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Compatibility studies on polyacrylate and polymethacrylate systems
Author(s) -
Hughes L. J.,
Britt G. E.
Publication year - 1961
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.1961.070051514
Subject(s) - miscibility , polymer , copolymer , polymer chemistry , methacrylic acid , solvent , monomer , hydrogen bond , methacrylate , acrylate , materials science , acrylic acid , polyelectrolyte , chemical engineering , chemistry , organic chemistry , molecule , engineering
The predicted general incompatibility of mixtures of polymers has been further confirmed. Thirty‐one mixtures of homopolymer pairs showed phase separation in a common solvent. These included closely related polymers such as polyacrylates with both polymethacrylates and other polyacrylates and pairs of different polymethacrylates. Typical immiscible combinations are PMA/PEA and PEMA and PEMA/PMMA. It was also found that the presence of a common monomer constituent did not result in complete compatibility of either a homopolymer with a copolymer or a mixture of two copolymers. Apparently, none of the combinations tried were sufficiently similar to result in heats of interaction small enough to be counteracted by the small entropy change involved. Since another possibility for attaining miscibility is through polar interactions, the effects of ionic and hydrogen‐bonding substituents upon polymer‐polymer compatibility were considered, and selected experiments were done on a series of carboxyl‐containing polymers and their sodium salts. It was concluded that hydrogen bridging occurs preferentially either intramolecularly or between polymer and solvent rather than between two different types of chains each having hydrogen‐bonding ability. Thus, poly(acrylic acid) and poly(methacrylic acid) show two‐phase separation in water. Although poly(sodium acrylate) and poly(sodium methacrylate) are completely miscible, mixtures of the partially neutralized acids, e.g., PAA and PNaMA mixtures, show separation. In contrast to predictions for less polar polymers, compatibility of mixtures of polymers containing high mole fractions of carboxylic acid monomers showed a pronounced dependence upon solvent. Thus, the two copolymers 45/53 EA–MAA and 47/53 MMA–MAA are incompatible in methanol or ethanol but form homogeneous solutions in DMF or DMS.