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Some physicochemical properties of poly (ethyl acrylate) emulsions containing carboxyl groups
Author(s) -
Muroi Soichi
Publication year - 1966
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.1966.070100505
Subject(s) - methacrylic acid , conductometry , copolymer , potentiometric titration , acrylic acid , titration , polymer chemistry , polymer , acrylate , ethyl acrylate , emulsion , titration curve , equivalence point , chemistry , poly(methacrylic acid) , methacrylate , materials science , organic chemistry , inorganic chemistry , ion
Conductometric and potentiometric titration behavior of emulsions of ethyl acrylate copolymers with acrylic acid and methacrylic acid was investigated. On the conductometric titration curves of the emulsions of the copolymers with more than 5 mole‐% of the acids, two equivalence points, based on the copolymerized acids, were observed, but only one equivalence point was observed on potentiometric titration. Almost all of the copolymerized acids could be detected by both titration methods. The change in optical density of the dilute emulsions with their pH was measured. The particles of these emulsions were studied under an electron microscope. These results showed that, when the pH of the emulsions was raised, the surface layers of the particles began to dissolve and their cores started to swell near the pH of their first equivalence points. When the pH was again lowered the dissolved polymers coagulated, tiny particles were formed, and the swollen cores were dehydrated. The surface layers thickened with increasing amount of the copolymerized acid. These behaviors were very similar in the emulsions of the copolymers with acrylic acid and methacrylic acid. The quantity of water‐soluble polymers formed in the course of the emulsion copolymerization was approximately 3–4% or slightly more. This quantity depended only slightly upon the amount and type of the copolymerized acid. The acid contents of the water‐soluble polymers were higher in cases of the copolymers with acrylic acid than in those with methacrylic acid. No relationship with the amount of copolymerized acid was established.