Vapour retarders materials

The most commonly applied vapour retarder materials in lightweight envelope parts are polyethylene film and bituminous or aluminium kraftpaper. In flat membrane roofs, the bituminous membranes applied for water-tighmess are also used as a vapour retarder. A new... 

In the Belgian design guides, four vapour retarding classes have been developed, depending on the resistance to water vapour diffusion of a vapour retarder (expressed as the diffusion thickness or equivalent air layer thickness pd). Table 4.2 gives the boundaries of the vapour retarding classes, and some examples of materials. 

TVA and Differential Distillation Analysis (or SATVA) have been applied to studies on the effect of chlorinated hydrocarbon fire retardants [945, 946]. Rigby [947] has studied vapour evolution from LDPE cable insulation material (20-60 mg) by means of TVA-ToFMS, a form of in-source TD-MS, and identified Santonox R and traces of the cross-linking agent dicumyl peroxide in the low-temperature peak of the TVA curve. The TVA curves of commercial LDPE and of fl eshly prepared LDPE/Santonox suggested that in commercial samples Santonox was distributed closer to the surface than in freshly prepared ones. The detection limit (using ToF-MS) for Santonox bulk-distributed in LDPE was about 0.01%. Chiantore et al. [948] have characterised a phenol-formaldehyde (PF) resin by means of TVA (to isolate the lower-MW components) and SEC (both on volatile fractions and residues). 

Flame retardance of ethylene-vinyl acetate copolymer can be achieved using magnesium hydroxide incorporated in the polymeric matrix. The adduct of a small amount of zinc borate as synergistic agent in the formulation increases the fire-proofing properties. Multinuclei solid-state NMR appears as a means to characterise materials before and after combustion. It was shown that endothermic dehydration, water vapour evolved and formation of a glassy coating provided the flame retardancy of interest to the polymer matrix. 12 refs. EUROPEAN COMMUNITY EUROPEAN UNION FRANCE WESTERN EUROPE... 

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