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The molecular structure, rheological properties, microstructure and physical stability of oil-in-water emulsions using octenyl succinic-sugary maize soluble starch (OS-SMSS) were investigated and compared with two commercial OS-starches (HI-CAP 100 and Purity Gum 2000). The degree of substitution (DS), weight-average molecular weight (Mw) and z-root mean square radius of gyration (Rz) of OS-SMSS, HI-CAP 100 and Purity Gum 2000 were 0.0050, 223.4 × 10 5 g/mol and 38.8 nm, 0.0037, 9.6 × 10 5 g/mol and 29.3 nm, and 0.0031, 31.3 × 10 5 g/mol and 39.6 nm, respectively. FT-IR spectra showed two new absorption bands at 1725 and 1570 cm −1 from OS ester linkage in all tested samples. The emulsion with OS-SMSS exhibited a pseudoplastic behavior over the whole shear rate range, whereas other two emulsions showed a similar Newtonian fluid. All hydrophobic starch stabilized emulsions satisfied the Herschel–Bulkley model. All emulsions displayed storage modulus (G′) was higher than loss modulus (G″), and only G′ and G″ of OS-SMSS stabilized emulsion were independent of frequency. The volume-average droplet size ( d 43 ) value of emulsions stabilized by three modified starches was 27.9, 15.2 and 24.4 μm, respectively. During 4 weeks storage, lower change in d 43 of emulsion with OS-SMSS was observed. The above results with schematic models of emulsions suggested that an emulsion with high stability could be prepared using 3% of OS-SMSS due to the formation of high density and thick nanoparticle layer at the interface, indicating OS-SMSS was a Pickering emulsion stabilizer for good long-term stability. [ABSTRACT FROM AUTHOR]

Water-in-oil emulsions are frequently encountered in petroleum extraction. In this paper, CRB-SiO 2 , a cost-efficient and environmentally friendly demulsifier, was synthesized by a two-step method. The chemical structure and surface morphology were analyzed by flourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM), respectively. The effect of salinity, concentration, temperature and pH value on the demulsification efficiency (DE) was investigated in detail. The DE reached 93.98% with 600 mg/L of CRB-SiO 2 at 70 °C. Also, it had an excellent tolerance of salt, acid and alkali. Moreover, the demulsification mechanism was also studied through three-phase contact angle, interfacial tension and self-assembly of interfacial membrane. CRB-SiO 2 has an amphiphilic structure and lower interfacial tension (IFT) around 37.75 mN/m. Accordingly, it can be easily adsorbed at the water-oil interface, destroying the interface membrane and initiating the separation of oil and water. In summary, CRB-SiO 2 has a potential application in petrochemical industry. [Display omitted] • CRB-SiO 2 was prepared by a two-step method. • CRB-SiO 2 has high demulsification efficiency in water-in-crude oil emulsion. • CRB-SiO 2 is environmentally friendly and highly economical because it uses waste rice bran as raw material. • CRB-SiO 2 has an excellent tolerance of salt, acid and alkali. • The demulsification mechanism has been deeply studied from many aspects. [ABSTRACT FROM AUTHOR]