Synthesis and application of water resistance and endurance silane coupling agents

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The cause of deterioration of the mechanical properties of composites is attributed to the hydrolysis of the silane-coupling layer between the inorganic silica filler, and the organic base resin. In order to improve the endurance of dental composites against hydrolysis, we have synthesized and studied silane coupling agents.Seven experimental composites were prepared, containing fillers, which were modified with either 3-methacryloyloxypropyltrimethoxysilane (3-MPS) or a mixture of 3-MPS and the hydrophobic fluoroalkyltrimethoxysilanes. They were subjected to water immersion for 1,800 days and the Thermal Cycling Test for 30,000 cycles. The composite specimen containing filler modified with a mixture of 3-MPS and methacryloyloxypropyltrimethoxysilane showed no significant on tensile strength. In contrast -MPS modified filler containing composite demonstrated significant decrease after water immersion period and thermal stress.To improve further water resistance of the polysiloxane laye … More r at the silica/resin interface, a mixture of 3-MPS and novel silane coupling agents (MAnbF, n=5,7,9,1) with a hydrophobic fluoroalkyl and methaclyloyl group (i. e. 3{[1'-(perfluoro-5-mathylhexy) methyl-2'-(methacryloyloxy9] ethoxy }propil-trimethoxysilane (MA7bF))were synthesized. The concentration of each silane solution was adjusted with ethanol at 2 mass%, at various weight ratios of MAnbF 10, 20, 30, 50, 70 and 100% to 3-MPS. The tensile bond strength of the resin composites were measured, as well the contact angles of resin monomer mixture to glass plates modified with each silane. MA5bF formed a coupling layer with high bond strength and high water resistance at the silica/resin interface in all concentrations studied. MA7bF, MA9bF and MA11bF formed these layers at concentrations within 10-30%.From the results obtained in this study, it was suggested that the surface modification of the silica with a MA5bF or a mixture of 3-MPS and nonafluorohexyltrimethoxysilane increase the water endurance of resin composite. Less