Syntheses of polycarboxylate superplasticizers: Microwave induction versus conventional thermal induction

Abstract

An eco-friendly and high-efficient preparation approach to synthesizing polycarboxylate superplasticizers (PCE) co-polymers based on microwave induction was described. Meanwhile, a series of detailed comparative studies about the effects of microwave induction and conventional thermal inductions on the conversion rate and reactivity ratio in the polymerization reaction, molecular structure, adsorption behavior and fluidizing effect of PCE co-polymers were reported. The results revealed that the green advances of PCE co-polymer preparation by microwave induction in the preparation time and conversion rate compared to conventional thermal induction. At lower dosage, the PCE co-polymer synthesized by microwave induction also has excellent dispersibility in the fresh cement paste (fcp). Furthermore, under microwave induction, relative reactivity of macromonomer (α-methallyl-ω-hydroxy poly (ethylene glycol) ether (HPEG)) is increased in polymerization system, and the monomers ratio of the co-polymers closer to feeding ratio is achieved.