In this paper, the mechanical and morphological properties of biodegradable SAN/EOC/Nanoclay/Proteins nanocomposite were investigated. The composites were first prepared by a laboratory-scale twin screw extruder. Morphology of the blend was determined by SEM images. Mechanical properties in terms of tensile tests were carried out by Testometric TS2000, stress at break, strain at break, and Young’s modulus was determined. Based on mechanical results, although the young’s modulus increases with increasing protein content but the strain at break of the composite decreases acutely because of the presence of protein. The blend indicated an improvement in mechanical and thermal properties. Today, according to the vast application of plastic in different fields, environmental issues were affected by these kinds of non-degradable materials, so that biodegradability of the plastics is just the remaining route to solve. In this research, biodegradable blends were prepared using whey protein as a biodegradable natural polymer. The results of the biological procedure-test after 3 months indicated sufficient weight loss and biodegradation of these blends.
This study was aimed at fabricating and evaluating the physical and bioproperties of nanofast cement (NFC) as a replacement of the MTA. The cement particles were decreased in nanoscale, and zirconium oxide was used as a radiopacifier. The setting time and radiopacity were investigated according to ISO recommendations. Analysis of color, bioactivity, and cytotoxicity was performed using spectroscopy, simulated body fluid (SBF), and MTT assay. The setting time of cement pastes significantly dropped from 65 to 15 min when the particle sizes decreased from 2723 nm to 322 nm. Nanoparticles provide large surface areas and nucleation sites and thereby a higher hydration rate, so they reduced the setting time. Based on the resulting spectroscopy, the specimens did not exhibit clinically noticeable discoloration. Resistance to discoloration may be due to the resistance of zirconium oxide to decomposition. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and infrared spectroscopy (FTIR) examinations of the immersed SBF samples showed apatite formation that was a reason for its suitable bioactivity. The results of cell culture revealed that NFC is nontoxic. This study showed that NFC was more beneficial than MTA in dental restorations.
Hydroxyapatite (HA) can be used as a bioceramic due to its bioactivity and osteoconductive properties. It is clear that the morphology of HA crystal affects on its specifications such as surface and bioactivity. Because of importance of morphology, in the current research nanosized HA particles were produced using sol-gel and precipitation methods, and to change the morphology, polyethylene glycol (PEG) was used as an organic modifier. The produced samples were characterized using X-ray powder diffraction (XRD) and scanning electron microscopy and transmission electron microscopy. The results of XRD patterns show that the pure HA can be produced using two methods. Microscopic evaluations prove that the presence of PEG has a significant effect on HA morphology. Indeed, PEG changes the morphology of HA produced by precipitation method to irregular, whereas in sol-gel method its shape leads toward fibrous with high aspect ratio. The exact reason of this variation can be attributed to the difference in mechanism of HA growth in two methods. Graphical Abstract & S. Mojtaba Zebarjad
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