caa a22 4500 475763718 CHVBK 20180406123558.0 cr unu---uuuuu 170329e20000901xx s 000 0 eng 10.1007/s003960000337 doi (NATIONALLICENCE)springer-10.1007/s003960000337 Emulsifier-free emulsion copolymerization of styrene and acrylamide using an amphoteric initiator [Elektronische Daten] [S.-J. Fang, K. Fujimoto, S. Kondo, K. Shiraki, H. Kawaguchi] Emulsifier-free emulsion copolymerization of styrene (St) and acrylamide (AAm) has been investigated in the presence of an amphoteric water-soluble initiator, 2,2′-azobis[N-(2-carboxyethyl)-2-2-methylpropionamidine]hydrate (VA057). The kinetics of polymerization and the colloidal properties of the resulting latices were studied and compared with the cases using ionic initiators. When adopting the amphoteric initiator at pHs lower than 10, stable amphoteric poly (St/AAm) latices, evidenced by the electrophoretic mobility, were prepared directly. Meanwhile, almost the same conversion versus time curves appeared and there were no apparent differences in the final particle sizes for those polymerizations, whereas in the polymerization at pH 10, a much lower rate of copolymerization and a larger size of particles were observed. The surface charge density and the growth rate of latex particles produced with VA057 at pH<10 were comparable to those of the particles with a cationic initiator, 2,2′-azobis(2-amidinopropane)dihydrochloride, but were apparently lower than those with an anionic initiator, potassium persulfate, when the polymerizations were carried out under corresponding conditions. The number of initiator fragments incorporated onto the particle surfaces was independent of polymerization pH, except for pH 10. The abnormal performance of VA057 at pH 10 was attributed to its degradation due to hydrolysis. Springer-Verlag Berlin Heidelberg, 2000 Key words Emulsifier-free emulsion polymerization nationallicence Amphoteric initiator nationallicence Amphoteric latex nationallicence Styrene nationallicence Acrylamide nationallicence Fang S.-J Department of Applied Chemistry Faculty of Science & Technology Keio University, 3-14-1, Hiyoshi Kohoku-ku, Yokohama 223-8522, Japan e-mail: haruma@applc.keio.ac.jp Fax: +81-45-5645095, JP aut Fujimoto K. Department of Applied Chemistry Faculty of Science & Technology Keio University, 3-14-1, Hiyoshi Kohoku-ku, Yokohama 223-8522, Japan e-mail: haruma@applc.keio.ac.jp Fax: +81-45-5645095, JP aut Kondo S. Central Laboratory Wako Pure Chemicals Industries Ltd Kawagoe, Japan, JP aut Shiraki K. Central Laboratory Wako Pure Chemicals Industries Ltd Kawagoe, Japan, JP aut Kawaguchi H. Department of Applied Chemistry Faculty of Science & Technology Keio University, 3-14-1, Hiyoshi Kohoku-ku, Yokohama 223-8522, Japan e-mail: haruma@applc.keio.ac.jp Fax: +81-45-5645095, JP aut https://doi.org/10.1007/s003960000337 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s003960000337 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Fang S.-J Department of Applied Chemistry Faculty of Science & Technology Keio University, 3-14-1, Hiyoshi Kohoku-ku, Yokohama 223-8522, Japan e-mail: haruma@applc.keio.ac.jp Fax: +81-45-5645095, JP aut NATIONALLICENCE 700 1- Fujimoto K. Department of Applied Chemistry Faculty of Science & Technology Keio University, 3-14-1, Hiyoshi Kohoku-ku, Yokohama 223-8522, Japan e-mail: haruma@applc.keio.ac.jp Fax: +81-45-5645095, JP aut NATIONALLICENCE 700 1- Kondo S. Central Laboratory Wako Pure Chemicals Industries Ltd Kawagoe, Japan, JP aut NATIONALLICENCE 700 1- Shiraki K. Central Laboratory Wako Pure Chemicals Industries Ltd Kawagoe, Japan, JP aut NATIONALLICENCE 700 1- Kawaguchi H. Department of Applied Chemistry Faculty of Science & Technology Keio University, 3-14-1, Hiyoshi Kohoku-ku, Yokohama 223-8522, Japan e-mail: haruma@applc.keio.ac.jp Fax: +81-45-5645095, JP aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer