Synthesis of Polybutadiene Nanoparticles via Emulsion Polymerization: Effect of Reaction Temperature on the Polymer Microstructure, Particle Size and Reaction Kinetics

Polybutadiene nanoparticles were synthesized via batch emulsion polymerization of butadiene in the presence of potassium persulfate, disproportionate rosinate potassium cation and t-dodecyl mercaptane as initiator, emulsifier and chain transfer agent, respectively. Polymerization reaction was performed at different temperatures (60, 70 and 80 C). Conversion was measured at various time intervals by gravimetry method. Particle size and its distribution of the polybutadiene latex were measured by dynamic light scattering (DLS) and SEM analyses. Polymer microstructure was investigated by FT-IR spectroscopy. By increasing the polymerization temperature, average diameter of the polybutadiene nanoparticles decreased from 104 nm (at final conversion of 80.6%) at 60 oC to 88.7 nm (at final conversion of 98.0%) at 80 oC. Dominant microstructure, i.e. 1,4-trans isomer content, in the synthesized polymers was calculated to be about 60%. Results showed that by increasing the reaction temperature, size of the particles decreased while the number of the polymer particles and polymerization rate increased.