A master’s student, Hussein M. S. Jaafar, defended his thesis “Development of Hybrid Polymer Blend Composite Used in Dentures Fabrication” on Wednesday, January 15^th, at the conference room (C), Department of Materials Engineering, University of Technology. The Committee members included:

The dissertation was scientifically evaluated by Ass. Prof. Dr. Ahmed F. Ali, Babylon University, College of Materials Engineering, and linguistically by Ass. Prof. Mayada R. Issa, University of Technology, English Language Center.

The discussion was conducted in a scientific atmosphere and a master's degree with grade of pass was awarded to the student after the completion of all the corrections that have been decided by the examiners.

Abstract

      The aim of this study is to develop the properties of PMMA prepared by heat treatment through the manufacturing of bio composites materials that, consist of a polymer blends (PMMA: X% NR or SR where x=2% or 3%) as matrix materials reinforced by two types of natural nanoparticles (  pomegranate peels powder (PPP) and clove powder (CP))  used individually with selected weight percentages (0.0, 0.1, 0.3, 0.5, 0.7%) in PMMA composites.  

      Based on the results of mechanical properties for bio composites samples, one sample was selected as an optimal sample of nanocomposites samples (PMMA: 2%NR: 0.7%PPP)), that was used to prepare hybrid composites specimens, which was reinforced at 0.75% weight ratio of nylon fibers in the form of (mono-filament and multifilament fiber). All samples were fabricated by utilizing (Hand Lay-Up) technique.

       The biological activity test was done on composites samples to make sure from the biological effect for both of natural particles (PPP and CP) and nylon fibers. AFM inspection was done in order to measure the average size of natural particles and average diameter of nylon fibers. In addition to studying the analysis of FTIR spectra and structure morphology by SEM for the prepared composites.

       The experimental part of this study include performing many mechanical tests which involve: tensile strength, compression strength, flexural strength, flexural strain, hardness, impact strength, fracture toughness, wear resistance and surface roughness. In addition to the physical properties that involve: thermal conductivity, density, water absorption and contact angle for all the prepared specimens. The results showed that using various kinds of natural nanofillers as reinforcing materials had a considerable effect on the characteristic of base dentures which were prepared. As well as observed that the values of most properties increased with increasing content ratios of both types pomegranate peels powder and clove powders in bio composite specimens. On the other hand, the values of surface roughness, contact angle, wear rates and density values ​​of all prepared samples decreased with adding of natural nano-filler materials. Also, the results have shown that the values of all mechanical for bio composite reinforced with pomegranate peels powder higher than that reinforced with clove powder and reached to the maximum values at 0.7% of the percentages weight of pomegranate peel powder. Moreover, the properties of hybrid bio composite increased when reinforced with multifilament nylon fiber, that have the higher values as compared with that reinforced by mono-filament fiber. furthermore, from  the analysis of infrared spectra it was observed that is no shifting in peaks of characteristic frequencies of bio nanocomposites, relative to those spectra of polymer blend and neat PMMA, this indicates the occurrence of physical bonds and the absence from any chemical reactions or cross linking that may occur as a result of the mixing process. Moreover, the morphological analysis results indicated a good interfacial adhesion between all constituents of composite materials, especially those reinforced by PPP nanoparticle. to put it another way, this indicated to a perfect compatibility between the constituents of polymer blend and the natural nanoparticles (PPP or CP) and nylon fiber, which led to enhance the mechanical properties.