ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Low-cost synthesis of high-performance polycarboxylic ether by Co²⁺-, Ni²⁺- and Zn²⁺-catalyzed H₂O₂-NaHSO₃ initiation system

Heng Tong Zhang, Quan Xiang Feng, Cai Lin Liu, Xian Yan Ren, Hai Jun Yang, and Shu Dong Lin

State Key Laboratory for Environmental-Friendly Energy Materials, School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang, China

E-mail: liucailin2013@163.com

Received: 14 December 2020  Accepted: 19 February 2021

Abstract:

As a new type of high-performance water-reducing agent, polycarboxylate ether (PCE) has excellent properties such as small dosage and high water reduction rate. However, it is still necessary to develop a synthetic process to improve the performance of PCE at a low cost. In this paper, Co²⁺-, Ni²⁺- or Zn²⁺-catalyzed H₂O₂-NaHSO₃ redox initiation system is designed as a new cost-effective composite initiator system to synthesize PCE(Co²⁺), PCE(Ni²⁺) and PCE(Zn²⁺). The synthesized PCEs were characterized by FTIR, GPC, Zeta potential, XRD, TG, SEM and HPLC. Compared with PCE0 synthesized by H₂O₂-NaHSO₃ system without metal ion catalyst, FTIR and GPC data show that the molecular weights of PCE(Co²⁺), PCE(Ni²⁺) and PCE(Zn²⁺) were slightly reduced without any functional group type changed. When the double bond retention rate of isopentenol polyoxyethylene ether (TPEG) is 94.34%, the conversion rate of TPEG catalyzed by Co²⁺, Ni²⁺ or Zn²⁺ is up to 93.82%, which is much higher than 77.34% of PCE0. Compared with PCE0, PCE(Co²⁺), PCE(Ni²⁺) and PCE(Zn²⁺) have better dispersion and retention abilities, a 51-mm larger fluidity and a bigger early hydration rate of cement slurries. Interestingly, the water reduction rates of PCE(Co²⁺), PCE(Ni²⁺) and PCE(Zn²⁺) are 13.7%-25.3% higher than that of PCE0.

Keywords: Polycarboxylate ether; Synthesis; Redox radical polymerization; Catalysis

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-021-01573-3

Chemical Papers 75 (7) 3421–3428 (2021)