Preparation and Evaluation of Polyuretham Foam/Rubber Membrane-Based Samplers for use in Isocyanate Sampling

Abstract

In order to collect isocyanate in both aerosol and vapor forms, we have developed a dual-membrane sampler which features a moist porous bed, backed up by an impermeable membrane. A polyester-polyurethane foam (PUF) was selected to function as the porous bed, and it was evaluated for its ability to resist solvent RUDZlNSKl ET AL. degradation and swelling while permitting rapid air penetration. Natural rubber (NR) and styrene-butadience rubber (SBR) membranes were prepared to serve as backup membranes. These were also evaluated for their solvent compatibility and air-penetration characteristics. A polyester-polyurethane foam backed up by a NR membrane prepared by an efficient vulcanization procedure was selected as the best combination for development of the isocyanate sampler. Recovery studies using the hexamethylenebased polyisocyanate, biuret, indicate better than 80% recovery of polyisocyanate after application to the PUF.

Sorption of Aromatic Hydrocarbons into Styrene Butadiene Rubber/Poly(ethylene-co-vinyl acetate) Blends

“…The molar equilibrium sorption coeffi cient (K s ) is a thermodynamic constant and is defi ned as 39 K s = Number of moles of penetrant sorbed Unit mass of the blend (14) The K s value is a measure of the solvent uptake by the blend system and is used for the calculation of entropy change, ΔS and enthalpy change, ΔH s using the Van't Hoff's relation 40 log K s = ∆S 2.303R − ∆H s 2.303RT (15) The values of ΔS and ΔH s are given in Table 10.…”

“…The sorption and diffusion of penetrants through macromolecules is controlled by factors such as polymer structure 6 , crosslink density 7 , fi llers 8 , shape and size of penetrant molecules 9 and temperature 10 . Previous studies by our group have reported various investigations into polymer-solvent interactions [11][12][13][14][15] . In blends, the transport behaviour depends on the miscibility of the component polymers as well as on the morphology of the system 16 .…”

Cellular Rubbers. A Review

“…Owing to the high absorption capacity of open-pore cellular rubbers, they are used in the joints of building constructions to absorb water [56]. A system of polyurethane foam filled with a solution of 1-(2methoxyphenyl)piperazine and a rubber membrane captures up to 80% isocyanate from the air [88]. Cellular rubbers based on polychlorobenzene, butadiene-styrene rubber, butyl rubber, and an octenomer, filled with kaolin, SiO 2 , and talc (40-100 parts), resistant to Cl 2 , are used to shield chlorine-producing electrolysers [89].…”