The Experts below are selected from a list of 67926 Experts worldwide ranked by ideXlab platform
Michael R. Kessler - One of the best experts on this subject based on the ideXlab platform.
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Dynamic Mechanical Analysis of fumed silica/cyanate ester nanocomposites
Composites Part A-applied Science and Manufacturing, 2008Co-Authors: W.k. Goertzen, Michael R. KesslerAbstract:Fumed silica particles with average primary particle diameters of 12 and 40 nm were combined with a low viscosity bisphenol E cyanate ester resin to form composite materials with enhanced storage modulus and reduced damping behavior, as evidenced by Dynamic Mechanical Analysis (DMA). The storage modulus increased with volume fraction of fumed silica in both the glassy and rubbery regions, but the increase was more pronounced in the rubbery region. The maximum increase in storage modulus in the glassy region was 75% for 20.7 vol% of 40 nm fumed silica, while the same composition showed a 231% increase in the rubbery storage modulus. Furthermore, decreases in damping behavior were used to estimate the effective polymer-particle interphase thickness. The glass transition temperature of the nanocomposites was not changed significantly with increasing volume fraction.
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Dynamic Mechanical Analysis of fumed silica cyanate ester nanocomposites
Composites Part A-applied Science and Manufacturing, 2008Co-Authors: W.k. Goertzen, Michael R. KesslerAbstract:Fumed silica particles with average primary particle diameters of 12 and 40 nm were combined with a low viscosity bisphenol E cyanate ester resin to form composite materials with enhanced storage modulus and reduced damping behavior, as evidenced by Dynamic Mechanical Analysis (DMA). The storage modulus increased with volume fraction of fumed silica in both the glassy and rubbery regions, but the increase was more pronounced in the rubbery region. The maximum increase in storage modulus in the glassy region was 75% for 20.7 vol% of 40 nm fumed silica, while the same composition showed a 231% increase in the rubbery storage modulus. Furthermore, decreases in damping behavior were used to estimate the effective polymer-particle interphase thickness. The glass transition temperature of the nanocomposites was not changed significantly with increasing volume fraction.
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Dynamic Mechanical Analysis of carbon/epoxy composites for structural pipeline repair
Composites Part B: Engineering, 2007Co-Authors: W.k. Goertzen, Michael R. KesslerAbstract:Abstract The viscoelastic behavior of a carbon fiber/epoxy matrix composite material system used for pipeline repair has been evaluated though Dynamic Mechanical Analysis. The effects of the heating rate, frequency, and measurement method on the glass transition temperature ( T g ) were studied. The increase in T g with frequency was related to the activation energy of the glass transition relaxation. The activation energy can be used for prediction of long term performance. The measured tan delta peak T g ’s of room temperature cured and post-cured composite specimens ranged from 60 to 129 °C. Analysis of T g data at various cure states was used to determine use temperature limits for the composite repair system.
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Dynamic Mechanical Analysis of carbon epoxy composites for structural pipeline repair
Composites Part B-engineering, 2007Co-Authors: W.k. Goertzen, Michael R. KesslerAbstract:Abstract The viscoelastic behavior of a carbon fiber/epoxy matrix composite material system used for pipeline repair has been evaluated though Dynamic Mechanical Analysis. The effects of the heating rate, frequency, and measurement method on the glass transition temperature ( T g ) were studied. The increase in T g with frequency was related to the activation energy of the glass transition relaxation. The activation energy can be used for prediction of long term performance. The measured tan delta peak T g ’s of room temperature cured and post-cured composite specimens ranged from 60 to 129 °C. Analysis of T g data at various cure states was used to determine use temperature limits for the composite repair system.
W.k. Goertzen - One of the best experts on this subject based on the ideXlab platform.
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Dynamic Mechanical Analysis of fumed silica/cyanate ester nanocomposites
Composites Part A-applied Science and Manufacturing, 2008Co-Authors: W.k. Goertzen, Michael R. KesslerAbstract:Fumed silica particles with average primary particle diameters of 12 and 40 nm were combined with a low viscosity bisphenol E cyanate ester resin to form composite materials with enhanced storage modulus and reduced damping behavior, as evidenced by Dynamic Mechanical Analysis (DMA). The storage modulus increased with volume fraction of fumed silica in both the glassy and rubbery regions, but the increase was more pronounced in the rubbery region. The maximum increase in storage modulus in the glassy region was 75% for 20.7 vol% of 40 nm fumed silica, while the same composition showed a 231% increase in the rubbery storage modulus. Furthermore, decreases in damping behavior were used to estimate the effective polymer-particle interphase thickness. The glass transition temperature of the nanocomposites was not changed significantly with increasing volume fraction.
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Dynamic Mechanical Analysis of fumed silica cyanate ester nanocomposites
Composites Part A-applied Science and Manufacturing, 2008Co-Authors: W.k. Goertzen, Michael R. KesslerAbstract:Fumed silica particles with average primary particle diameters of 12 and 40 nm were combined with a low viscosity bisphenol E cyanate ester resin to form composite materials with enhanced storage modulus and reduced damping behavior, as evidenced by Dynamic Mechanical Analysis (DMA). The storage modulus increased with volume fraction of fumed silica in both the glassy and rubbery regions, but the increase was more pronounced in the rubbery region. The maximum increase in storage modulus in the glassy region was 75% for 20.7 vol% of 40 nm fumed silica, while the same composition showed a 231% increase in the rubbery storage modulus. Furthermore, decreases in damping behavior were used to estimate the effective polymer-particle interphase thickness. The glass transition temperature of the nanocomposites was not changed significantly with increasing volume fraction.
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Dynamic Mechanical Analysis of carbon/epoxy composites for structural pipeline repair
Composites Part B: Engineering, 2007Co-Authors: W.k. Goertzen, Michael R. KesslerAbstract:Abstract The viscoelastic behavior of a carbon fiber/epoxy matrix composite material system used for pipeline repair has been evaluated though Dynamic Mechanical Analysis. The effects of the heating rate, frequency, and measurement method on the glass transition temperature ( T g ) were studied. The increase in T g with frequency was related to the activation energy of the glass transition relaxation. The activation energy can be used for prediction of long term performance. The measured tan delta peak T g ’s of room temperature cured and post-cured composite specimens ranged from 60 to 129 °C. Analysis of T g data at various cure states was used to determine use temperature limits for the composite repair system.
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Dynamic Mechanical Analysis of carbon epoxy composites for structural pipeline repair
Composites Part B-engineering, 2007Co-Authors: W.k. Goertzen, Michael R. KesslerAbstract:Abstract The viscoelastic behavior of a carbon fiber/epoxy matrix composite material system used for pipeline repair has been evaluated though Dynamic Mechanical Analysis. The effects of the heating rate, frequency, and measurement method on the glass transition temperature ( T g ) were studied. The increase in T g with frequency was related to the activation energy of the glass transition relaxation. The activation energy can be used for prediction of long term performance. The measured tan delta peak T g ’s of room temperature cured and post-cured composite specimens ranged from 60 to 129 °C. Analysis of T g data at various cure states was used to determine use temperature limits for the composite repair system.
Kyriakos Komvopoulos - One of the best experts on this subject based on the ideXlab platform.
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Viscoelastic properties of plasma-treated low-density polyethylene surfaces determined by nanoscale Dynamic Mechanical Analysis
Materials Research Letters, 2019Co-Authors: Ayyana M. Chakravartula, Lisa A. Pruitt, Kyriakos KomvopoulosAbstract:Nanoscale Dynamic Mechanical Analysis (nanoDMA) was used to determine changes in surface viscoelastic properties of low-density polyethylene (LDPE) due to Ar plasma treatment. The experimental resu...
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Viscoelastic properties of polymer surfaces investigated by nanoscale Dynamic Mechanical Analysis
Applied Physics Letters, 2006Co-Authors: Ayyana M. Chakravartula, Kyriakos KomvopoulosAbstract:The viscoelastic properties of polymer surfaces were investigated by nanoscale Dynamic Mechanical Analysis (nano-DMA) involving contact force modulation in the frequency range of 10–200Hz. Nano-DMA experiments were performed with a Berkovich diamond tip of nominal radius of curvature equal to ∼100nm under a mean contact force of 8–10μN and alternating force equal to 2% of the mean force. Variations in the loss tangent, storage modulus, and loss modulus of low- and high-density polyethylene and ultrahigh molecular weight polyethylene with the force frequency demonstrated significantly different viscoelastic behaviors for shallow depths (
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viscoelastic properties of polymer surfaces investigated by nanoscale Dynamic Mechanical Analysis
Applied Physics Letters, 2006Co-Authors: Ayyana M. Chakravartula, Kyriakos KomvopoulosAbstract:The viscoelastic properties of polymer surfaces were investigated by nanoscale Dynamic Mechanical Analysis (nano-DMA) involving contact force modulation in the frequency range of 10–200Hz. Nano-DMA experiments were performed with a Berkovich diamond tip of nominal radius of curvature equal to ∼100nm under a mean contact force of 8–10μN and alternating force equal to 2% of the mean force. Variations in the loss tangent, storage modulus, and loss modulus of low- and high-density polyethylene and ultrahigh molecular weight polyethylene with the force frequency demonstrated significantly different viscoelastic behaviors for shallow depths (<40nm) than for relatively large depths (i.e., 75–100nm). The effects of alternating force frequency and indentation depth on the viscoelastic properties of the different polyethylene materials are interpreted in terms of the microstructure characteristics and the molecular chain mobility at the polymer surfaces. The results show that nano-DMA is an effective technique for ...
Eli Ruckenstein - One of the best experts on this subject based on the ideXlab platform.
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thermal and Dynamic Mechanical Analysis of pva mc blend hydrogels
Polymer, 2001Co-Authors: J.-s Park, J.-w Park, Eli RuckensteinAbstract:New blend hydrogels based on poly(vinyl alcohol) (PVA) and methylcellulose (MC) were prepared by crosslinking in an aqueous solution with glutaraldehyde (GA) in the presence of HCl. The state of the miscibility of the blend hydrogel films was examined over the entire composition range by differential scanning calorimetry (DSC) and Dynamic Mechanical Analysis (DMA). Depressions of the melting and crystallization temperatures of PVA were observed with increasing MC content and crosslinking density via the DSC. The determination of the glass transition temperature of blend hydrogels by DMA indicated that they exhibit a higher miscibility than the non-crosslinked blends.
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Thermal and Dynamic Mechanical Analysis of PVA/MC blend hydrogels
Polymer, 2001Co-Authors: J.-s Park, J.-w Park, Eli RuckensteinAbstract:New blend hydrogels based on poly(vinyl alcohol) (PVA) and methylcellulose (MC) were prepared by crosslinking in an aqueous solution with glutaraldehyde (GA) in the presence of HCl. The state of the miscibility of the blend hydrogel films was examined over the entire composition range by differential scanning calorimetry (DSC) and Dynamic Mechanical Analysis (DMA). Depressions of the melting and crystallization temperatures of PVA were observed with increasing MC content and crosslinking density via the DSC. The determination of the glass transition temperature of blend hydrogels by DMA indicated that they exhibit a higher miscibility than the non-crosslinked blends.
Ayyana M. Chakravartula - One of the best experts on this subject based on the ideXlab platform.
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Viscoelastic properties of plasma-treated low-density polyethylene surfaces determined by nanoscale Dynamic Mechanical Analysis
Materials Research Letters, 2019Co-Authors: Ayyana M. Chakravartula, Lisa A. Pruitt, Kyriakos KomvopoulosAbstract:Nanoscale Dynamic Mechanical Analysis (nanoDMA) was used to determine changes in surface viscoelastic properties of low-density polyethylene (LDPE) due to Ar plasma treatment. The experimental resu...
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Viscoelastic properties of polymer surfaces investigated by nanoscale Dynamic Mechanical Analysis
Applied Physics Letters, 2006Co-Authors: Ayyana M. Chakravartula, Kyriakos KomvopoulosAbstract:The viscoelastic properties of polymer surfaces were investigated by nanoscale Dynamic Mechanical Analysis (nano-DMA) involving contact force modulation in the frequency range of 10–200Hz. Nano-DMA experiments were performed with a Berkovich diamond tip of nominal radius of curvature equal to ∼100nm under a mean contact force of 8–10μN and alternating force equal to 2% of the mean force. Variations in the loss tangent, storage modulus, and loss modulus of low- and high-density polyethylene and ultrahigh molecular weight polyethylene with the force frequency demonstrated significantly different viscoelastic behaviors for shallow depths (
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viscoelastic properties of polymer surfaces investigated by nanoscale Dynamic Mechanical Analysis
Applied Physics Letters, 2006Co-Authors: Ayyana M. Chakravartula, Kyriakos KomvopoulosAbstract:The viscoelastic properties of polymer surfaces were investigated by nanoscale Dynamic Mechanical Analysis (nano-DMA) involving contact force modulation in the frequency range of 10–200Hz. Nano-DMA experiments were performed with a Berkovich diamond tip of nominal radius of curvature equal to ∼100nm under a mean contact force of 8–10μN and alternating force equal to 2% of the mean force. Variations in the loss tangent, storage modulus, and loss modulus of low- and high-density polyethylene and ultrahigh molecular weight polyethylene with the force frequency demonstrated significantly different viscoelastic behaviors for shallow depths (<40nm) than for relatively large depths (i.e., 75–100nm). The effects of alternating force frequency and indentation depth on the viscoelastic properties of the different polyethylene materials are interpreted in terms of the microstructure characteristics and the molecular chain mobility at the polymer surfaces. The results show that nano-DMA is an effective technique for ...
