Search results for " Hydrothermal Aging"

showing 6 items of 6 documents

Water diffusion and swelling stresses in ionizing radiation cured epoxy matrices

2017

Abstract In this work a DGEBF epoxy monomer was cured by electron beam radiation in the presence of an iodonium salt and the obtained system was hydrothermally aged as such and also after a thermal treatment, in order to obtain two systems having different uniformity in the cross-linking degree. On both systems, the transient stress field arising from swelling was measured and monitored by an optical Photoelastic technique and the results were commented with reference to a thermally cured epoxy system containing the same monomer and already discussed in a previous work. Beam samples with identical dimensions, obtained from the irradiated systems, have been aged at 80 °C in water, and charac…

Materials scienceDynamic mechanical thermal analysis Epoxy resins Hydrothermal aging Photoelastic Stress Analysis Radiation curing SwellingPolymers and Plastics02 engineering and technologyThermal treatment010402 general chemistry01 natural sciencesMaterials ChemistrymedicineIrradiationComposite materialCuring (chemistry)EpoxyDynamic mechanical analysis021001 nanoscience & nanotechnologyCondensed Matter Physics0104 chemical sciencesStress fieldMechanics of Materialsvisual_artvisual_art.visual_art_mediumGravimetric analysisSettore CHIM/07 - Fondamenti Chimici Delle TecnologieSwellingmedicine.symptom0210 nano-technology
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Photoelastic stress analysis assisted evaluation of fracture toughness in hydrothermally aged epoxies

2014

The present work has investigated the fracture toughness of a model DGEBA epoxy system subject to Hidro-Thermal aging. A Photoelastic Stress Analysis technique has been implemented, showing the evolution of stresses arising throughout the water uptake process due to the non-uniform swelling of the material. Gravimetric and Dynamic Mechanical Thermal Analyses have further complemented the characterization, showing the onset of plasticization effects with aging. The correlation of all previous characterizations has allowed to conclude that an increase of KIC fracture toughness is obtained at the fully saturated condition. In particular Photoelasticity has also revealed the onset of relevant s…

ToughnessMaterials scienceAbsorption of waterlcsh:Mechanical engineering and machinerylcsh:TA630-695Stress (mechanics)Thermosetting ResinSettore ING-IND/14 - Progettazione Meccanica E Costruzione Di MacchineFracture toughnessFracture Toughnessmedicinelcsh:TJ1-1570Hydrothermal AgingComposite materialPhotoelasticityFracture Toughness; Hydrothermal Aging; Thermosetting Resin; Swelling Stresses; Photoelastic Stress Analysis.Mechanical EngineeringEpoxylcsh:Structural engineering (General)Fracture ToughneSwelling StresseSwelling StressesMechanics of Materialsvisual_artvisual_art.visual_art_mediumPhotoelastic Stress Analysis.Gravimetric analysisSettore CHIM/07 - Fondamenti Chimici Delle TecnologieSwellingmedicine.symptom
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Water diffusion and swelling stresses in highly crosslinked epoxy matrices

2016

Abstract The present work investigates the swelling induced stresses arising in two epoxy systems during water uptake. The analysed systems are two epoxy resin based on DGEBA monomer and DGEBF monomer respectively, both fully cured by DDS amine. The systems achieve different cross-link density degrees, and are characterised by high glass transition temperatures ranging between 200 and 230 °C. Both epoxies have been conditioned in deionized water baths at two different temperatures (50 °C and 80 °C). A desorption process at room temperature in a dry airborne environment was performed after saturation. Dynamic Mechanical Thermal Analysis, carried out at the various stages of hydrothermal cond…

Materials scienceEpoxy Resin; Hydrothermal Aging; Swelling; Dynamic Mechanical Thermal Analysis; Photoelastic Stress AnalysisPolymers and PlasticsDynamic Mechanical Thermal Analysi02 engineering and technology010402 general chemistry01 natural sciencesPhotoelastic Stress AnalysisStress (mechanics)DesorptionMaterials ChemistrymedicineHydrothermal AgingComposite materialThermal analysisSwellingEpoxy021001 nanoscience & nanotechnologyCondensed Matter Physics0104 chemical sciencesMechanics of MaterialsEpoxy Resinvisual_artvisual_art.visual_art_mediumSettore CHIM/07 - Fondamenti Chimici Delle TecnologieSwellingmedicine.symptomAbsorption (chemistry)0210 nano-technologyGlass transitionSaturation (chemistry)
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ELECTROSPUN NANOFIBROUS MATS IN FIBRE REINFORCED EPOXY LAMINATES

ElectrospinningInterlaminar fracture toughneHydrothermal agingNanofiberFiber reinforced epoxy composites; Electrospinning; Nanofiber; Interlaminar fracture toughness; Hydrothermal agingFiber reinforced epoxy composite
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Fracture Toughness of Hydrothermally Aged Epoxy Systems with Different Crosslink Density

2015

Abstract The present work investigates the fracture toughness behaviour of Single Edge Notched Bending (SENB) samples of epoxy systems subject to water uptake aging. Two epoxy systems with a significantly different Glass Transition Temperature, T g , are in particular considered: a typical commercial non-aeronautical grade resin matrix for composite applications, reaching a T g of 90 °C, and a DGEBA+DDS epoxy system achieving a T g of 230 °C.The materials have been conditioned by hydrothermal aging in a thermal bath at the temperature of 50 °C. TransmissionPhotoelastic Stress Analysisis carried outon SENB samples during water aging, monitoring the presence and evolution of swelling stresses…

Materials sciencePhotoelastic Stress AnalysiImage AnalysiComposite numberPhotoelastic Stress AnalysisStress (mechanics)Thermosetting ResinFracture toughnessEngineering (all)Fracture ToughnessHydrothermal AgingFracture Toughness; Hydrothermal Aging; Image Analysis; Photoelastic Stress Analysis; Swelling Stresses; Thermosetting Resin; Engineering (all)Composite materialEngineering(all)Image Analysis.General MedicineEpoxyDynamic mechanical analysisFracture ToughneSwelling StresseSwelling Stressesvisual_artvisual_art.visual_art_mediumFracture (geology)Gravimetric analysisGlass transition
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Mode I fracture toughness behavior of hydro-thermally aged carbon fibre reinforced DGEBA-HHPA-PES systems

2012

In this work the Mode I fracture toughness behavior of unidirectional CFRP laminates is investigated by means of Double Cantilever Beam (DCB) tests. The composite samples were manufactured by thermal curing after impregnation of a Carbon fabric with a DGEBA epoxy and anhydride HHPA curing agent. One resin batch was also mixed with a PES thermoplastic monomer to enhance the matrix toughness. Two lots of samples, toughened and un-toughened, were then left to soak in hot water to achieve various degrees of aging. The influence of matrix toughening and hydrothermal aging on the delamination behavior of the composite have then been assessed and correlated with characterization data from Dynamic …

chemistry.chemical_classificationToughnessMaterials scienceThermoplasticScanning electron microscopeComposite numberEpoxyDynamic mechanical analysisFracture toughnessSettore ING-IND/22 - Scienza E Tecnologia Dei Materialichemistryvisual_artCFRP Delamination Fracture Toughness Epoxy Resins Hydrothermal Agingvisual_art.visual_art_mediumComposite materialCuring (chemistry)
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