Self-Healable Supramolecular Vanadium Pentoxide Reinforced Polydimethylsiloxane-Graft-Polyurethane Composites.

The self-healing ability can be imparted to the polymers by different mechanisms. In this study, self-healing polydimethylsiloxane-graft-polyurethane (PDMS-g-PUR)/Vanadium pentoxide (V2O5) nanofiber supramolecular polymer composites based on a reversible hydrogen bonding mechanism are prepared. V2O5 nanofibers are synthesized via colloidal route and characterized by XRD, SEM, EDX, and TEM techniques. In order to prepare PDMS-g-PUR, linear aliphatic PUR having one ⁻COOH functional group (PUR-COOH) is synthesized and grafted onto aminopropyl functionalized PDMS by EDC/HCl coupling reaction. PUR-COOH and PDMS-g-PUR are characterized by ¹H NMR, FTIR. PDMS-g-PUR/V2O5 nanofiber composites are prepared and characterized by DSC/TGA, FTIR, and tensile tests. The self-healing ability of PDMS-graft-PUR and composites are determined by mechanical tests and optical microscope. Tensile strength data obtained from mechanical tests show that healing efficiencies of PDMS-g-PUR increase with healing time and reach 85.4 ± 1.2 % after waiting 120 min at 50 °C. The addition of V2O5 nanofibers enhances the mechanical properties and healing efficiency of the PDMS-g-PUR. An increase of healing efficiency and max tensile strength from 85.4 ± 1.2% to 95.3 ± 0.4% and 113.08 ± 5.24 kPa to 1443.40 ± 8.96 kPa is observed after the addition of 10 wt % V2O5 nanofiber into the polymer.

[Production and characterization of a glass-ceramic biomaterial and in vitro and in vivo evaluation of its biological effects]. / Bir cam-seramik biyomalzemenin üretimi, tanimlanmasi ve biyolojik etkilerinin canli-disi ve canli-içi ortamda degerlendirilmesi.

OBJECTIVES: Glass-ceramics are biomaterials that are usually produced by the sol-gel technique and can be used as a substitute for bone. One important feature of glass-ceramics is osteointegration with bone tissue. This study was designed to produce a glass-ceramic and evaluate its structure and in vitro and in vivo biological effects. METHODS: With the sol-gel method, a glass-ceramic was synthesized in the form of 30SiO2-17MgO-53Ca3(PO4)2 using tetraethylorthosilicate, dibutyl phosphate, magnesium, and calcium nitrate. Glass-ceramic jel samples were sintered at temperatures up to 1100 degrees C and their microstructure and phases were examined by the X-ray diffraction (XRD) technique and scanning electron microscopy. For in vitro tests, the samples were immersed in a simulative body fluid (SBF) for 10, 30, and 40 days to be analyzed by XRD. For in vivo tests, the samples were placed in tibial metaphyses of Sprague-Dawley rats for 4, 6, and 8 weeks for histological evaluation of osteointegration. RESULTS: As the temperature increased, growth of crystal phases was noted. While XRD analysis showed no change in samples that were kept in SBF for 10 days, hydroxyapatite crystals were seen after 30 and 40 days of SBF treatment in the second and third degree of crystal phases. In vivo test results showed that the glass-ceramic possessed a high tendency to replace osteoid bone tissue, with full osteointegration at eight weeks. CONCLUSION: The glass-ceramic produced has a high surface reactivity and can be used as a bone substitute material.