Engineering and Technology Journal

In the present research, study the effect of adding two different types of reinforcing particles, which included: nano-alumina (nano-Al2O3) and nano-silica (nano-SiO2), that added with different volume fractions of (1%, 2% and 3%), on some physical properties of composite prosthesis complete denture base materials by using self (cold) cure poly methyl methacrylate (PMMA) resin as new fluid resin matrix. In this research, the composite prosthetic dentures specimens consist of two groups were prepared by using (Hand Lay-Up) method according to the types of reinforced particles, which includes: the first group consists of PMMA resin reinforced by nano-alumina particles, and the second group consists of PMMA resin reinforced by nano-silica particles. The physical tests were performed on these specimens include (water absorption test and thermal behaviors test). The result of this study showed the values of (thermal conductivity and thermal diffusivity) properties increased with increasing the volume fraction of both (nano-Al2O3 and nano-SiO2) particles in PMMA complete denture base materials. While, the values of (water absorption and specific heat) properties decreased. In addition, the addition of (nano-Al2O3) particles has a noticeable effect on the all properties of composite material for prosthetic denture base specimens more than the (nano-SiO2) particles.

In this research polymer blend was prepared from (EP-Novolac) reinforced by ceramic particles (SiC), which added as (10%, 20%, 30%) Wt to the blend, by using hand lay-up method
Some mechanical properties were studied on the specimens of the above mentioned materials such as hardness and wear, at different temperatures and immersion times, The samples were immersed in (HCL) and (NaOH) solutions with normality (0.5 N) for (2 and 4) weeks at different temperature (25 ,44, 62) ˚C
And then the results of the reinforced blend showed decreasing of hardness values after immersion samples in to both above solutions
It is found that in spite of there is increment in temperatures and immersion times in (NAOH) that is consider as a corrosion media to polymers there is decreases in wear rate specially at percentage (30%Sic).

Corrosion behavior of pure Al and Al/ Al2O3 composite with five weight percent of Al2O3 particles (5,10,15,20 and 25) were investigated in 0.1M H2SO4 and 3.5 % NaCl solutions at room temperature. The composites were prepared by powder metallurgy and their corrosion behavior were evaluated by potentiostatic polarization and scan rate 3mV.sec-1.
It's observed that pure Al/Al2O3 composites exhibited excellent corrosion resistance in NaCl medium than in the H2SO4 media. The pure aluminum exhibited slightly superior corrosion resistance than the composites in NaCl medium but the composites had better corrosion resistance in H2SO4 medium.
Insulator Al2O3 particles are perceived to act as inert material and degrade the integrity of the protective oxide layer on the Al matrix.
Al/Al2O3 composites have lower corrosion rate than pure aluminum in 0.1 M H2SO4, but increasing of wt% of alumina led to increase the corrosion rate. While in 3.5% NaCl solution can be seen that corrosion rate of pure aluminum less than that for composites. Generlly, For certain material, the corrosion rate in salt medium less than in acidic medium.

Tellurium dioxide (TeO2) nanoparticles were synthesized directly by pulsed laser ablation using Nd:YAG, λ=1064nm laser in pure water. The AFM and XRD measurements, in combination with FTIR and UV–Vis spectroscopy have been employed for the characterization of the prepared samples. The effects of operating parameters on nanoparticles composition, production rate and size were also studied. The XRD measurements revealed crystallization structure of TeO2 nanoparticles. The particle diameter by use of Scherer's equation was calculated to be about 28. nm and confirmed by AFM measurements. The UV–vis spectrum of the colloidal nanoparticles shows maximum absorbance around the UV region, indicating the formation of TeO2 nanoparticles, which confirmed by FTIR.