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Title:	Physico-mechanical and aging properties of denture basepoly (methyl methacrylate) filled with alumina micro- and nanoparticles
Authors:	Fathie A.M Kundie (P68624)
Supervisor:	Che Husna Azhari, Prof. Dr.
Keywords:	Aluminum oxide
Issue Date:	5-Feb-2018
Description:	This research investigated the effects of alumina (Al2O3) micro- and nanoparticles on poly(methyl methacrylate) (PMMA) denture base. The Al2O3 particles were surface treated with silane coupling agent (γ-MPS), which were then added to methyl methacrylate (MMA) and mixed with PMMA powder to form PMMA-Al2O3 composites. The filler loading in the microcomposites were 0.5, 1, 2, 5, and 7 wt%, whereas in the nanocomposites were 0.13, 0.25, 0.5, 1, 2, and 5 wt%, respectively. The surface characterisation of the treated fillers was examined using Fourier transform infrared spectroscopy (FTIR). The composites were then subjected to physico-thermo-mechanical properties of density, radiopacity, thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), fracture toughness, flexural tests and surface hardness. The environmental properties were investigated using water absorption and solubility. The Effects of filler size and volume fraction to these properties were also carried out, which were related to the morphology using electron microscopy. Results of the surface characterisation from FTIR spectra confirmed the successful Al2O3 surface modification. The prepared composites and control samples showed no change in density. The microcomposites were more opaque than nanocomposites. Thermal testing showed that the microcomposites exhibited higher thermal stability than nanocomposites. Observations of the mechanical testing showed fracture toughness increased with the addition of both micro- and nanoscale filler particles. The highest fracture toughness value was attained at 0.5 wt% nano-Al2O3 filler loading, while that of the microcomposite showed the highest value at 2 wt% micro-Al2O3 filler loading. The improvement in fracture toughness can be attributed to the good dispersion of the filler in the PMMA matrix and the incorporation of high-strength fillers and silanation. In contrast to the flexural strength, the flexural modulus improved with increasing filler loading. Increasing the amount of the micro- and nano-Al2O3 fillers decreased the flexural strength; this could be explained by the presence of agglomerates and voids, which are initiating factors for failure. The samples filled withAl2O3 microparticlesshowed the highest surface hardness values compared to the nanoparticles. The water absorption of micro- and nanocomposites were slightly higher than those of the pure PMMA. This could be attributed to the presence of soluble impurities, interfacial properties, and air voids may be introduced in the composites during mixing. In addition, microvoids are formed during polymerisation and due to leaching of unreacted monomers, plasticisers, and initiators. The water solubility of micro- and nanocomposites were also slightly higher than those of the PMMA matrix. This could be assigned to the dependence of water solubility on the filler particle size and distribution, homogeneity of the composite and due to leaching of residual monomers, plasticisers, and initiators.,Ph.D.
Pages:	170
Call Number:	TP245.A4K836 2018 3 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina

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