Influence of polymer variation on the flexural property and microstructure of biomimetic cement-based materials

Biomimetic cement-based materials inspired by natural nacre have been developed via the bionic structure design and polymer toughening. Previous studies indicate that the mechanical property of this material is dominated by the quality of brick-and-mortar structure and the internal and external polymer. Herein, the flexural property and microstructure of biomimetic cement-based materials containing different polymers are comprehensively investigated, in order to clarify the influence of polymer variation on the strength and toughness evolution. Compared with the control group, changes of internal polymers slightly affect the flexural properties of materials, while changes of external polymers demonstrate significant impacts. The internal polymers exhibit differences in the intrinsic toughening mechanisms, which affect the ductile fracture of materials. And the fracture behaviors are largely altered by external polymers, which can be attributed to the film formation characteristics of polymer emulsions and the tensile properties of polymer films. Moreover, the differences in chemical interactions between polymers and cement matrix can strongly affect the flexural strength and toughness of materials. This work can provide theoretical bases for the polymer selection and performance enhancement of biomimetic cement-based materials.