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Accelerated ageing and lifetime prediction of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) in distilled water ArchiMer
Deroine, Morgan; Le Duigou, Antoine; Corre, Yves-marie; Le Gac, Pierre-yves; Davies, Peter; Cesar, Guy; Bruzaud, Stephane.
Accelerated ageing was performed in distilled water at different temperatures (25, 30, 40 and 50°C) on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), which is a biodegradable biopolymer, in order to estimate its lifetime in aqueous environment. In a first part, degradation mechanisms were followed by gravimetry, tensile tests and steric exclusion chromatography. Both immersion and relative humidity have been examined. In a second part, the strain at break was used as an indicator for lifetime prediction with an Arrhenius extrapolation. The study revealed the presence of only one irreversible degradation mechanism, i.e. hydrolytic degradation, which is temperature dependant. So, within the approach assumptions, the lifetime in distilled water of PHBV...
Tipo: Text Palavras-chave: Poly(3-hydroxybutyrate-co-3-hydroxyvalerate); Accelerated ageing; Hydrothermal degradation; Lifetime prediction.
Ano: 2014 URL: http://archimer.ifremer.fr/doc/00203/31396/29785.pdf
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Accelerated ageing of polylactide in aqueous environments: Comparative study between distilled water and seawater ArchiMer
Deroine, Morgan; Le Duigou, Antoine; Corre, Yves-marie; Le Gac, Pierre-yves; Davies, Peter; Cesar, Guy; Bruzaud, Stephane.
Pollution of nature by plastics is a major environmental problem and the challenge for the future is to manage the lifetime of polymers better. The aim of this study is to establish a baseline on degradation mechanism and degradation kinetics for lifetime prediction of polylactide (PLA) in a marine environment. The ageing of PLA was accelerated by raising temperature in distilled water, filtered and renewed seawater and natural seawater. Samples were immersed in distilled water for six months at different temperatures (25, 30, 40 and 50°C) in order to evaluate the influence of temperature on PLA degradation kinetics and to predict lifetime. Then, samples were immersed in seawater both in the laboratory and at sea, in order to compare the effects of...
Tipo: Text Palavras-chave: PLA; Accelerated ageing; Hydrothermal ageing; Degradation.
Ano: 2014 URL: http://archimer.ifremer.fr/doc/00173/28376/26689.pdf
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Ageing mechanism and mechanical degradation behaviour of polychloroprene rubber in a marine environment: Comparison of accelerated ageing and long term exposure ArchiMer
Le Gac, Pierre-yves; Le Saux, V.; Paris, M; Marco, Y..
Polymers are widely used in marine environments due to their excellent properties and good weathering resistance. Despite this extensive use, their long term behaviour in such an aggressive environment is still not well known. To assess the polymer durability within reasonable durations, it is essential to perform accelerated ageing tests to accelerate the degradation kinetics but without any modification of the degradation process. This study therefore proposes and validates accelerated ageing tests to study marine ageing of a silica-filled chloroprene rubber (CR) used for offshore applications. Several accelerated ageing protocols are investigated for temperatures ranging from 20 to 80 degrees C in renewed natural seawater. The ageing consequences are...
Tipo: Text Palavras-chave: Chloroprene rubber; Degradation; Sea water; Silica; Accelerated ageing; Natural ageing.
Ano: 2012 URL: http://archimer.ifremer.fr/doc/00073/18429/20232.pdf
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Analysis of the moisture effect on the mechanical behaviour of an adhesively bonded joint under proportional multi-axial loads ArchiMer
Arnaud, N.; Creac'Hcadec, R.; Cognard, J. Y.; Davies, Peter; Le Gac, Pierre-yves.
The objective of the study is to identify the 3D behaviour of an adhesive in an assembly, and to take into account the effect of ageing in a marine environment. To that end, three different tests were employed. Gravimetric analyses were used to determine the water diffusion kinetics in the adhesive. Bulk tensile tests were performed to highlight the effects of humid ageing on the adhesive behaviour. Modified Arcan tests were performed for several ageing times to obtain the experimental database which was necessary to identify constitutive models. A Mahnken-Schlimmer type model was determined for the unaged state according to a procedure developed in a previous study. This identification used inverse techniques. It was based on the unaged modified Arcan...
Tipo: Text Palavras-chave: Water resistance; Arcan test; Ageing; Epoxides; Finite-element stress analysis; Durability.
Ano: 2015 URL: http://archimer.ifremer.fr/doc/00277/38788/37557.pdf
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Assessing the performance durability of elastomeric moorings: Assembly investigations enhanced by sub-component tests ArchiMer
Gordelier, T.; Parish, D.; Thies, P. R.; Weller, S.; Davies, Peter; Le Gac, Pierre-yves; Johanning, L..
The growing marine renewable energy sector has led to a demand for increasingly compliant mooring systems. In response, several innovative mooring tethers have been proposed demonstrating potential customisation to the stiffness profile and reduced peak mooring loads. Many of these novel systems utilise materials in a unique application within the challenging marine environment and their long term durability remains to be proven. This paper presents a multifaceted investigation into the durability of a novel polyester mooring tether with an elastomeric core. Laboratory based functionality tests are repeated on tether assemblies following a 6 month sea deployment. Results show a 45% average increase in dynamic axial stiffness. This is supported by high...
Tipo: Text Palavras-chave: Marine energy; Mooring; Elastomer; Durability; EPDM; Component testing.
Ano: 2018 URL: http://archimer.ifremer.fr/doc/00434/54605/55987.pdf
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Degradation of rubber to metals bonds during its cathodic delamination, validation of an artificial ageing test ArchiMer
Nakache, Maryline; Aragon, Emmanuel; Belec, Lenaik; Perrin, Francois-xavier; Roux, Gerard; Le Gac, Pierre-yves.
Rubber-metal assemblies used for submarine applications are often associated to cathodic protection which can lead to cathodic disboncling of the polymer/metal interface. The degradation mechanisms of polychloroprene/epoxy adhesive/copper-aluminium substrate systems associated to an accelerated ageing test are compared to the degradations resulting from natural ageing conditions in the Mediterranean sea. From destructives tests, a kinetic in four steps is identified for both ageing conditions. This kinetic is confirmed by Electrochemical Impedance Spectroscopy data during ageing. In order to further identify the failure mode, the disbondecl surfaces on polymer and steel sides are analyzed using SEM and FTIR. Both ageing conditions present the same type of...
Tipo: Text Palavras-chave: Ageing; Rubber to metal systems; Cathodic delamination; FTIR.
Ano: 2011 URL: http://archimer.ifremer.fr/doc/00056/16697/14370.pdf
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Description and modeling of polyurethane hydrolysis used as thermal insulation in oil offshore conditions ArchiMer
Le Gac, Pierre-yves; Choqueuse, Dominique; Melot, D..
Polymers are widely used for passive thermal insulation coatings on steel pipe in offshore oil and gas production. In this industry, structures used in deep sea have to be reliable, as they are in service for more than 20 years in a very severe environment: sea water, hydrostatic pressure and temperature gradient. One of the main questions is how to test and predict the lifetime of such structures in the laboratory? This study presents one approach that has been developed to characterize and predict the degradation of polymers used as thermal insulation materials. This paper is dedicated to polyurethane (polyether based) degradation in sea water at high temperature. Ageing has been performed in natural sea water under hydrostatic pressure at temperatures...
Tipo: Text Palavras-chave: Polyurethane; Hydrolysis; Accelerated ageing; Sea water; Coating; Offshore.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00160/27132/25330.pdf
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Durability of polydicyclopentadiene under high temperature, high pressure and seawater (offshore oil production conditions) ArchiMer
Le Gac, Pierre-yves; Choqueuse, Dominique; Paris, Marc; Recher, G.; Zimmer, Celine; Melot, D..
In the offshore industry polymer coatings are widely used to ensure thermal insulation of steel pipes, and to avoid over-cooling of the hot oil inside. Because of very severe service conditions (i.e. high temperature, high pressure and presence of seawater) and an expected life time of 20 years, durability of these coatings is a major issue for this industry. Polypropylene and polyurethane are often used for this application, nevertheless these polymers have some limitations in terms of processing time for polypropylene and maximum service temperature for polyurethane. Polycyclopentadiene (pDCPD) shows good processing characteristics and low thermal conductivity, so this polymer could be a good alternative coating in the offshore industry, but the...
Tipo: Text Palavras-chave: Polydicyclopentadiene; Seawater; Accelerated ageing; Oxidation; Offshore; Field joint.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00114/22534/20233.pdf
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Effect of sea water and humidity on the tensile and compressive properties of carbon-polyamide 6 laminates ArchiMer
Arhant, Mael; Le Gac, Pierre-yves; Le Gall, Maelenn; Burtin, Christian; Briancon, Christophe; Davies, Peter.
Thermoplastic matrix carbon fibre composites offer considerable potential for underwater applications. Various material options exist but there are questions concerning the tension/compressive behaviour and water sensitivity of the less expensive polymers (e.g. polyamides) for these applications. The aim of the current work is to model water diffusion and its effect on the mechanical properties of thick carbon fibre reinforced polyamide-6 composite cylinders immersed in sea water for deep sea applications. To provide the data for such a model, thin specimens (2 mm thick) have been aged under different humidity conditions and tested in tension and compression. As water enters the composite, a significant reduction in the laminate properties is observed. An...
Tipo: Text Palavras-chave: Thermoplastic; Carbon fibres; Environmental degradation; Mechanical testing.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00368/47937/47971.pdf
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Evaluation of Long Term Behaviour of Polymers for Offshore Oil and Gas Applications ArchiMer
Le Gac, Pierre-yves; Davies, Peter; Choqueuse, Dominique.
Polymers and composites are very attractive for underwater applications, but it is essential to evaluate their long term behaviour in sea water if structural integrity of offshore structures is to be guaranteed. Accelerated test procedures are frequently required, and this paper will present three examples showing how the durability of polymers, in the form of fibres, matrix resins in fibre reinforced composites for structural elements, and thermal insulation coatings of flow-lines, have been evaluated for offshore use. The influence of the ageing medium, temperature, and hydrostatic pressure will be discussed first, then an example of the application of ageing test results to predict long term behavior of the thermal insulation coating of a flowline will...
Tipo: Text
Ano: 2014 URL: http://archimer.ifremer.fr/doc/00199/30978/29356.pdf
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Fatigue behavior of natural rubber in marine environment: Comparison between air and sea water ArchiMer
Le Gac, Pierre-yves; Arhant, Mael; Davies, Peter; Muhr, Alan.
Natural rubber has been successfully used in a marine environment for many years. However, most applications involve low dynamic loadings. Due to the emergence of marine energy recovery, wave and tidal energy converters are being developed. In some such devices, rubbers are subjected to severe cyclic loadings, very different from their previous use in air or water. Such rubbers must therefore be qualified for long-term use in sea water with high fatigue loading. This paper presents a study using a new fatigue machine that allows the fatigue behaviour of rubber in sea water to be compared to that in air. The results show that the benefit of non-relaxing conditions on fatigue lifetime of natural rubber can be significantly reduced when it is used in sea...
Tipo: Text Palavras-chave: Natural Rubber; Water; Fatigue; Stabilisation.
Ano: 2015 URL: http://archimer.ifremer.fr/doc/00211/32240/32195.pdf
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Fatigue resistance of natural rubber in seawater with comparison to air ArchiMer
Ulu, K. Narynbek; Huneau, B.; Le Gac, Pierre-yves; Verron, E..
Fatigue properties of filled natural rubber in seawater environment are investigated by uniaxial fatigue and crack propagation experiments, and the damage is analyzed by scanning electron microscopy. The behavior under relaxing and non-relaxing loading conditions is studied and the results are compared to those obtained in air environment. For relaxing loading conditions, fatigue behavior is the same in both environments. Under non-relaxing conditions at large strain levels, for which the influence of strain-induced crystallization is important, fatigue life is longer in seawater. Such behavior could be explained by increased internal temperatures of specimens tested in air due to lower heat conductivity of air as compared to seawater. Such conclusion is...
Tipo: Text Palavras-chave: Natural rubber; Fatigue; Environmental effects; Seawater; Strain-induced crystallization.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00324/43523/43055.pdf
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Influence of Sea Water Aging on the Mechanical Behaviour of Acrylic Matrix Composites ArchiMer
Davies, Peter; Le Gac, Pierre-yves; Le Gall, Maelenn.
A new matrix resin was recently introduced for composite materials, based on acrylic resin chemistry allowing standard room temperature infusion techniques to be used to produce recyclable thermoplastic composites. This is a significant advance, particularly for more environmentally-friendly production of large marine structures such as boats. However, for such applications it is essential to demonstrate that composites produced with these resins resist sea water exposure in service. This paper presents results from a wet aging study of unreinforced acrylic and glass and carbon fibre reinforced acrylic composites. It is shown that the acrylic matrix resin is very stable in seawater, showing lower property losses after seawater aging than those of a...
Tipo: Text Palavras-chave: Acrylic; Thermoplastic; Infusion; Seawater; Immersion.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00347/45815/45541.pdf
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Kinetic analysis of polydicyclopentadiene oxidation ArchiMer
Defauchy, Virginie; Le Gac, Pierre-yves; Guinault, Alain; Verdu, Jacques; Recher, Gilles; Drozdzak, Renata; Richaud, Emmanuel.
The in situ thermal oxidation of thin unstabilized polydicyclopentadiene was studied by TGA to monitor mass gain, and DSC to characterize hydroperoxides concentration. Results were discussed using kinetic analysis, which allowed the estimation of activation energies for key reactions of the oxidation process. Activation energy for termination was shown to be higher than in hydrocarbon liquids, which was discussed from the theory of diffusion controlled reactions, and a possible link with local motions associated with sub-glassy transition. Activation energy of thermal decomposition of hydroperoxides was found lower than for model hydroperoxides, suggesting an accelerating effect of organometallic catalysts. Despite those two results that indicate a poor...
Tipo: Text Palavras-chave: Polydicyclopentadiene; Thermal oxidation; Segmental mobility; Catalysis; Diffusion limited oxidation.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00388/49904/50476.pdf
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Life time prediction of polymer used as thermal insulation in offshore oil production conditions: Ageing on real structure and reliability of prediction ArchiMer
Le Gac, Pierre-yves; Choqueuse, Dominique; Melot, D.; Melve, B.; Meniconi, L..
Polymers are widely used for passive thermal insulation coatings on steel pipe in offshore oil and gas production. In this industry, structures used in deep sea have to be reliable as they are in service for more than 20 years in a very severe environment: sea water, hydrostatic pressure, temperature. One of the main questions is how to test and predict the lifetime of such structures in the laboratory. This study presents one approach that has been developed to characterize and predict the degradation of polyurethanes used as thermal insulation materials. Based on results obtained during accelerated ageing of the PU in sea water, a prediction of degradation through the thickness has been set up taking into account the temperature profile in the coating,...
Tipo: Text Palavras-chave: Polyurethane; Life time prediction; Hydrolysis; Offshore; Thermal insulation; Durability.
Ano: 2014 URL: http://archimer.ifremer.fr/doc/00174/28572/26957.pdf
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Limits in the validity of Arrhenius predictions for field ageing of a silica filled polychloroprene in a marine environment ArchiMer
Le Saux, V.; Le Gac, Pierre-yves; Marco, Y.; Calloch, S..
Accelerated ageing in natural sea water at different temperatures from 20°C to 80°C was performed on a silica filled polychloroprene rubber. Degradation when monitored with mechanical properties at both macroscopic and microscopic scale led to a large increase of the modulus coupled with a strong decrease of strain and stress at break. Data from tensile tests were used for lifetime prediction with an Arrhenius extrapolation for modulus, strain and stress at break. The validity of this lifetime prediction was evaluated using a 23 year-old sample aged in natural conditions. Strain at break could be predicted using an Arrhenius extrapolation with an activation energy of 50 kJ/mol. However, an extrapolation based on linear Arrhenius behavior did not apply for...
Tipo: Text Palavras-chave: Polychloroprene rubber; Accelerated and natural ageing tests; Arrhenius extrapolation; Lifetime prediction; Sea water.
Ano: 2014 URL: http://archimer.ifremer.fr/doc/00164/27523/25679.pdf
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Long-term durability of CFRP under fatigue loading for marine applications ArchiMer
Le Guen-geffroy, Antoine; Le Gac, Pierre-yves; Diakhate, Malick; Habert, Bertrand; Davies, Peter.
Composite propellers are a major new development in the marine transport industry. The use of composite materials in seawater turbines is also of great interest to the marine renewable energy industry. Those systems present similarities being both constantly immersed in seawater, under fatigue loadings, of large dimensions, and they are often designed using Carbon Fibre Reinforced Polymer (CFRP). Previous studies have shown sensitivity of some composite materials to the seawater environment mainly in the quasi-static loading domain. However, investigations now need to be performed on the behaviour of CFRP under seawater environment and fatigue loadings. In this study, CFRP samples were aged in natural seawater until saturation, in order to investigate the...
Tipo: Text
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00441/55262/56756.pdf
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Modelling the non Fickian water absorption in polyamide 6 ArchiMer
Arhant, Mael; Le Gac, Pierre-yves; Le Gall, Maelenn; Burtin, Christian; Briancon, Christophe; Davies, Peter.
This paper investigates the water absorption of polyamide 6. The high amount of absorbed water in the polymer and the large resulting decrease in the glass transition temperature (Tg) leads to a non Fickian water diffusion when samples are immersed, which is a significant difficulty when trying to model the water profile in thick specimens. The aim of this study is to be able to model this particular behaviour based on physical considerations. First, it is shown that the non Fickian water diffusion is caused by an increase in the diffusivity during water absorption. Two cases are then identified; one below Tg where the diffusivity is described using an Arrhenius law and one above Tg based on the free volume theory. Then, these two laws are implemented in a...
Tipo: Text Palavras-chave: Water absorption; Free volume; Polyamide 6; Sea water; Modelling.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00350/46158/45856.pdf
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Moisture sorption in polyamide 6.6: experimental investigation and comparison to four physical-based models ArchiMer
Broudin, Morgane; Le Saux, V.; Le Gac, Pierre-yves; Champy, C.; Robert, G.; Charrier, P.; Marco, Y..
Water sorption in polyamide 6.6 has been characterized for a wide range of temperature (25°C to 80°C) and various water activities using a Dynamic Vapor Sorption testing machine. Complex sorption mechanisms govern the water uptake in the material. The competition between two main temperature dependant mechanisms has been observed: a Henry’s sorption mechanism that mainly governs the sorption curve at low water activities, and a second mechanism at high water activities that could be related to the formation of water clusters. It is observed that the temperature dependency can mainly be attributed to the Henry’s contribution. Four physically based models are then used and identified thanks to the extended experimental database. It is shown that a simple...
Tipo: Text Palavras-chave: Polyamide 6.6; Water sorption; Temperature; Relative humidity; Physically-based models.
Ano: 2015 URL: https://archimer.ifremer.fr/doc/00252/36371/34911.pdf
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Novel mechanical characterization method for deep sea buoyancy material under hydrostatic pressure ArchiMer
Le Gall, Maelenn; Choqueuse, Dominique; Le Gac, Pierre-yves; Davies, Peter; Perreux, Dominique.
Syntactic foams, used in submersibles and in pipelines for deep sea oil wells, must be resistant to the severe conditions of the deep sea environment. As these foams will be in service for at least 20 years, their qualification testing is crucial. However, their mechanical characterization under real conditions of use is a challenge. In deep sea, the main loading is hydrostatic compression, however there is no standard procedure for testing material under pure hydrostatic pressure. The aim of this paper is to present a new characterization technique based on buoyancy loss measurement under hydrostatic pressure. To validate the method, two different syntactic foams (one brittle and one ductile) have been tested. Their behaviours under hydrostatic pressure...
Tipo: Text Palavras-chave: Hydrostatic compression; Syntactic foam; Deep sea; Mechanical characterization.
Ano: 2014 URL: http://archimer.ifremer.fr/doc/00201/31191/29590.pdf
Registros recuperados: 30
Primeira ... 12 ... Última
 

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