Preparation and Application of New Polycarboxylate Superplasticizers with Mild Retarding Performance Based on Monovinyl β-Cyclodextrin Monomer

Abstract

Based on monovinyl b-CD monomer (GCD), random copolymers (PTCDs) were first synthesized by AA, TPEG, and GCD, and characterized by FTIR and GPC. The application performances of PTCDs as superplasticizers in cement and concrete were investigated considering dispersion, adsorption, setting times, and compressive strength. The results indicated that PTCDs had more excellent applied performance compared with AA-co-GCD copolymers, and the outstanding feature is that PTCDs had a mild tunable retarding effect. When with certain amount of CD pendants and PEO side chains, PTCD 2 had the best dispersion and mild retarding performances, which were mainly attributed to the joint steric hindrance effect provided by CD pendants and PEO side chains. This study offers a new type of superplasticizer from CD and its derivatives with excellent dispersion and retarding performances to concrete engineering.

Synthesis of polycarboxylate superplasticizer modified by β‐cyclodextrin for possessing clay tolerance

“…It is a cyclic oligosaccharide and has hydrophilic outer surface and hydrophobic inner cavity. Recently, some researchers had applied β ‐CD in the modification of PCE to lower the clay sensitivity and obtain a better dispersing performance for cement 22–24 . For example, Xu modified TPEG‐type PCE with ‐CD, and then tested its clay tolerance property by measuring the fluidity of cement paste as adding Ca‐montmorillonite.…”

“…Recently, some researchers had applied β-CD in the modification of PCE to lower the clay sensitivity and obtain a better dispersing performance for cement. [22][23][24] For example, Xu modified TPEG-type PCE with β-CD, and then tested its clay tolerance property by measuring the fluidity of cement paste as adding Ca-montmorillonite. The results showed that the fluidity of cement paste was considerably increased.…”

Poly(Ethylene Glycol)/β-Cyclodextrin Pseudorotaxane Complexes as Sustainable Dispersing and Retarding Materials in a Cement-Based Mortar

“…The wide expansion of CDs was made possible by their low-cost production on an industrial scale. CD-based polymers, in which the CDs are covalently grafted on a polymeric backbone, have found interesting applications as a concrete water-reducing agent [also named as superplasticizers (SPs)]. − SPs − play a crucial role in modern concrete technology because they guarantee good fluidity of cement pastes and control their setting time, even at low water/cement ratios. − Among the SPs of first generation, the sulfonated additives such as poly-β-naphthalene sulfonate (SNF) − and polymelamine sulfonate (SMF) − have found wide applications. Polycarboxylate ether (PCE) SPs show superior performance in cement-based mortars.…”

“…In the past years, increasing attention has been devoted to designing ecofriendly SPs, and among them, β-CD-based dispersants have been playing a crucial role. − …”

“…The dispersing abilities of β-CD-based SPs is due to the steric hindrance between the truncated-cone macrocycles and the electrostatic repulsion between anionic groups of the polymer adsorbed on the surface of cement particles. − Very recently, we have found out that water-soluble resorcin[4]­arene and pyrogallol[4]­arene macrocycles show an analogous behavior and are able to work as dispersing agents but show retarding effects in cement-based mortars.…”