Large-scale fabrication of SiC nanofibers and plasma interface engineering of polymer nanocomposites and dental composite restoration
Abstract
[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] SiC nanofibers in gram-scale per batch were synthesized by chemical vapor deposition. A systematic comparison of different sized graphite and multi-walled carbon nanotubes as carbon precursors of SiC nanofibers revealed Ni catalyst concentration significantly affected the quality of growth. The size of the carbon precursor affected the kinetics and diffusion, which effect the SiC nanofiber growth as observed in electron microscopy. Allylamine plasma surface treated MWNTs and SiC nanofibers enhanced dispersion and interfacial adhesion in an epoxy matrix. All composite samples without plasma treatment lowered in tensile strength, but after plasma treatment all samples increased the tensile strength by 40%. Nanomaterial settling and aggregation were observed with composites using untreated samples and was believed to negatively affect the mechanical properties. The increase in strength of plasma treated samples was attributed to enhanced dispersion and interfacial adhesion observed visually and by electron microscopy. A non-thermal argon plasma brush treatment increased the micro-tensile strength of dental composite restorations. FTIR observed an increase in carbonyl groups on the surface of plasma treated demineralized dentin. The increase in tensile strength was attributed to improved adhesive penetration into collagen fibrils and increased hydrogen bonding between dental adhesive and dental collagen
Degree
Ph. D.
Thesis Department
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