Preparation and Properties of Different Polyether-Type Defoamers for Concrete

Abstract

In this study, a series of polyether-type defoamers for concrete which consist of the same alkyl chain (hydrophobic part) but different polyether chains (hydrophilic part) was prepared, and the structure–property relationship of the defoamers was investigated for the first time. Using oleyl alcohol (OA) as the starting agent (alkyl chain), the polyether defoamers with different polyether chains were prepared by changing the amount and sequence of ethylene oxide (EO) and propylene oxide (PO) units. The properties of different defoamers were tested in aqueous solutions, and fresh and hardened mortars; the structure–property relationship of the defoamers was thus studied. The results indicated that the defoaming capacity of the polyether defoamers decreased with an increased EO amount, and the defoamers linked with both EO and PO units (PO before EO) had a stronger defoaming capacity than those linked with EO only. This study is beneficial for the development and applications of novel synthetic polyether-type defoamers for concrete.

Synthesis of new defoamer agents and characterization of cementitious formulations

“…This air amount can increase the workability but an air content higher than 3 % leads to worse performance, hence it should be avoided [ 7 ]. For this reason, defoamers are needed since they can enhance the mechanical properties and durability of concrete by reducing bubbles and optimizing pore structure [ 8 ]. However, the addition of the antifoam agent to a superplasticizer aqueous solution leads to phase instability.…”

Multibranched Molecule Defoamers Based on Methyl Gallate for Highly Effective Defoaming and Antifoaming

“…There are mainly six types of commonly used defoamers, including natural products (such as mineral oils), polyethers, silicones, alkyl phosphates, polyetheramines, and polyether-modified silicones. − Among them, silicone-based emulsion-type defoamers have become one of the most popular categories in the field because of their high-branched structure and high interfacial activity, relatively better water solubility and compatibility with other admixtures, and excellent bubble-capturing ability for most foam systems. ,, Nevertheless, silicone compounds are generally more costly, and their high chemical stability leads to nondegradability; hence, they are increasingly unable to meet the growing environmental and safety requirements. − Therefore, the exploration of the nonsilicone active component as the core material of defoamers, whether from the economic, environmentally friendly, or intrinsically safe consideration, is an urgent need of the defoamer industry.…”

Novel Slow-Release Defoamers for Concrete Using Porous Nanoparticles as Carriers

“…In addition, with the development of the economy and the improvement of public aesthetics, requirements for the appearance of hardened concrete are becoming more strict. An excess of large air bubbles could induce a honeycomb-pockmarked surface of hardened concrete, which may cause a defective appearance and shorten the service life of a building [6,7]. Therefore, in order to solve the problem of honeycomb-pockmarked surfaces and to improve the mechanical performance and extend the service life of concrete, it is necessary to add defoamers to eliminate the excess air bubbles during the mixing, placing, and consolidation of concrete [8].…”