title: A new method for the generation of standard atmospheres of organo isocyanates.
abstract: A new and versatile method for the generation of standard atmospheres of several organo isocyanates based on permeation technique has been developed. Several membranes were screened for integrity, compatibility and permeability of these isocyanates. Silicone membrane was found to be the best membrane for the construction of permeation devices. Two types of permeation are described: liquid phase and gas phase. The liquid phase permeation tubes are recommended for generation of high concentrations (ppm) and gas phase permeation is preferred for generation of atmospheres with low concentrations (ppb). Several simple designs for construction of permeation devices are described. The permeation of isocynates were evaluated gravimetrically and were shown to be constant, provided the temperature and the flow rate of air over the permeation tube are maintained constant.
mesh_terms: D003485:Cyanates; D008567:Membranes, Artificial; D010539:Permeability; D011138:Polytetrafluoroethylene; D012828:Silicones; D014051:Toluene 2,4-Diisocyanate
chemical_list: D003485:Cyanates; D008567:Membranes, Artificial; D012828:Silicones; D014051:Toluene 2,4-Diisocyanate; D011138:Polytetrafluoroethylene