Effect of the cross-linker structure of cross-linked polycarboxylate superplasticizers on the behavior of cementitious mixtures

At present, several researchers mainly focus on the synthesis of new micro-cross-linking structure, or explore the effect of cross-linkers with different molecular weight and similar structure on the performance of cross-linked polycarboxylate superplasticizers . In order to explore the influence of the different molecular structure of the cross-linker on the performance of polycarboxylate superplasticizers , two kinds of cross-linked polycarboxylate superplasticizers were synthesized in this study. These two superplasticizers incorporated either a linear cross-linker triethylene glycol diethyl ether or a cyclic cross-linker 3,9-divinyl-2,4,8,10-tetroxyspiro[5,5] undecane as one of the monomers . Then the polymers were respectively coded as SPT and SPD. Furthermore, the dispersion performance of the cross-linked polymers was evaluated by cement slurry fluidity tests and scanning electron microscopy (SEM) characterization. Consequently, cementitious mixtures incorporating SPT had better dispersibility than those incorporating conventional comb-type polycarboxylate superplasticizers (SPC) and SPD. In addition, the XRD , thermogravimetric analysis (TGA), hydration heat, and setting time tests confirmed that SPT exhibited a stronger retardation effect on cement hydration than that was provided by SPD. It was also found that SPT enhanced the compressive strength of concrete, compared to SPC and SPD. This study provides a reference for the development of cross-linked polycarboxylate superplasticizer.