial composites, which when combined with biomolecules will induce osteogenesis. The properties of hydroxyapatite (HA) materials have been studied over the years with a view to increasing elasticity. Because biocompatibility has been a problem when HA has been combined with various polyethylenes and polysulphones, polyhydroxyalkanoates (PHAs) and its chemical composites, a polymer of hydroxybutyric acid (PHB), copolymers of hydroxybutyric acid and... 

W. Bonfield, M.D. Grynpas, A.E. Tully, Hydroxyapatite reinforced polyethylene—a mechanically compatible implant material for bone replacement. Biomaterials 2, 185-186 (1981)... 

M. Ahmad, M.U. Wahit, M.R.A. Kadir, K.Z.M. Dahlan, Mechanical, iheological, and bioactivity properties of ultra high-molecular-weight polyethylene bioactive composites containing polyethylene glycol and hydroxyapatite. Sci. World J. 13, 474851 (2012)... 

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