The Mechanical Performance and Reaction Mechanism of Slag-Based Organic-Inorganic Composite Geopolymers

Xiaotong Xing; Weiting Xu; Guihua Zhang; Xilian Wen

doi:10.3390/ma17030734

The Mechanical Performance and Reaction Mechanism of Slag-Based Organic-Inorganic Composite Geopolymers

Materials (Basel). 2024 Feb 3;17(3):734. doi: 10.3390/ma17030734.

Authors

Xiaotong Xing¹, Weiting Xu¹, Guihua Zhang¹, Xilian Wen²

Affiliations

¹ School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, China.
² Guangzhou Residential Construction Development Co., Ltd., Guangzhou 510075, China.

Abstract

A series of organic-inorganic composite geopolymer paste samples were prepared with slag-based geopolymer and three types of hydrophilic organic polymers, i.e., PVA, PAA, and CPAM, by ordinary molding and pressure-mixing processes. The reaction mechanism between slag-based geopolymer and organic polymers was studied by FT-IR, NMR, and SEM techniques. The experimental results showed that the slag-based geopolymer with the addition of 3% PVA presented the highest 28-day flexural strength of 19.0 MPa by means of a pressure-mixing process and drying curing conditions (80 °C, 24 h) compared with the geopolymers incorporating PAA and CPAM. A more homogeneous dispersion morphology was also observed by BSE and SEM for the 3% PVA-incorporated slag-based geopolymer. The FT-IR testing results confirmed the formation of a C-O-Si (Al) bond between PVA and the slag-based geopolymer. The deconvolution of the Q³ and Q²(1Al) species obtained by ²⁹Si NMR testing manifested the addition of PVA and increased the length of the silicon backbone chain in the geopolymer. These findings confirmed that a composite geopolymer with high toughness can be produced based on the interpenetrating network structure formed between organic polymers and inorganic geopolymer.

Keywords: mechanical performance; organic–inorganic composite geopolymer; pressure-mixing process; reaction mechanism; slag-based geopolymer.

Grants and funding

This research was funded by National Natural Science Foundation of China, grant number 52178208; the Fundamental Research Funds for the Central Universities, grant number 2023ZYGXZR031; the Natural Science Foundation of Guangdong, China, grant number 2021A1515010613; and the Science and Technology Program of Guangzhou, China, grant number 202201010738.