Octadecenylsuccinic anhydride pickering emulsion stabilized by γ-methacryloxy propyl trimethoxysilane grafted montmorillonite

Octadecenylsuccinic anhydride (ODSA) is an internal sizing agent used to hydrophobize paper and paper board in the process of papermaking. To prepare stable ODSA Pickering emulsions, montmorillonite clay-particles modified by γ-methacryloxy propyl trimethoxysilane (γ-MPTMS) were used as particulate emulsifiers of ODSA and water at room temperature. The effects of pH value, oil-to-water ratio, and particle concentration on the stability of the Pickering emulsions were investigated. The stability of ODSA emulsions in the presence of grafted-MMT first increased and then decreased as the pH value of the aqueous phase decreased. The critical pH for the phase separation of the ODSA emulsions was ∼7. Addition of ODSA oil induced phase inversion from an O/W emulsion to a W/O emulsion when the ratio of oil-to-water passed a specific threshold of 3:1 (Cp ∼ 1.5 wt%). The particle concentration was linked to the formation of particle films at oil–water interface and of clay particle networks in water phase. The ODSA emulsions stabilized by grafted-MMT could have good sizing performance and lifespan. This study on ODSA Pickering emulsions based on MPTMS-grafted MMT particles opens up a new route to the preparation of a variety of paper sizing agents in the papermaking industry.

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► The ODSA emulsions were prepared by γ-MPTMS-grafted montmorillonite.
► The critical pH value for phase separation of the ODSA emulsions is 7.
► Effective particle films and particle network were formed at Cp 1.5 wt%.
► The lifespan and hydrolysis resistance of ODSA were improved.