Diffusion cyclopentane

The styrene monomer first may be polymerized to about 65% conversion in the absence of water, and then the blowing agent (cyclopentane) may be added with additional peroxide. This solution is suspended in water in the presence of potato starch, and the polymerization is finished (74). By another modification a styrene solution of waste polystyrene and peroxide is suspended by poly (vinyl alcohol) in water, and pentane is added to the suspension after the solids content of the oil phase is greater than 70% (133). Polystyrene particles may also be suspended in water by a mixture of poly (vinyl alcohol) and a phenyl sulfonate and then a mixture of equal parts of pentane and catalyzed styrene (8% each on polymer) is diffused into the polymer. The temperature is elevated, and the polymerization is completed (23). 

Related to the faster diffusion process for benzene and cyclopentane, where two processes exist for the other sorbates, related to the diffusion process along the straight channel direction... 

Prociak [27] studied the effect of parameters such as the method of sample preparation, the temperature gradient and the average temperature of measurement on the thermal conductivity of rigid PU foams blown with hydrocarbons and hydrofluorocarbons (HFC). The thermal insulation properties of different cellular plastics, such as rigid and flexible PU foams and expanded PS, were compared. The thermal conductivity and thermal diffusivity of foams were correlated with the PU matrix structure to demonstrate the effect of cell anisotropy on the thermal insulation properties of the rigid foams blown with cyclopentane and HFC-365/227 (93 wt% pentafluorobutane/7wt% heptafluoropropane). 

Non-polar compounds such as hydrocarbons come closest to CFCs and HCFCs and cyclopentane is nearest to the ideal (though not perfect). After optimization and adaptation to cyclopentane, foam formulations are now giving insulation values for refrigerators virtually identical to those of R 11 with similar diffusion results. The European refrigerator industry has converted to cyclopentane, and the changeover is also starting in other sectors. Safety concepts for cyclopentane are essentially based on experience with n-pentane. 

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