Emulsion polymerization of styrene with Iso‐octyl‐3‐mercaptopropionate as chain transfer agent

Abstract

Four batch and unseeded emulsion polymerizations of styrene were investigated, which included isooctyl 3-mercaptopropionate (iOMP) as chain transfer agent (CTA). This compound was analyzed by 13 C NMR and GC/ MS, resulting in a mixture of over 10 isomers. Because of different reactivities of the CTA isomers, the produced polystyrenes presented broad and bimodal molecular weight distributions (MWDs). A mathematical model was adjusted to the measurements, and the measured MWDs were adequately predicted when assuming the CTA as a binary mixture of high but different reactivities.

Incorporation of polybutadiene into waterborne polystyrene nanoparticles via miniemulsion polymerization

“…The highest values were obtained with the water soluble KPS initiator, and the lowest with BPO. The M w values obtained with KPS are similar to those produced in an emulsion polymerization of St with molecular weight control by chain transfer to the monomer, and particle size in the range 90-130 nm [26]. However, the low values of M n could be caused by a greater contribution of termination reactions that can take place in bigger particles nucleated from ME droplets and with higher radical concentration (Fig.…”

Toughened polystyrene nanoparticles through high-solids miniemulsion polymerization

“…For the free PS, higher molecular weights were obtained in the experiments with KPS but without CTA (PB 5 KPS 0.75 and PB 10 KPS 0.75 ), and lower molecular weights in the experiments with BPO, even with the lowest initiator concentration (0.75% wbm). The M w values obtained with KPS were similar to those produced in an emulsion polymerization of St without rubber, with molecular weight control by chain transfer to the monomer, and particle sizes in the range 90-130 nm [24]. However, the relatively lower values of M n could be due to a greater contribution of termination reactions in the larger polymer particles nucleated from miniemulsion droplets, that contain a higher radical concentration.…”

Particle Nucleation Using Different Initiators in the Miniemulsion Polymerization of Styrene

“…PS of intermediate (PS I ) and high (PS H ) molecular weights were produced under unseeded batch conditions with the recipes reported in Minari et al (2008) The measured average molecular weights ( n M and w M ), determined by SEC, of the preformed PS are summarized in Table 1. The three PS latexes were coagulated with isopropyl alcohol, and the remaining emulsifier was eliminated by successive cycles of centrifugation and redispersion with demineralized water until reaching the surface tension and conductivity of the washing water in the supernatant.…”