Alkenyl succinic anhydride (ASA) is widely used in papermaking industry as an internal sizing agent. In situ emulsification of ASA using cationic starch is conventionally practiced because of the low shelf life of ASA emulsion. We synthesized Janus particles by surfactant-free seeded polymerization to stabilize ASA emulsion. The morphology evolution and anisotropic compositions of Janus particles were confirmed by transmission electron microscopy. The Janus particles showed a strong tendency to adsorb at the ASA–water interface and enhanced the stability of ASA emulsion. The droplet size of ASA emulsion decreased and emulsion phase volume increased with the concentration of Janus particles increased. In comparison with cationic starch, Janus particles exhibited superior emulsification performance in ASA emulsion. The ASA emulsion stabilized by Janus particles was used as an internal sizing agent for cellulose paper. The results of sizing degree and Cobb30 showed that the sizing performance of ASA emulsion stabilized by Janus particles was significantly improved. Our study provides a better choice of preparing ASA emulsion for paper sizing and promotes the application of Janus materials in paper industry.

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中文翻译：

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Janus颗粒稳定链烯基琥珀酸酐乳液作为内施胶剂

烯基丁二酸酐（ASA）广泛用于造纸工业作为内施胶剂。由于 ASA 乳液的保质期短，通常使用阳离子淀粉原位乳化 ASA。我们通过无表面活性剂种子聚合合成了 Janus 粒子以稳定 ASA 乳液。Janus粒子的形态演变和各向异性成分通过透射电子显微镜得到证实。Janus 颗粒在 ASA-水界面表现出强烈的吸附倾向，增强了 ASA 乳液的稳定性。随着Janus粒子浓度的增加，ASA乳液的液滴尺寸减小，乳液相体积增加。与阳离子淀粉相比，Janus 颗粒在 ASA 乳液中表现出优异的乳化性能。由 Janus 颗粒稳定的 ASA 乳液用作纤维素纸的内部施胶剂。施胶度和Cobb30结果表明，Janus颗粒稳定的ASA乳液的施胶性能显着提高。本研究为制备造纸施胶用ASA乳液提供了更好的选择，促进了Janus材料在造纸工业中的应用。

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