β-Cyclodextrin Substituted Polyoxyethylene in the Synthesize of Polycarboxylate Superplasticizers

In this study, the starch-based material β-cyclodextrin was used as the original material to substitute petrochemical product-polyoxyethylene (HPEG) to synthesize concrete admixture polycarboxylate superplasticizer (PCE). During the synthesis, β-cyclodextrin was first grafted on the PEO chain to prepare β-CD-HPEG by click reaction. Then β-CD-HPEG was used to substitute the macromonomer HPEG to synthesize β-CD-PCE. When the substitution amount HPEG was 3%, the synthesized β-CD-PCE showed better dispersion ability.

Study on the Synthesis, Properties and Characterization of EPEG Slump Retaining Typed Polycarboxylate Superplasticizer

The ethyl glycol vinyl ether polyoxyethylene ether (EPEG) is a new type of macromonomer to synthesize polycarboxylate superplasticizer (PCE), which has higher reactivity due to the unsaturated double bond and easily to polymerization. The EPEG slump retaining typed PCE can be synthesized by free radical polymerization though EPEG, acrylic acid and hydroxyethyl acrylate (HEA). The HEA had the greatest influence on slump retaining performance. High polymerization conversion rate of EPEG typed PCE was beneficial to improve the concrete performance.

Effect of Ether-Typed Polycarboxylate Superplasticizer on the Adsorption, Rheology and Concrete Properties

This article disclosed the influence of acid-ether ratio, n(SH)/n(IPEG), and n(APS)/n(IPEG) on adsorption and fluidity performance. The optimum synthetic parameters of acid-ether ratio, n(SH)/n(IPEG) and n(APS)/n(IPEG) were 0.5, 0.35 and 0.05, respectively. The rheology fitting equation was τ= 719.55γ+ 1834.54. And the correlation coefficient was 0.9843. The cement paste conformed to the law of pseudoplastic fluid. The preferred PCE-11 had excellent performance in freshly mixed and hardened concrete.

Study on adsorption, rheology and hydration behaviours of Polycarboxylate(PCE) superplasticizer synthesized by different acid to ether ratio

Polycarboxylate superplasticizer is synthesised by different acid to ether ratio, which is changing the main chain structure parameters, obtained different microstructures. The effect of different microstructure PCE superplasticizer on the fluidity of cement paste, rheological thixotropy, adsorption capacity and hydration heat are studied. The results show that dispersing performance in cement with acid to ether ratio of 3.5 is the best, the molecular weight and side chain density have rather little effect on the cement hydration process.

The influence of the structural parameters of polycarboxylate superplasticizer on the dispersion and adsorption

Polycarboxylate superplasticizers with different structural parameters were synthesized by isobutylene polyoxyethylene ether, acrylic acid and ammonium persulfate as raw materials from the perspective of molecular design. The influence of polycarboxylate superplasticizer on cement adsorption was characterized by cement adsorption capacity test and fluidity test, etc. At the same time, the adsorption change of polycarboxylate superplasticizer on the surface of cement particles was also revealed. It was found that the best adsorption and dispersion properties on cement paste were obtained under the heating synthesis process when the structure of the water reducing agent was designed to have a weight average molecular weight of 55128, a macromonomer conversion rate of 84.61%, and a side chain density of 0.1725. For the normal temperature process, when the weight average molecular weight was 103920, the macromonomer conversion rate 92.03%, and the side chain density 0.3115, the best effects in cement can be achieved.