Rashmi Singla, T. Mishra, T. C. Alex, Sanjay Kumar
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引用次数: 0
Abstract
In order to overcome the brittle behavior of conventional geopolymers, of late, a paradigm shift towards development of hybrid geopolymers has commenced. This study describes hybrids synthesized by co-milling metakaolin and solid organics (epoxy resin: diglycidyl ether of bisphenol A and hardener: dicyandiamide) followed by alkali activation. The developed hybrid geopolymers exhibit enhanced mechanical and physical properties. Physical and mechanical properties of such hybrids depend on the extent of molecular-level interactions and microstructural evolution during geopolymerisation. Evolution of molecular structure from precursor stage (co-milled samples) to hybrid geopolymers is studied using transmission electron microscopy (TEM) and 27Al, 13C, 29Si solid-state nuclear magnetic resonance (NMR) spectroscopy. NMR and TEM analyses of the hybrid geopolymers illustrate the formation of Si–O–C bonds and uniform C distribution (with no phase separation); this confirms inorganic–organic chemical interactions during geopolymerisation. Detailed assessment of pore characteristics using TEM, mercury intrusion porosimeter, and Brunauer–Emmett–Teller reveal formation of a dense gel (with reduced pore size and pore volume) in hybrid geopolymer vis-à-vis MK-based inorganic geopolymer. The implication of such microstructural features on mechanical and physical properties is discussed. Lastly, the suitability of developed hybrids as fire-retardant materials used in mass transit applications is highlighted.
期刊介绍:
Materials and Structures, the flagship publication of the International Union of Laboratories and Experts in Construction Materials, Systems and Structures (RILEM), provides a unique international and interdisciplinary forum for new research findings on the performance of construction materials. A leader in cutting-edge research, the journal is dedicated to the publication of high quality papers examining the fundamental properties of building materials, their characterization and processing techniques, modeling, standardization of test methods, and the application of research results in building and civil engineering. Materials and Structures also publishes comprehensive reports prepared by the RILEM’s technical committees.