Title: A Novel Polycarboxylate Superplasticizer Using Polyvinyl Alcohol as Side Chains: Design, Synthesis and Characterization

Author(s): Xiao Liu, Qifeng Luo, Ziming Wang, Chunlei Xia, Ming Zhao, Wu Zhou, Mi Zhou, Jianan Guan

Publication: Symposium Paper

Volume: 354

Issue:

Appears on pages(s): 125-142

Keywords: polycarboxylate superplasticizer; molecular design; polyvinyl alcohol; fluidity retention; hydration kinetics

DOI: 10.14359/51736067

Date: 7/1/2022

Abstract:
It is well-known that the synthesis of comb-like polycarboxylate superplasticizer (PCE) strongly relies on polyethylene glycol (PEG) macromonomer as side chains to provide good dispersibility. However, ethylene oxide (EO), the main source of PEG, has many disadvantages such as flammability and explosiveness, harsh synthesis conditions, high equipment requirements, and high risk of impact on PCE even concrete industry, etc. Therefore, it is urgently necessary to develop a novel PCE by other substitutes, achieving innovative chemistry of PCE. In this study, polyvinyl alcohol (PVA), which synthesis does not depend on EO, was originally designed as side chains instead of PEG. A comb-like superplasticizer, i.e. PAA-g-PVA, was successfully synthesized by “graft from” copolymerization using butyl acrylate (BA) as main chain monomer and vinyl acetate (VAc) as side chain monomer. Compared with conventional PCE, PAA-g-PVA exhibited better fluidity retention of cement paste, as it can maintain a higher adsorption amount on cement particles. The hydration kinetics and Krstulovic-Dabic (K-D) model showed PAA-g- PVA less retarded the hydration process and rapidly promoted the hydration into the diffusion-controlled period. The aim of this study is to introduce a novel polymer with potential engineering applications and good performance, which can be used as an alternative to PCE.