Voronova Marina I, Surov Oleg V, Afineevskii Andrei V, Zakharov Anatoly G
Laboratory of Physical Chemistry of Polymer-Liquid Heterogeneous Systems, G.A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, 1 Akademicheskaya St., Ivanovo 153045, Russian Federation.
Department of Physical and Colloid Chemistry, Ivanovo State University of Chemistry and Technology, 7 Sheremetevsky Prospekt, Ivanovo 153000, Russian Federation.
Heliyon. 2020 Nov 18;6(11):e05529. doi: 10.1016/j.heliyon.2020.e05529. eCollection 2020 Nov.
In this work, a series of polyacrylamide/cellulose nanocrystal (PAM/CNC) composites with a wide range of compositions were prepared by a solution casting method. Subsequently, the influence of the PAM conformation on the behaviour of the PAM/CNC composites was studied. The microstructural, thermal, and mechanical properties of the PAM/CNC composites were also investigated, as well as their flocculation and dispersion behaviour. Thermal degradation of both CNC and PAM in the composites occurred simultaneously, at a much higher temperature than the degradation of the neat CNC. By TEM and SEM, PAM globule aggregates in the PAM/CNC composites were detected. With an increase in the medium acidity, the PAM globule aggregate size of in the composites decreased. Moreover, the composite films cast from high pH solutions (extended PAM conformation) exhibited superior strength properties than those cast from low pH solutions (contracted coil PAM conformation). The PAM globule conformation provided good re-dispersibility of the freeze-dried PAM/CNC composites by preventing aggregation of the CNC particles. The PAM globule adsorption onto the CNC particles caused CNC surface hydrophobization and a decrease in their surface charge, while maintaining high colloidal stability of the CNC suspensions. Furthermore, the CNC particles with adsorbed PAM were demonstrated to be useful as emulsifiers and compatibilisers.
在本工作中，通过溶液浇铸法制备了一系列具有广泛组成的聚丙烯酰胺/纤维素纳米晶体（PAM/CNC）复合材料。随后，研究了PAM构象对PAM/CNC复合材料性能的影响。还研究了PAM/CNC复合材料的微观结构、热性能和力学性能，以及它们的絮凝和分散行为。复合材料中CNC和PAM的热降解同时发生，且温度远高于纯CNC的降解温度。通过透射电子显微镜（TEM）和扫描电子显微镜（SEM），检测到PAM/CNC复合材料中的PAM球粒聚集体。随着介质酸度的增加，复合材料中PAM球粒聚集体的尺寸减小。此外，由高pH溶液浇铸的复合薄膜（伸展的PAM构象）比由低pH溶液浇铸的复合薄膜（收缩的卷曲PAM构象）表现出更好的强度性能。PAM球粒构象通过防止CNC颗粒聚集，为冻干的PAM/CNC复合材料提供了良好的再分散性。PAM球粒吸附到CNC颗粒上导致CNC表面疏水化并降低其表面电荷，同时保持CNC悬浮液的高胶体稳定性。此外，吸附有PAM的CNC颗粒被证明可用作乳化剂和增容剂。
