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Chlorine exchange resins, effects of resin formulation on exchange properties
Author(s) -
Dewar E. J.,
Wayman M.
Publication year - 1970
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450480605
Subject(s) - chlorine , chemistry , diffusion , ion exchange resin , condensation , chemical engineering , formaldehyde , polymer chemistry , absorption of water , synthetic resin , polymerization , organic chemistry , polymer , materials science , composite material , thermodynamics , physics , engineering
Chlorine exchange resins prepared from urea, melamine and formaldehyde in various ratios and under various conditions were found to vary widely in physical structure, diffusion coefficients and capacity to absorb chlorine. Resins prepared by relatively intensive heating of the methylol syrup, or by condensation at relatively high pH, about 5, or by condensation at low temperature appeared to undergo some phase separation resulting in an opaque white resin with a macroreticular structure. Such resins had good physical stability. The opaque, porous, macroreticular resins generally had higher effective diffusion coefficients, but lower chlorine absorption capacity, than the relatively uniform translucent resins. An increase in the water content of the resin from 50 to 65% resulted in an increase in the effective diffusion coefficient (D̄) by a factor of 3, and a small increase in chlorine capacity. D̄ was a maximum when the pH of the chlorinating solution was about 3, suggesting that HOCl is the diffusing species. The production of these resins in bead form by suspension polymerization is described.