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Emulsion copolymerization of vinylidene chloride and butyl methacrylate, 83:17 in mol %
Author(s) -
Lee KiChang,
ElAasser M. S.,
Vanderhoff John W.
Publication year - 1991
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.1991.070421207
Subject(s) - copolymer , monomer , emulsion polymerization , materials science , polymerization , polymer chemistry , emulsion , methacrylate , glass transition , particle size , methyl methacrylate , polymer , chemical engineering , chemistry , composite material , organic chemistry , engineering
Seven 35% solids, (83 : 17 in mol %), vinylidene chloride (VDC)–butyl methacrylate (BMA) copolymer latexes were prepared at 25°C using redox catalyst by batch and seeded semicontinuous emulsion copolymerization processes: one batch (G), one seeded batch (F), and five seeded semicontinuous polymerizations of five different monomer feed rates ranging from 0.27 (A) to 1.10 (E) wt %/min. All of the emulsion polymerizations gave stable latexes of almost 100% conversion with negligible coagulum and narrow particle size distributions. The kinetic studies of seeded semicontinuous polymerization A–E showed that the rates of polymerization ( R p ) were controlled by the monomer addition rates ( R a ), and polymerizations A–D (0.27–0.79 wt %/min) were under monomer‐starved conditions; polymerization E (1.10 wt %/min) was in near‐flooded condition. Significant differences were found in the physical and mechanical properties of the latex films, depending on the mode of monomer addition. Infrared spectroscopy, 13 C solid‐state NMR spectroscopy, X‐ray diffraction, the T g and T m values by DSC, dynamic mechanical spectroscopy, and tensile strength measurement of the latex films post‐heat‐treated for 30 min at 70°C or aged for several months at room temperature demonstrated that batch polymerizations F and G gave copolymers of heterogeneous composition and a crystalline character. In contrast, semicontinuous polymerizations A–E gave copolymers of more uniform composition and an amorphous character.