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Emulsion polymerization of ethylene. III. Factors affecting the stability of polyethylene latexes
Author(s) -
Stryker Harry K.,
Helin Arthur F.,
Mantell Gerald J.
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.1966.070100106
Subject(s) - ethylene oxide , polyethylene , materials science , emulsion polymerization , polymer , particle size , emulsion , chemical engineering , particle (ecology) , coagulation , polymer chemistry , polymerization , composite material , copolymer , psychology , oceanography , psychiatry , engineering , geology
A semiquantitative method for assessing the amount of visible solid matter in polyethylene latexes is described. As judged by this method and by the presence of particles larger than 50 μ, the stability of the latexes was related to (1) the type and concentration of post‐emulsifier added to the latex, (2) the average size of the polymer particles, and (3) the concentration of solids. Generally, the appearance was better when the latexes had a low (30%) concentration of solids, a large (800 A.) average particle diameter, and enough post‐emulsifier to cover most of the polymer surface. Specific samples, however, having a high (36%) concentration of solids and a small (300 A.) average particle diameter also showed good storage stability. According to tests on selected latexes, good resistance to coagulation by mechanical shear was obtained only if the surface of the polymer was completely covered with emulsifier. When polyethoxylated alkylphenols were used as post‐emulsifiers, an inverse relation appeared to exist between latex stability and average number of ethylene oxide units per emulsifier molecule. Moreover, the addition of each ethylene oxide group increased the apparent area of the emulsifier molecule by about 4 A. 2