Permeation of water vapor through high performance laminates for VIPs and physical characterization of sorption and diffusion phenomena

Abstract

a b s t r a c tMaintaining the long term performance of vacuum insulation panels (VIPs) remains the focus of many technical and scientific investigations. The performance of the barrier laminate is decisive to hold the vacuum level and to resist the permeation of water vapor. This barrier property against water vapor is characterized by the permeance of the laminate. The permeance of several commercially available products was determined by different methods and a good correlation was obtained between the manometric method on laminates and the current reference method on VIPs (weight gain in climatic chambers).Even if the permeance is appropriate to evaluate the performance of VIPs under stationary conditions, the solubility and diffusion coefficients are required for a fine-tuned service life prediction under real climatic loading conditions. Whereas for the PET the absorption isotherm is linear up to high humidity levels, this is not the case for the sealing layers, nor for the laminates. But this deviation from Henry's law does not impact the modeling of the behavior of current laminates because only the external PET layer is exposed to high humidity. The activation energies of sorption and diffusion have been evaluated. The experimental results on metalized and non metalized PET films confirm that the temperature dependence of the diffusion and of the permeance is driven by the behavior of the polymer.

The Use of Sorption Balance for the Characterization of the Water Retention Curve of Cement-Based Materials

“…Sorption balances have existed for a very long time (McBain and Bakr 1926;Gregg and Wintle 1946;Gregg 1955;Gleeson 1962;Tamburini 1970) however now, there are reliable models available from numerous suppliers (Keller and Robens 2003). They are especially and commonly used in various scientific fields: pharmaceuticals, the food industry or the study of materials (Cazacu et al 2009;Lyn et al 2010;Ayadi and Dole 2011;Maeda et al 2011;Wicklein et al 2011;Argyropoulos et al 2012;Carter and Schmidt 2012;Pei and Zhang 2012;Volkova et al 2012;Zhang et al 2012;Besbes et al 2013;Jung et al 2014;Pons et al 2015;Mette et al 2014;Guicheret-Retel et al 2015;Otoni et al 2016). In these areas it has been proven that the use of sorption balance is able to obtain similar results to other common techniques (Johannesson and Janz 2002;Arlabosse et al 2003;Fei et al 2006).…”

VIP service life assessment: Interactions between barrier laminates and core material, and significance of silica core ageing

“…• Q ı,w derived from the authors' measurements on commercial barrier laminates: 26 kJ/mol [2]. • Q ı,a of air permeation in crystallized PET chosen equal to that of oxygen: 30 kJ/mol [5].…”

“…As a consequence accurate service life assessment of VIP in many real conditions is only possible with dynamic diffusion and solubility models fed with accurate physical data. Determining such data for water vapour is the aim of another paper of the team [2].…”

Durability of Polymer Metal Multilayer: Focus on the Adhesive Chemical Degradation

“…The latter provides high bond strength and some barrier performance (Brunner et al, 2006; Brunner and Simmler, 2008). Numerous studies have already been carried on the optimization of the number of layers, their compositions, layouts, and thicknesses (Simmler and Brunner, 2005; Baetens et al, 2010; Garnier et al, 2011; Miesbauer et al, 2014; Pons et al, 2014). At present, they are many different multilayer laminates on the market that include up to more than ten layers and three adhesive layers.…”