Nuclear Magnetic Resonance Imaging Characterization of Resistance Properties of Polymers to Solvent Diffusion

Maddinelli, G.; Iwanski, Philippe; Callaioli, A.; Ravanetti, Gian Paolo

doi:10.1080/10236660600640557

Cited by 4 publications

(3 citation statements)

References 7 publications

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“…In this case, we have focused on cyclohexane because of commercial availability of the corresponding deuterated compound. In preliminary studies, 2 we characterized the penetration rate of such solvent inside HIPS materials. The diffusion of cyclohexane in the polymer was found to be comparable, if slightly slower than that of cyclopentane.…”

Section: Nmr Study Of Solvent Absorptionmentioning

confidence: 99%

“…In fact, materials applied in refrigerators manufacturing are subjected to severe conditions determined by the low temperature and exposition to aggressive fluids, which could behave as solvents for the styrenic polymers. In a previous study, 2 we focused on phenomena related to the diffusion of cyclopentane and fluorinated fluids inside HIPS samples. The diffusion regime was characterized and a correlation between the extent of the rubber phase and the diffusion rate of hydrocarbon or fluorinated solvents was found.…”

Section: Introductionmentioning

confidence: 99%

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Application of magnetic resonance techniques in investigation of hydrocarbons interaction with composite polymers

Maddinelli

Montanari

Ferrando³

et al. 2006

J of Applied Polymer Sci

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Composite polymers such as high impact polystirene (HIPS) or acrylonitrile-butadiene-styrene (ABS) are widely used in manufacturing industry. In special applications, such as refrigerator liners, a good resistance to fluids aggression is required. In this study we have applied NMR and ESR techniques to investigate the effect of diffusion of fluids (light hydrocarbons) used as blowing agents for polyurethanes (thermal insulators) inside selected HIPS materials. The application of NMR relaxation analysis on materials exposed to deuterated hydrocarbons (C 6 D 12 ) allowed selective observation of rubber phase modification. Both longitudinal (T 1 ) and transversal (T 2 ) relaxation provided information on polymer chain dynamics effects, determined by solvent interactions. In fact, a consistent increase in relaxation times of polybutadiene rubber phase after solvent exposition was observed. Similar results were obtained by using hexachlorobutadiene as solvent. Another confirmation was also obtained by spin-probe ESR technique. This technique could give useful insight into the molecular mobility of the two phases of HIPS. This experimental investigation provided a clear demonstration of consistent solvent penetration inside the rubbery phase of such composite polymers.

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Section: Nmr Study Of Solvent Absorptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Application of magnetic resonance techniques in investigation of hydrocarbons interaction with composite polymers

Maddinelli

Montanari

Ferrando³

et al. 2006

J of Applied Polymer Sci

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“…Sorption methods, wherein sorption kinetics of the compound in the polymeric material is measured, make use of the relationship between the rates of sorption and of transport of the compound in the material represented by the diffusion coefficient [29][30][31][32]. Under permeation methods, the polymer material is used as a permeable membrane and the amount of compound diffusing across the membrane at a constant concentration (pressure) gradient is measured, from which the diffusion coefficient is determined [33][34][35].…”

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confidence: 99%

Emission of styrene from polystyrene foam and of cyclopentane from polyurethane foam - measurements and modelling

Choczyński¹,

Krajewska²,

Stęgowski³

et al. 2011

Polimery

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Emission of styrene from polystyrene foam and of cyclopentane from polyurethane foam -measurements and modellingSummary -Due to toxicity of volatile organic compounds (VOC), assessment of their emission from polymer dry construction materials is of importance for the quality of the indoor environment. Accordingly, in this work we studied emissions of styrene from polystyrene foam (PSf) and of cyclopentane from polyurethane foam (PURf). Both foams are common insulation materials. The partition (K) and diffusion (D) coefficients of these compounds in respective foams were determined at temperature between 23-90°C. The partition coefficients of foam-ambient gas system (K M-A ) derived from the determined adsorption and desorption rate constants (k ads , k des ) using the close-to-equilibrium theory and computer simulation, resulting in comparable values. The diffusion coefficients, by contrast, were obtained using three models based on sorption (D S ), permeation (D P ) and computer simulation (D C ). In the first model, the foam is seen as a continuous phase, in the second model -as consisting of two phases where the VOC concentration is arithmetically averaged, while the third one assumes the inhomogeneous VOC distribution. Based on the same experimental data, three sets of diffusion coefficients were obtained (D S , D P , D C ), disparate in values, these disparities originating from the assumptions made in each model. The computer-simulation at relatively low migrant concentrations in the foam (styrene-PSf system), and the permeation model at high migrant concentrations (cyclopentane-PURf system) generated the diffusion coefficients comparable with results presented in the literature.

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Nuclear Magnetic Resonance, Imaging of Polymers

Blümler¹,

Hafner²

2009

Encyclopedia of Analytical Chemistry

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Nuclear magnetic resonance (NMR) imaging is a noninvasive technique, which is based on the phenomenon of NMR. The resonance frequencies of the nuclear spins can be made spatially dependent by introducing a magnetic‐field gradient into the NMR experiment. The acquired NMR signal is thus spatially encoded and a spin‐density image of the sample can be reconstructed. While originally developed for medical applications, NMR imaging is now increasingly applied for materials investigations. The main advantages of the technique are its nondestructivity, which allows processes to be investigated in situ, and the possibility of introducing NMR spectroscopic information and relaxation contrast into the NMR images. The limitations, on the other hand, are the relatively low sensitivity and the broad NMR lines of polymers, both of which limit the spatial resolution. Whereas the latter can be dealt with by suitable methods, the sensitivity ultimately restricts the achievable spatial resolution of conventional NMR imaging techniques to about (10 µm) 3 . NMR imaging therefore must not be considered as a competitor of other microscopic techniques such as electron microscopy but as a characterization technique that provides supplementary information. Examples illustrating all these aspects are given in this article.

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Nuclear Magnetic Resonance Imaging Characterization of Resistance Properties of Polymers to Solvent Diffusion

Cited by 4 publications

References 7 publications

Application of magnetic resonance techniques in investigation of hydrocarbons interaction with composite polymers

Application of magnetic resonance techniques in investigation of hydrocarbons interaction with composite polymers

Emission of styrene from polystyrene foam and of cyclopentane from polyurethane foam - measurements and modelling

Nuclear Magnetic Resonance, Imaging of Polymers

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