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Crystallization of carboxylic acid salts in poly(ethylene oxide) oligomers at higher temperatures
Author(s) -
Ohno Hiroyuki,
Kawanabe Hisashi,
Ito Kaori
Publication year - 1995
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.1995.220060405
Subject(s) - alkyl , solubility , ethylene oxide , crystallization , carboxylate , salt (chemistry) , materials science , alkali metal , oxide , phase (matter) , polymer chemistry , chemistry , organic chemistry , polymer , copolymer
Many alkali metal carboxylates when dissolved in poly(ethylene oxide) (PEO) oligomers, are phaseseparated by heating. These were revealed to be the crystals of the initially dissolved corresponding salts from the X‐ray diffraction patterns. Some acetate salts achieve the lower limit of the lattice energy for phase separation of ordinary inorganic salts by heating in PEO oligomers. These carboxylate salts were therefore expected to show crystallization behavior in PEO oligomers by heating. The effects of cation size, alkyl chain length and molecular weight of PEO on the solubility are summarized. Negative temperature dependence of solubility of these acetate salts is seen in the PEO oligomers only when the salts have long alkyl chains. The salts containing larger cations needed a longer chain length of PEOs for crystallization by heating. These salts with longer alkyl chains showed positive temperautred dependence in lower molecular weight polyethers, but negative temperature dependence in solubility in PEO with molecular weights higher than 400. In PEO 400 , all the carboxylates with longer alkyl chains were phase separated by heating.