| With styrene (St) as hard monomer, butyl acrylate (BA) as soft monomer, and acrylic acid (AA) as functional monomer, a styrene acrylic ester (SAE) copolymer emulsion was synthetized, and this emulsion was used combined with the oxidized starch as paper surface sizing agent. The effects of the monomer ratio (the mass ratio) on the emulsion glass transition temperature (Tg) and stability were analyzed. The results showed that the Tg rose linearly with the amount of styrene increased, and this trend was in accordance with the result of L.Mandelkern equation. With the increase of styrene dosage, the molecular weight and viscosity declined gradually, emulsion stability decreased. The properties of sized paper with the emulsion, such as water resistance, surface strength and bursting strength, were affected by the styrene content. When styrene proportion was 80% of the total monomer, surface sized with the polymer combined with oxidized starch, Cobb value of the sized paper decreased by 51.8%, surface strength and bursting strength improved by 58.0% and 5.2% respectively, compared to sized by oxidized starch. |
