Saman Mahdavi - Institute of Polymeric Materials, Polymer Engineering Department, Sahand University of Technology, P.O. Box: ۵۱۳۳۵-۱۹۹۶, Tabriz, Iran
Mostafa Rezaei

Whereas application of orthopedic bone cements raise dramatically during the last decade, improving its properties strongly seems necessary. Generally, commercial bone cements are made from brittle polymethyl methacrylate (PMMA). Physical and mechanical properties of PMMA- Montmorillonite (MMT) organoclay (Cloisite 30B) nanocomposites bone cement were considered in this study. MMT organoclay (0.25, 0.5, 1 and 2 wt%) was dispersed on the MMA monomer solution ultrasonically and then was added to the powder components of the bone cement to prepare the samples. X-ray diffraction (XRD) patterns were used to study the dispersion state of nanoclays in PMMA matrix. There was no characteristic peak in XRD patterns in the scan range of 2-10° which can be attributed to the partially intercalation or exfoliation of nanoclays in PMMA. This result was confirmed comparing of transmission electron microscopy (TEM) image. Differential scanning calorimetry (DSC) results illustrated decreasing of glass transition temperature by incorporation of nanoclays to the bone cement. Considering thermal gravimetric analysis (TGA) results approved that the higher contents of organoclay increase the thermal stability of nanocomposites. Furthermore tensile results for MMT organoclay nanocomposite bone cement indicated higher Young modulus and tensile strength. Linear elastic fracture mechanics (LEFM) was used in compact-tension (CT) tests and the CT results showed higher fracture toughness (KI) for organoclay incorporated nanocomposite at 0.5 wt% compare to the other samples. Morphological studies were conducted by scanning electron microscopy (SEM). The SEM results of the fractured surfaces confirmed the increasing in porosity of nanocomposite bone cements compared to the neat bone cement.

LEFM, Bone Cement, Clay Nanocomposite, Fracture