Premium
Reaction variables and a proposed mechanism of open‐pore urea/formaldehyde structure formation
Author(s) -
Salyer Ival O.,
Usmani Arthur M.
Publication year - 1979
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1979.070230208
Subject(s) - formaldehyde , oxide , urea formaldehyde , copolymer , urea , porosity , polymer chemistry , chemistry , materials science , colloid , chemical engineering , yield (engineering) , organic chemistry , polymer , composite material , adhesive , layer (electronics) , engineering
Formation of open‐pore urea/formaldehyde structures from nonetherified urea/formaldehyde resins involves reaction of one or more methylol groups with other methylol or amino groups. The structure formation proceeds through particle formation and growth until all the resin is consumed. A strong acid is preferred for achieving a porous structure in urea/formaldehyde resins; weakly ionized acids produce structures with low yield. Colloidal instability is an asset in porous structure formation. An 80:20 polyethylene oxide/polypropylene oxide block copolymer of approximate molecular weight 8500 has been found to be an entropic‐type destabilizer in the formation of porous structures.