Current Search: Polymeric composites (x)
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- Title
- Low velocity impact and compression after impact characterization of woven carbon/vinylester at dry and water saturated conditions.
- Creator
- Dale, Michael, Acha, Betiana A., Carlson, Lief, Graduate College
- Date Issued
- 2011-04-08
- PURL
- http://purl.flvc.org/fcla/dt/3164519
- Subject Headings
- Polymers, Polymeric composites, Accelerometers
- Format
- Document (PDF)
- Title
- Synthesis and structural characterization of organotin and group IVB metallocene dichlorides with kinetin.
- Creator
- Chamely-Wiik, Donna M., Florida Atlantic University, Carraher, Charles E.
- Abstract/Description
-
Metal containing polymers were synthesized by reaction of organotin and group IVB metallocene dichlorides with kinetin, a plant growth hormone (PGH), via the interfacial polycondensation process. Product yields were in the range of 40--63% and degrees of polymerization were from 20 to 150. The structures of the products were determined using infrared and mass spectroscopy. Further characterization involved determination of solubility, degree of polymerization and electrical conductivity. The...
Show moreMetal containing polymers were synthesized by reaction of organotin and group IVB metallocene dichlorides with kinetin, a plant growth hormone (PGH), via the interfacial polycondensation process. Product yields were in the range of 40--63% and degrees of polymerization were from 20 to 150. The structures of the products were determined using infrared and mass spectroscopy. Further characterization involved determination of solubility, degree of polymerization and electrical conductivity. The biological potential of the products was tested against selected microorganisms and Balb/3T3 cell lines. One of the products showed activity in the 0.2mug/ml range, one hundredth of that of similar compounds. Germination experiments using the PGH incorporated polymers were performed on sawgrass and cattail seeds as well as selected vegetable seeds and compared to a control. Sawgrass germination, typically in the 0--2% range were increased to about 60% through the treatment with kinetin-containing polymers.
Show less - Date Issued
- 2000
- PURL
- http://purl.flvc.org/fcla/dt/12675
- Subject Headings
- Polymeric composites, Organotin compounds, Plant hormones
- Format
- Document (PDF)
- Title
- Mechanical properties of fiber-reinforced polymer (FRP) composites for concrete bridge deck reinforcement.
- Creator
- Manav, Mukbil Ozan., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
-
Durability of concrete bridge decks reinforced with conventional structural steel is a major concern in aggressive environments. To address this problem, there have been efforts, in recent years, to develop and evaluate alternatives to conventional steel. One alternative is fiber reinforced polymer (FRP) composite reinforcement. FRP composites have been used successfully in many industrial applications. This thesis investigates short-term mechanical properties of FRP rebars as reinforcement...
Show moreDurability of concrete bridge decks reinforced with conventional structural steel is a major concern in aggressive environments. To address this problem, there have been efforts, in recent years, to develop and evaluate alternatives to conventional steel. One alternative is fiber reinforced polymer (FRP) composite reinforcement. FRP composites have been used successfully in many industrial applications. This thesis investigates short-term mechanical properties of FRP rebars as reinforcement for concrete bridge decks and discusses results of extensive laboratory tests. Four test methods (tension, flexure, shear and bond) are developed and test protocols are proposed for adoption by AASHTO.
Show less - Date Issued
- 2002
- PURL
- http://purl.flvc.org/fcla/dt/12988
- Subject Headings
- Fibrous composites--Mechanical properties, Polymeric composites, Reinforced concrete, Fiber
- Format
- Document (PDF)
- Title
- Determination of the tensile strength of the fiber/matrix interface for glass/epoxy & carbon/vinylester.
- Creator
- Totten, Kyle, Carlsson, Leif A., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The tensile strength of the fiber/matrix interface was determined through the development of an innovativetest procedure.Aminiature tensile coupon with a through-thickness oriented, embedded single fiberwas designed. Tensile testing was conducted ina scanning electron microscope (SEM)while the failure process could be observed.Finite element stress analysis was conducted to determine the state of stressat the fiber/matrix interface in the tensile loaded specimen, and the strength of the...
Show moreThe tensile strength of the fiber/matrix interface was determined through the development of an innovativetest procedure.Aminiature tensile coupon with a through-thickness oriented, embedded single fiberwas designed. Tensile testing was conducted ina scanning electron microscope (SEM)while the failure process could be observed.Finite element stress analysis was conducted to determine the state of stressat the fiber/matrix interface in the tensile loaded specimen, and the strength of the interface.Test specimensconsistingof dry E-glass/epoxy and dry and seawater saturatedcarbon/vinylester510Awere preparedand tested.The load at the onset of debondingwascombined withthe radial stressdistributionnear thefree surface of the specimento reducethe interfacial tensile strength. For glass/epoxy, was 36.7±8.8MPa.For the dryand seawater saturated carbon/vinylester specimensthetensilestrengthsof the interface were 23.0±6.6 and 25.2±4.1MPa, respectively.The difference is not significant.
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00004415, http://purl.flvc.org/fau/fd/FA00004415
- Subject Headings
- Composite materials -- Mechanical properties, Composite materials -- Testing, Fibrous composites -- Mechanical properties, Polymeric composites -- Mechanical properties, Viscoelasticity
- Format
- Document (PDF)
- Title
- Effects of Carbon Nanotube (CNT) Dispersion and Interface Condition on Thermo-Mechanical Behavior of CNT-Reinforced Vinyl Ester.
- Creator
- Sabet, Seyed Morteza, Mahfuz, Hassan, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
In fabrication of nanoparticle-reinforced polymers, two critical factors need to be taken into account to control properties of the final product; nanoparticle dispersion/distribution in the matrix; and interfacial interactions between nanoparticles and their surrounding matrix. The focus of this thesis was to examine the role of these two factors through experimental methodologies and molecular-level simulations. Carbon nanotubes (CNTs) and vinyl ester (VE) resin were used as nanoparticles...
Show moreIn fabrication of nanoparticle-reinforced polymers, two critical factors need to be taken into account to control properties of the final product; nanoparticle dispersion/distribution in the matrix; and interfacial interactions between nanoparticles and their surrounding matrix. The focus of this thesis was to examine the role of these two factors through experimental methodologies and molecular-level simulations. Carbon nanotubes (CNTs) and vinyl ester (VE) resin were used as nanoparticles and matrix, respectively. In a parametric study, a series of CNT/VE nanocomposites with different CNT dispersion conditions were fabricated using the ultrasonication mixing method. Thermomechanical properties of nanocomposites and quality of CNT dispersion were evaluated. By correlation between nanocomposite behavior and CNT dispersion, a thermomechanical model was suggested; at a certain threshold level of sonication energy, CNT dispersion would be optimal and result in maximum enhancement in properties. This threshold energy level is also related to particle concentration. Sonication above this threshold level, leads to destruction of nanotubes and renders a negative effect on the properties of nanocomposites. In an attempt to examine the interface condition, a novel process was developed to modify CNT surface with polyhedral oligomeric silsesquioxane (POSS). In this process, a chemical reaction was allowed to occur between CNTs and POSS in the presence of an effective catalyst. The functionalized CNTs were characterized using TEM, SEM-EDS, AFM, TGA, FTIR and Raman spectroscopy techniques. Formation of amide bonds between POSS and nanotubes was established and verified. Surface modification of CNTs with POSS resulted in significant improvement in nanotube dispersion. In-depth SEM analysis revealed formation of a 3D network of well-dispersed CNTs with POSS connections to the polymer. In parallel, molecular dynamics simulation of CNT-POSS/VE system showed an effective load transfer from polymer chains to the CNT due to POSS linkages at the interface. The rigid and flexible network of CNTs is found to be responsible for enhancement in elastic modulus, strength, fracture toughness and glass transition temperature (Tg) of the final nanocomposites.
Show less - Date Issued
- 2016
- PURL
- http://purl.flvc.org/fau/fd/FA00004628, http://purl.flvc.org/fau/fd/FA00004628
- Subject Headings
- Carbon nanotubes., Carbon composites., Polymeric composites., Fibrous composites, Nanostructured materials., Composite materials--Mechanical properties.
- Format
- Document (PDF)
- Title
- Durability of carbon fiber/vinylester composites subjected to marine environments and electrochemical interactions.
- Creator
- Hasnine, Md., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Degradation of the Carbon Fiber/Vinylester (CF/VE) polymer matrix composites due to different electrochemical interactions when exposed to seawater or at high temperature had been experimentally investigated. Water uptake behavior of composite specimen was examined based on weight gain measurement. Three point bending test was performed to quantify the mechanical degradation of composite immersed in seawater with different environmental and electrochemical interactions. Finally,...
Show moreDegradation of the Carbon Fiber/Vinylester (CF/VE) polymer matrix composites due to different electrochemical interactions when exposed to seawater or at high temperature had been experimentally investigated. Water uptake behavior of composite specimen was examined based on weight gain measurement. Three point bending test was performed to quantify the mechanical degradation of composite immersed in seawater with different environmental and electrochemical interactions. Finally, Electrochemical Impedance Spectroscopy (EIS) was used to better understanding of the degradation process in CF/VE composite produced by interactions between electrochemical and different environmental conditions. A detailed equivalent circuit analysis by using EIS spectra is also presented in an attempt to elucidate the degradation phenomenon in composites.
Show less - Date Issued
- 2010
- PURL
- http://purl.flvc.org/FAU/2683124
- Subject Headings
- Composite materials, Mechanical properties, Fibrous composites, Structural analysis, Polymeric composites, Spectrum analysis
- Format
- Document (PDF)
- Title
- Evaluation of Water Degradation ofPolymer Matrix Composites by Micromechanical and Macromechanical Tests.
- Creator
- Ramirez, Felipe A., Carlsson, Leif A., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Degradation of the critical components of polymer matrix composites in marine environments had been experimentally investigated. Water absorption behavior of neat resin and composite specimens was examined. The tensile strength of fibers was monitored using the single filament test. The mechanical properties of the resins were monitored by tensile, flexure, and dynamic-mechanical tests. In addition, matrix shrinkage during cure and matrix swelling after immersion in water were monitored. The...
Show moreDegradation of the critical components of polymer matrix composites in marine environments had been experimentally investigated. Water absorption behavior of neat resin and composite specimens was examined. The tensile strength of fibers was monitored using the single filament test. The mechanical properties of the resins were monitored by tensile, flexure, and dynamic-mechanical tests. In addition, matrix shrinkage during cure and matrix swelling after immersion in water were monitored. The integrity of the fiber/matrix (F/M) interface of the composite systems was studied using the single fiber fragmentation test (SFFT). Macroscopic composites were examined using transverse tensile and transverse flexure tests to study the influence of the integrity of the matrix and F/M interface on the macroscopic response. In addition, for characterization of F/M debonding in the SFFT, a fracture mechanics model and modified test procedure were developed.
Show less - Date Issued
- 2008
- PURL
- http://purl.flvc.org/fau/fd/FA00012543
- Subject Headings
- Composite materials--Mechanical properties, Polymeric composites--Testing, Fibrous composites--Testing, Polymers--Deterioration
- Format
- Document (PDF)
- Title
- Application of electrochemical impedance spectroscopy as a non-destructive technique to characterize and detect degradation of carbon/nylon, 6 composites in aqueous environments.
- Creator
- Haniyur, Ravishankar V., Florida Atlantic University, McIntyre, Jack F.
- Abstract/Description
-
Experiments were conducted to investigate the degradative effects of ambient and high pressure aqueous environments on unidirectional carbon fiber nylon (AS4/nylon 6) composites. Electrochemical impedance spectroscopy (EIS) was selected for development as a non-destructive method to characterize the degradation phenomena in carbon/nylon composites as result of moisture absorption. EIS data was collected for composites and neat resins as a function of immersion time in ambient and pressurized ...
Show moreExperiments were conducted to investigate the degradative effects of ambient and high pressure aqueous environments on unidirectional carbon fiber nylon (AS4/nylon 6) composites. Electrochemical impedance spectroscopy (EIS) was selected for development as a non-destructive method to characterize the degradation phenomena in carbon/nylon composites as result of moisture absorption. EIS data was collected for composites and neat resins as a function of immersion time in ambient and pressurized (6.2 MPa) 3.5% NaCl solution. EIS was also utilized to understand degradative mechanisms when composites were subject to cathodically induced damage. Concurrent EIS and 3-point mechanical loading was also performed on composites to study the changes in the impedance response as a function of loading. A detailed equivalent circuit analysis is also presented in an attempt to elucidate the degradation phenomena in composites. Gravimetric and 3-point mechanical testing data is also presented to study the effect of ambient and pressurized aqueous environments on composites. Scanning electron micrographs of composites are also included to assist in morphological evaluation.
Show less - Date Issued
- 1993
- PURL
- http://purl.flvc.org/fcla/dt/14907
- Subject Headings
- Impedance spectroscopy, Composite materials, Polymeric composites, Absorption, Environmental degradation--Moisture
- Format
- Document (PDF)
- Title
- Electrochemical impedance spectroscopy to monitor degradation of carbon fiber reinforced polymer composites subjected to simulated ocean environment.
- Creator
- Ahmed, Mohammad Mesbahuddin., Florida Atlantic University, Lipka, Stephen M.
- Abstract/Description
-
This research evaluated the applicability of electrochemical impedance spectroscopy (EIS) as a non-destructive technique to predict and characterize the degradation of carbon fiber reinforced polymer (CFRP) composites exposed to aqueous environments at ambient and 6.2 $\pm$ 0.3 MPa. Changes in EIS data were related to water uptake into the composite material as a function of exposure time. Electrochemically induced damage (both anodic and cathodic) were also evaluated using impedance...
Show moreThis research evaluated the applicability of electrochemical impedance spectroscopy (EIS) as a non-destructive technique to predict and characterize the degradation of carbon fiber reinforced polymer (CFRP) composites exposed to aqueous environments at ambient and 6.2 $\pm$ 0.3 MPa. Changes in EIS data were related to water uptake into the composite material as a function of exposure time. Electrochemically induced damage (both anodic and cathodic) were also evaluated using impedance measurements. Three point flexure tests with concurrent EIS measurements were employed to study the effect of stresses on water uptake and mechanical degradation. Visual observation of the extent of damage (i.e., fiber-matrix debonding) was made using scanning electron microscopy (SEM) and correlated with EIS observation.
Show less - Date Issued
- 1993
- PURL
- http://purl.flvc.org/fcla/dt/14962
- Subject Headings
- Polymers--Deterioration, Composite materials--Environmental aspects, Carbon fibers, Polymeric composites, Spectrum analysis
- Format
- Document (PDF)
- Title
- Flexible Filler Corrosion Protection of Unbonded Post-Tension Tendons.
- Creator
- Castaneda, Carlos F., Presuel-Moreno, Francisco, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Flexible fillers has recently been implemented as corrosion protection for post-tensioning tendons used in bridge structures in Florida. There are two different explanations why corrosion could take place: 1. water is able to reach the steel 2. Microbiologica l ly Influenced Corrosion. The aim of this research is to evaluate corrosion protection effectiveness of five differe nt microcrystalline waxes under different environmental conditions. Specimens tested ranged from 7-wire steel strands...
Show moreFlexible fillers has recently been implemented as corrosion protection for post-tensioning tendons used in bridge structures in Florida. There are two different explanations why corrosion could take place: 1. water is able to reach the steel 2. Microbiologica l ly Influenced Corrosion. The aim of this research is to evaluate corrosion protection effectiveness of five differe nt microcrystalline waxes under different environmental conditions. Specimens tested ranged from 7-wire steel strands to single wires (12-16 cm). Another aim is the appraisal of wax degradation by fungi species. Single wires coated with each of the investigated protection materials, were sprayed with suspensions of three different fungi species and a mix of them. For single wires, independent of the environmental condition the specimen with more corrosion was Nontribos, as well as the filler coated wires contaminated with Fungi. Fungi species investigated were able to utilize the waxes as carbon source and caused differe nt extents of MIC.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004924, http://purl.flvc.org/fau/fd/FA00004924
- Subject Headings
- Nanocomposites (Materials), Polymeric composites., Post-tensioned prestressed concrete., Tendons (Prestressed concrete)
- Format
- Document (PDF)
- Title
- Initial evaluation of organotin monomers and polymers as potential anticancer agents.
- Creator
- Doucette, Randy D., Florida Atlantic University, Louda, Deborah W.
- Abstract/Description
-
A large number of metal-containing compounds show significant activity against cancer cells and incorporating a metal into a polymer offers several possible advantages. Compounds of the type R2SnCl2 (R = methyl, ethyl, propyl, butyl, t-butyl, octyl and phenyl) were tested for the ability to inhibit the growth of Balb 3T3 mouse fibroblast cells and CAOV3 human ovarian carcinoma cells. Polymers of 2-chloro-1,4-benzenediamine and the same organotin dichloride were synthesized and tested as well....
Show moreA large number of metal-containing compounds show significant activity against cancer cells and incorporating a metal into a polymer offers several possible advantages. Compounds of the type R2SnCl2 (R = methyl, ethyl, propyl, butyl, t-butyl, octyl and phenyl) were tested for the ability to inhibit the growth of Balb 3T3 mouse fibroblast cells and CAOV3 human ovarian carcinoma cells. Polymers of 2-chloro-1,4-benzenediamine and the same organotin dichloride were synthesized and tested as well. For both monomers and polymers, the pattern of growth inhibition relative to the R group was butyl > propyl = t-butyl = octyl = phenyl > ethyl > methyl. This and other aspects of the structure-activity relationship of the monomers and polymers were examined.
Show less - Date Issued
- 2006
- PURL
- http://purl.flvc.org/fcla/dt/13410
- Subject Headings
- Apoptosis--Molecular aspects, Polymeric composites, Organometallic compounds, Cancer--Molecular aspects, Antineoplastic agents--Testing, Polymers in medicine
- Format
- Document (PDF)
- Title
- A New Approach to Sensitized Luminescence in Trivalent Lanthanide Coordination Polymers: From Fundamental Luminescence and Crystal Engineering Toward Sensing Applications.
- Creator
- Einkauf, Jeffrey D., De Lill, Daniel T., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Luminescent lanthanide containing coordination polymers and metal-organic frameworks hold great potential in many applications due to their distinctive spectroscopic properties. While the ability to design coordination polymers for specific functions is often mentioned as a major benefit bestowed upon these compounds, the lack of a meaningful understanding of the crystal engineering and luminescence in lanthanide coordination polymers remains a significant challenge toward functional design....
Show moreLuminescent lanthanide containing coordination polymers and metal-organic frameworks hold great potential in many applications due to their distinctive spectroscopic properties. While the ability to design coordination polymers for specific functions is often mentioned as a major benefit bestowed upon these compounds, the lack of a meaningful understanding of the crystal engineering and luminescence in lanthanide coordination polymers remains a significant challenge toward functional design. Currently, the study of luminescence attributed to these compounds is based on the antenna effect as derived from molecular systems, where organic antennae are used to facilitate lanthanide-centered luminescence. This molecular based approach does not take into account the unique features of extended network solids, particularly the formation of band structure. By comparing molecular and band-based approaches, it was determined that the band structure of the organic sensitizing linker needs to be considered when evaluating the luminescence of lanthanide coordination polymers. This new model, as well as work on the crystal engineering and sensor applications of these materials will be presented.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004890, http://purl.flvc.org/fau/fd/FA00004890
- Subject Headings
- Rare earth metals., Lanthanide shift reagents., Organic compounds--Synthesis., Inorganic compounds--Synthesis., Metallic composites--Speciation., Polymeric composites., Organorare earth metal compounds., Nanostructured materials.
- Format
- Document (PDF)