In this study, styrene 70 wt.%-butyl acrylate 30 wt.% copolymer-based surface-sizing materials were synthesized using semi-batch emulsion polymerization and applied on the paper. Four different emulsifiers, with different ethylene oxide numbers, at ratios of 10%, 7% and (2, 2'-azobis (2-methylpropionamidine) dihydrochloride (A)) as initiator were used for emulsion polymerization. Eight different copolymers were synthesized. Synthesized copolymers were used as surface sizing agents for the paper surface. Ion exchange capacity, pH, Fourier transform infrared spectroscopy, differential scanning calorimetry and thermal gravimetric analysis were used for the characterization of the copolymer properties. Contact angle measurements, Cobb test, and scanning electron microscopy analysis were carried out to determine the surface properties of the paper samples. Presence of copolymer formations was proven with the Fourier transform infrared analysis. Contact angle measurements of the copolymer sized paper surface have shown hydrophobic behaviour in samples, with the exception of E-3/7/A sample. The lowest Cobb value was observed for E-2/7/A sample. The highest thermal stability was also observed for E-2/7/A sample. The scanning electron micrographs show that the paper loses its fibrous structure and it is seen that the copolymer adheres to the fibrous tissue.