Synthesis and characterization of 2-hydroxyethyl methacrylate (HEMA) modified styrene-butyl acrylate-acrylic acid emulsion polymers

In this study, a series of hydroxyl functionalized styrene (Sty)-butyl acrylate (BA)-acrylic acid (AAc) emulsion polymers were prepared via the semi-batch seeded emulsion polymerization method by using the 2-hydroxyethyl methacrylate (HEMA) monomer. The changes in the polymer latex structure, thermal behavior, film properties and morphology by increasing the HEMA content from 0 % to 10 % by mass were determined using FT-IR, 1H-NMR, TGA, DSC, MFFT, DLS and SEM techniques. In the second part of the study, changes in the properties of SBA-HEMA copolymer latex depending on the anionic/nonionic surfactant structure and amount were investigated. The addition of HEMA to the monomer emulsion was made in the feeding step after nucleation. Increasing the HEMA content from 0 % to 10 % by mass results in an increase of  10-20 C in the Tg values of the polymers. When the effect of surfactants on Tg values is investigated by keeping the amount of HEMA constant, a decrease of  1-2 C occurs in Tg values by increasing the amount of anionic surfactants SLS or SLES (according to the total monomer mass) from 0.9 % to 6 % by mass. The MFFT values for polymer latexes prepared in the studied amounts of HEMA and surfactant changes in the range of 0-7.6 C. Increasing the HEMA content from 0 % to 10 % by mass results in an increase in average particle size and PDI values indicate homogeneous distribution. The average particle size determined by DLS in one of the prepared group was 95.30 nm for SBA latex without HEMA, while it was 153.50 nm for latex containing 10 % HEMA by mass. In the latex series prepared with SLS or SLES, the particle size decreases significantly with the increasing amount of anionic surfactant, but smaller particles are formed when nonionics are used in addition. PDI data indicate that homogeneous particle distribution is decreased for SLES at 3% and higher amounts and when NP-10 is used as a nonionic surfactant.