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Flame Retardant and Smoke Suppressant Additives for Polypropylene: Vermiculite and Zinc Phosphate
Published in Ali Pourhashemi, Sankar Chandra Deka, A. K. Haghi, Research Methods and Applications in Chemical and Biological Engineering, 2019
Fatma Üstün, Hasan Demir, Devrim Balköse
The X-ray diffraction diagram of zinc phosphate seen in Figure 6.10 is very similar to that was reported for α-hopeite and β-hopeite (Zn3(PO4)2⋅4H2O).29 They both have orthorhombic crystals with a = 1.05 nm, b = 1.83 nm, and c = 0.50 nm, but the orientation of 1 mol of water are different in two forms.29,30 The most intense diffraction peaks observed in Figure 6.10 are at 2θ values of 9.67°, 19.41°, and 31.37° identical by that reported by Herske et al.30 for β hopeite. The peaks at 2θ values of 31.6°, 34.2°, and 36.10° indicated the presence of ZnO as impurity in the zinc phosphate according to JCPDS card number 79-0206.
New generation hopeite coating on Ti6Al4V (TC4) by radio frequency magnetron sputtering for prosthetic-orthopaedic implant applications: synthesis and characterisation
Published in Transactions of the IMF, 2020
Titanium alloys are widely used as bio-implants in orthopaedic and dental applications owing to their non-toxic character, high specific strength and superior biocompatibility.1 Titanium alloy, especially Ti6Al4V (TC4), systems have some serious issues of bio-inertness and release of aluminium and vanadium metal ions which affects the bone healing process.2–6 To overcome these issues researchers have tried to engineer the implant’s topography and surface composition.7 In view of the need for shortening the bone healing period and to increase the clinical success of Ti implants, various surface modification methods have been used.8 It has been reported previously in the literature that a bioceramic coating can prevent the release of toxic metal ions from the substrate into the environment.9 Similarly, a new generation multifunctional bioceramic coating of hopeite (hydrated zinc phosphate) can check the release of toxic ions from the surface of titanium alloys and ensure overall better bioactivity, largely because of the presence of phosphate which is the key element of osteoconductive ceramics, and zinc which is a well-known element for improving biomineralisation.10–12 Hopeite (Zn3(PO4)2·4H2O (hydrated zinc phosphate) is a candidate bio-implant material mainly used in dental implants, which can also promote bone growth.13–14 Hopeite formation offers low solubility, better adhesion, superior biocompatibility and excellent durability of dental cement.14–17 As reported in the previous literature, the hopeite layer effectively promotes HA re-growth in simulated body fluid (SBF) environment.13,18 Simulated body fluid (SBF) is a solution with an ion concentration close to that of human blood plasma. HA regrowth is attributed to the high concentration of calcium and phosphorus ions, which provides a favourable condition for HA nucleation.19 Previously conducted research has confirmed the HA-like layer formation on the surface of bioactive materials in the SBF environment, while the bulk remains unchanged.20–29 Hopeite coating is therefore expected to improve the overall biological activity of metallic implants, including titanium alloys.
Bioactive multifunctional hopeite coatings on new generation SS254 steel by laser rapid manufacturing for bone implant applications
Published in Transactions of the IMF, 2020
Bone-implants are largely being made of stainless steels (SS) despite their inferior corrosion resistance compared to titanium, mainly due to their admirable mechanical properties and low price.13,14 Recently, a new austenitic stainless steel SS254 (Fe = 55.69%, Cr = 20%, Ni = 18%, Mo = 6.1%, N = 0.20%, C = 0.010%) has been studied, largely owing to its non-toxic character and high nitrogen content which make it a potential contender for systematic examination, in developing an innovative orthopaedic implant material.15,16 This possible orthopaedic implant material is not biologically active; and there is concern to maintain structural strength and functional connection. To overcome these issues scientists have tried to alter the metallic implant topography and surface composition.17 In view of a desire to shorten the bone healing period and to increase the clinical success of metallic implants, various surface modification methods have been used.18 As reported previously in the literature a bioceramic coating can avert the toxic metal ions release from the implant surface into the environment.19 A new generation multifunctional bioceramic coating of hopeite (hydrated zinc phosphate) can check the release of toxic ions from the surface of SS254 and ensure overall better bioactivity, largely because of the presence of phosphate which is the key constituent of osteoconductive ceramics and of zinc which is a well-known element for improving biomineralisation.20–22 Hopeite (Zn3(PO4)2·4H2O) is a contender bio-implant material mainly used in dental implants; it can also promote bone growth.23,24 Hopeite formation offers low solubility, better adhesion, superior biocompatibility and excellent durability of dental cement.24–27 As reported in the previous literature, the hopeite layer effectively promotes hydroxyapatite (HA) re-growth in the simulated body fluid (SBF) environment.23,28 HA regrowth is credited to the high concentration of calcium and phosphorus ions, which provides a favourable condition for HA nucleation.29 Previously conducted research has confirmed the apatite formation on bioactive material’s surface in the SBF environment, while the bulk remains unaffected.30–39 Hopeite coating is therefore expected to improve the overall biological activity of metallic implants, including SS254.