Thesis (Ph. D.)--Lehigh University, 2004. / Includes vita. Includes bibliographical references (leaves 113-119).

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 64-66). Also available via the Internet.

OBJECTIVES: To evaluate in vitro the coronal leakage of endodontically treated teeth sealed with temporary restorative materials with or without coating sealants, and subjected to brushing and thermocycling. MATERIALS AND METHODS: One hundred two extracted human premolars and molars, were endodontically accessed, and restored with 3 types of temporary restorations: 1. Cavit (3M ESPE), 2. Ketac Molar (3M ESPE), 3. Riva Light Cure GlC (SDI). Each type of restoration had one subgroup with a coating (Cavit-Ketac Glaze, Ketac Molar- Ketac Glaze, Riva Light Cure GIC – Riva Coat) and the other without coating. Restored teeth were placed in artificial saliva at 37°C for 24 hours. Teeth were divided into 3 treatment subgroups: Group A: No treatment, soaked at 37° C artificial saliva; Group B: Teeth underwent thermocycling; Group C: teeth underwent both thermocycling and brushing. Thermocycling included 500 cycles between 5°C to 55°C. Tooth brushing was simulated in a brushing machine using 190g weight applied to 16,800 linear strokes. The control group was not exposed to thermocycling or brushing. Leakage was detected by immersion of specimens in 2% methylene blue dye for 24 hours. Specimens were epoxy embedded and sectioned longitudinally. The leakage scores were evaluated from photographs by longitudinal dye penetration depth scored 0 for no leakage and 4 for maximum leakage to the bottom of restoration. Statistical analysis was done to examine the effect of coating and post-treatment on leakage scores. RESULTS: All tested temporary restorative materials with coating had lower leakage than without coating in all experimental groups. CONCLUSIONS: The leakage of temporary restorative materials can be reduced by surface coating, however, thermocycling and brushing treatment can still generate some leakage. / 2020-06-28T00:00:00Z

Investigations were carried out to assess the role of primer, pretreatments and coating microstructure in preventing cutedge corrosion of chrome free organically coated steels. Zinc runoff was monitored from a range of organically coated steels with a large cutedge length exposed over 18 months at Swansea University roof top site. The zinc in the runoff leaches from the zinc-aluminium alloy coating of the substrate. The paint systems' corrosion performance was assessed by monitoring the levels of zinc in the runoff. Consequently the levels of zinc reflected the effectiveness of the applied paint system against corrosion. Runoff was high in initial months with zinc levels reducing with time due to the build up of corrosion products that hindered the progress of corrosion. An accelerated laboratory test using a distilled water electrolyte was developed that predict long-term external weathering runoff from panels of a range of organically coated steels. The corrosion mechanisms of a variety of organically coated Galvalloy steel have been examined using the scanning vibrating electrode technique (SVET) in 0.1%NaCI. The corrosion behaviour of a coating is related to the zinc-aluminium alloy coating structure and combination of pretreatment and primer. The SVET has been used to assess total zinc loss and the corrosion rate for a comparative measure of organically coating system performance. A correlation has been developed from SVET 24hour experiment data to accelerated weathering data and external weather data that can aid more accurately predicting the in service life of the product. Also considered were the effects of electrolyte conductivity on the morphology of corrosion on pure zinc. A mathematical model has been developed to predict corrosion pit population. Altered microstructure of solidifying zinc aluminium alloy melt via ultrasonication was investigated. Ultrasound irradiation significantly altered the final microstructure. The influence of morphed microstructure upon the corrosion behaviour was explored using the SVET in 0.1%NaCI. The ultrasound manipulated microstructure had generally a positive effect on the corrosion behaviour.

Sustainability has been a driving factor in the recent development of protective coating systems, from reducing volatile organic compounds (VOC’s), integrating biomass for the replacement of petrochemicals, to reducing the number of synthetic or processing steps within a coating system. Incorporating changes to established technologies requires research initiatives focused on matching or exceeding performance properties while maintaining or lowering costs. As a result, sustainable changes to protective coating systems have been under heavy investigation as market demands shift from petrochemicals to renewable materials. This research focuses on the development of unique thermoset coating systems and sustainable improvements. The first study explores the hydrolytic stability between a silanol and an isocyanate, a frequently used reaction that has been relatively understudied. Incorporation of potential hydrolytically unstable silyl carbamates into polyurethane systems may decrease the crosslinking efficiency of the overall network, negatively impacting coating performance. As a result, investigation into the stability of silyl-carbamates may prevent further inefficiencies by eliminating use of this chemistry within polyurethane systems. The second study focuses on the development of alkoxysilane sol-gel consolidants for the protection of stone materials. Sustainable approaches to consolidant formulation include the reduction and elimination of solvent while improving consolidating properties through material selection. The last two studies focus on the incorporation of lignin-derived vanillin into epoxy thermosets and melamine formaldehydes, increasing the overall biobased content of each system. / Office of Naval Research (FAR0025712) / National Center For Preservation Technology and Training, NCPTT (FAR0028305) / EPSCoR/NSF (FAR0030160)

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