부산대학교 도서관

In a conventional semi-batch seeded emulsion copolymerization of vinyl acetate/butyl acrylate (VA/BA) using hybrid surfactants namely, dioctyl sulfosuccinate (DOSS) as an anionic surfactant, nonylphenol ethoxylate (KENON 30) as a non-ionic type, and polydimethylsiloxane surfactant (having hydrophilic silanol-terminated, called PDMS). The effect of PDMS on the properties of the latex synthesized was investigated by measuring solid content, viscosity, colloidal stability, particle size distributions of the base latex, viscosity average molecular weight ( $$ \bar{M}_{\text{v}} $$ ) of the copolymer, latex particle morphology, glass transition temperature ( T ) of a copolymer and thermal gravimetric analysis (TGA). Particle size of the base latex decreases (Z-average from 246.48 to 143.69 nm) upon increasing the amount of PDMS surfactant in the recipe (up to 6 wt%). The presence of PDMS surfactant in the hybrid surfactants led to a significant increase in the solid content (from 48.71 to 51.31 wt%), viscosity (from 334 to 806 centipoise, cp) and $$ \bar{M}_{\text{v}} $$ (from 1.91 × 10 to 2.34 × 10 g mol). Thermal stability and T of the copolymer were increased with addition of PDMS surfactant (thermal stability from 344.77 to 389.81 °C and T from −20.7 to 21.7 °C). The colloidal stability evaluated using the electrolyte addition method was improved with addition of PDMS surfactant. The uniform morphological structure of the final particle is the main effect of using PDMS in the hybrid surfactants. Graphical Abstract : [ABSTRACT FROM AUTHOR]