16610

16610

ساخت و بررسي خواص كامپوزيت پايه پلي بنزوكسازين تقويت شده با نانو ذرات سراميكي با كاربرد دندانپزشكي

كارشناسي ارشد

مهندسي پزشكي - بيومتريال

خرداد ماه 1395

دكتر جعفرجوادپور - دكتر محمدرضا نعيمي جمال

مواد ومتالورژي

1395/11/25

1/1/1900 12:00:00 AM

Abstract: The biological an​d mechanical properties of substances are relevant to their application as dental materials an​d tissue engineering scaffolds. To achieve a low rate of shrinkage during polymerization, good mechanical properties, an​d excellent biocompatibility, benzoxazine monomer was synthesized using a solventless method. FTIR an​d DSC analysis were carried out to determine the appropriate polymerization temperature of the benzoxazine monomer. The low viscosity of the benzoxazine monomer at 70°C required in situ polymerization after high speed ball milling of the benzoxazine an​d it mixture with different weight fractions of zirconia particles. SEM images showed good dispersion an​d adhesion between the ceramic an​d polymer components. To eva​luate the biological properties an​d toxicity of the polybenzoxazine-based composites reinforced with zirconia particles, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay was carried out. The results of the assay showed excellent in vitro biocompatibility of the composites. The micromechanical properties of each composite were eva​luated by more than 20 nanoindentation tests an​d 3 nanoscratching tests. Surface topography of scratched regions was investigated using Atomic Force Microscopy. Nano indentation force-displacement curves showed matrix, reinforcement an​d interphase regions in specimens an​d excellent homogeneity in mechanical properties. The nanoindentation results showed that the addition of zirconia particles to the polybenzoxazine matrix increased the modulus an​d hardness of the neat polybenzoxazine; however, after reaching an optimum level, the mechanical properties of the composites decreased because of agglomeration of the reinforcement particles an​d the weak interface between ceramic an​d polymer particles. Results of nano-scratching tests showed effects of zirconia particles as reinforcement on the coeffiecient of friction of the synthesized composites. Shrinkage was simulated by Materials Studio software an​d showed a low rate of shrinkage for polybenzoxazine in comparison with other low shrinkage biomaterials, such as Bis-GMA. Keywords: Polybenzoxazine; Biocomposites; Zirconia; Nanoindentation; Biocompatibility