Water diffusivity in PA66: Experimental characterization and modeling based on free volume theory

Broudin, Morgane; Gac, Pierre‐Yves Le; Saux, V. Le; Champy, C.; Gurny, Robert; Charrier, Pierre; Marco, Yann

doi:10.1016/j.eurpolymj.2015.04.015

Cited by 50 publications

(34 citation statements)

References 38 publications

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“…8. The diffusion coefficients are of same order of magnitude than those published in the literature for PA66 at high water activities and at room temperature [41]. As expected, PA6 water uptake at saturation is the highest one (7.6 %) and the diffusion rate of water molecules, faster than in the other samples.…”

Section: Effect Of Mwcnt Contents On Water Uptakesupporting

confidence: 64%

Water sorption of PA12/PA6/MWCNT composites with a segregated conductive network: structure–property relationships

et al. 2016

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The structure-properties relationships of a polyamide 12 (PA12)/polyamide 6 (PA6) blend containing multiwalled carbon nanotubes have been investigated as a function of nanofiller amount. The influence of the filler content in the water diffusion behavior of the immiscible PA12/PA6 blend is studied. An acceptable dispersion level of nanotubes in polymer matrix is observed by scanning electron microscopy. The water uptake at saturation, normalized to the polyamide mass, decreases, and the diffusion rate is slower in CNT composites. The enhancement is in line with the increase in stiffness measured in rheological tests. This behavior is related with the rise in the overall crystallinity of the polymer matrix and the selective migration of CNT towards PA6 (more hygroscopic than PA12). These findings display a substantial improvement in respect to the water uptake behavior of pristine PA6 and PA6/CNT composites, expanding the potential applications of composites.

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Section: Effect Of Mwcnt Contents On Water Uptakesupporting

confidence: 64%

Water sorption of PA12/PA6/MWCNT composites with a segregated conductive network: structure–property relationships

et al. 2016

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“…One can lead to an increase in the chain mobility as water enters the polymer. This phenomenon, plasticising, is known to be reversible and decreases the glass transition temperature [34]. Others are irreversible and involve chain scission such as hydrolysis and oxidation [45], but these are not the purpose of the subject of the current paper.…”

Section: Effect Of Water Ingress On the Glass Transition Temperature mentioning

confidence: 98%

“…The plasticisation due to water absorption can reduce the glass transition temperature of the polymer [32], [33], and swelling may introduce internal stresses. Polyamides are known to be particularly sensitive to water [34]. Water can also cause a degradation of the fibre/matrix interface [35], [36].…”

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confidence: 99%

Effect of sea water and humidity on the tensile and compressive properties of carbon-polyamide 6 laminates

Arhant

Gac

Gall

et al. 2016

Composites Part A: Applied Science and Manufacturing

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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 empirical relationship that links matrix-dominated properties to water content is presented and can be used for modelling purposes.More than 70% of the oceans remain unexplored. With an average depth of over 3800 meters, it is necessary to design exploration devices that are able to withstand high hydrostatic pressures. The lighter these pressure vessels are the more equipment and measuring instruments they can carry, so composites have been used underwater for many years [1]. The use of composites for pressure hulls of underwater vehicles and submarines has been an ongoing research topic for many years, since the early work in the UK by Smith and colleagues in the 1970"s [2]. The use of glass and carbon reinforced thermoset composite materials for deep-sea applications needs a thorough understanding of the behaviour of these materials under hydrostatic pressure.However, the ability to predict the implosion pressures of such materials and under such loadings (bi-axial compression) is not an easy task, as was demonstrated by the results of the World Wide Failure Exercise [3].Applications for thick thermoplastic cylinders for underwater applications are rarer, even though there is an increasing number of thermoplastic matrix polymers available on the market such as polypropylene (PP), polyamide (PA), polyphenylene sulphide (PPS), polyetheretherketone (PEEK), etc. They offer possibilities for forming by local heating, attractive mechanical properties, good environmental resistance and the potential for end of life recycling. More ductile and reparable by melting, they offer a real potential for greatly improved devices. Studies have been conducted in the USA on carbon/PEEK cylinders [4], [5] and by the author [6] and were found to be very promising as they imploded at comparable pressures to those of their carbon/epoxy counterparts. However, it is not clear to what extent the compressive behaviour of thermoplastic composites in the presence of water will limit the operating depth of an underwater pressure vessel, especially for carbon/polyamide 6 (C/PA6) composites. The latter are attractive as they are much less expensive than composites based on high performance matrix polymers such as PEEK.The mechanical behaviour of composite materials has been extensively expl...

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“…During processing and in many applications, polymer products, such as polyethylene, can come in contact with different solvents that can change their morphology and, thus, the macroscopic properties. Morphological changes are generally analyzed by measuring, for example, the reduction in the glass transition temperature ( T g ) due to the plasticization of the amorphous phase or by quantifying changes in the crystalline phase . Yet for semi‐crystalline polymers, the solvents generally penetrate only the amorphous phase and they can induce solvent‐induced crystallization.…”

Section: Resultsmentioning

confidence: 99%

Impact of Exposure Conditions on the Morphology of Polyethylene by Compact NMR

Teymouri

Adams

Blümich

2018

Macromolecular Symposia

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Today many polyethylene (PE) products are employed in long‐term applications that require the use of elevated temperatures and/or contact with different solvents. Both the exposure to heat and solvents can result in morphological changes, compromising the mechanical stability of the material. Disentangling morphological changes induced by either type of exposure and understanding their combined effect is crucial for establishing reliable structure‐property relationships. This, in turn, requires sensitive analytical methods that can probe the complex morphology of PE both in the laboratory and on site. Among existing analytical methods, NMR with compact devices have recently become a key analytical tool for the detailed morphological characterization of a variety of solid polymers including PE. This current work reviews the potential of compact NMR for monitoring and quantifying morphological changes in PE exposed to the aforementioned external conditions. To prove the reliability of compact proton NMR relaxation measurements, the results are compared with data from conventional high‐field proton wide‐line NMR spectroscopy, DSC, and FTIR spectroscopy. It could be shown that simple, static proton relaxation measurements garner detailed information about the exposure‐induced morphological changes through the quantification of phase composition and chain dynamics. Moreover, the NMR method has a key advantage over other methods, because the chain mobility of the soft amorphous phase is a very sensitive microscopic parameter under exposure conditions. The various presented examples and the good agreement of the NMR results with those of other analytical methods show that low‐field NMR is a promising option for in‐situ aging studies.

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Water diffusivity in PA66: Experimental characterization and modeling based on free volume theory

Cited by 50 publications

References 38 publications

Water sorption of PA12/PA6/MWCNT composites with a segregated conductive network: structure–property relationships

Water sorption of PA12/PA6/MWCNT composites with a segregated conductive network: structure–property relationships

Effect of sea water and humidity on the tensile and compressive properties of carbon-polyamide 6 laminates

Impact of Exposure Conditions on the Morphology of Polyethylene by Compact NMR

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