Premium
A new method to determine monomer concentration in the polymer particles of emulsion polymerization systems by dynamic light scattering
Author(s) -
Abdollahi Mahdi,
Hemmati Mahmoud
Publication year - 2009
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.30590
Subject(s) - potassium persulfate , monomer , emulsion polymerization , polymer chemistry , polymerization , dispersity , polymer , dynamic light scattering , materials science , styrene , precipitation polymerization , methacrylic acid , radical polymerization , particle (ecology) , chemical engineering , chemistry , copolymer , nanoparticle , oceanography , geology , engineering , composite material , nanotechnology
Emulsifier‐free emulsion polymerization of styrene was performed in the presence of small amount of methacrylic and itaconic acids as carboxylic acid monomers and potassium persulfate as an initiator at 70°C to prepare monodisperse polymer particles. Diameter of monomer swollen polymer particles ( d pswol ) was measured by dynamic light scattering for samples taken from the reaction mixture during the Intervals II and III of the emulsion polymerization. Graphically treatment of d pswol versus conversion data allowed us for the first time to directly determine the critical monomer conversion ( x c ), from which constant monomer concentration in the polymer particles ( C MP ) during the Interval II was then calculated. x c and C MP were obtained to be 0.379 and 5.68, respectively. C MP value is in good agreement with that obtained by centrifugation method and those reported in the literature for the similar system. Attempts were also made to evaluate the average number of growing chain per particle ( $\overline n$ ) during the Interval II of emulsion polymerization of styrene. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009