Advanced high and low field 1H and 129Xe NMR methods for studying polymerization, curing and pore structures of geopolymers
Thesis event information
Date and time of the thesis defence
Place of the thesis defence
L10 hall
Topic of the dissertation
Advanced high and low field 1H and 129Xe NMR methods for studying polymerization, curing and pore structures of geopolymers
Doctoral candidate
Master of organic chemistry Jing Li
Faculty and unit
University of Oulu Graduate School, Faculty of Technology, Fibre and Particle Engineering Research Unit; NMR Research Unit
Subject of study
Process and Environmental Enginnering
Opponent
Professor Jean-Baptiste d’ESPINOSE de LACAILLERIE, Superior School of Physics and Industrial Chemistry of the City of Paris
Custos
Associate professor Päivö Kinnunen, University of Oulu
Advanced high and low field 1H and 129Xe NMR methods for studying polymerization, curing and pore structures of geopolymers
Geopolymers are three-dimensional aluminosilicate frameworks, synthesized from the aluminosilicate sources activated by alkali solutions under mild conditions. They are widely regarded as sustainable construction materials.
The understanding of geopolymer pore structures is important for their development. The mechanical properties of geopolymers dependent on their pore structures. Currently, the pore structures are often studied using destructive methods, which do not allow longitudinal studies. New methods are needed to characterize the time dependent properties of geopolymers.
In this thesis, advanced 1H and 129Xe NMR methods were applied to study the polymerization, curing and pore structure of geopolymers in this thesis: 1H relaxometry, 1H cryoporometry, 129Xe spectroscopy and 129Xe relaxometry. Several interconnected mesopores with different pore sizes were found.
Three factors were found to affect the geopolymerization and pore structures: water to solid ratio (w/s), silicon to aluminum ratio (Si/Al), and NH4OH post-treatment. High w/s favors large pore sizes and enhanced pore connectivity. Low Si/Al = 1 contributes to the formation of the zeolite phase, resulting from the formation of a gel phase with low Si/Al during geopolymerization. The NH4OH post-treatment did not change pore sizes but increased the level of pore connectivity.
The understanding of geopolymer pore structures is important for their development. The mechanical properties of geopolymers dependent on their pore structures. Currently, the pore structures are often studied using destructive methods, which do not allow longitudinal studies. New methods are needed to characterize the time dependent properties of geopolymers.
In this thesis, advanced 1H and 129Xe NMR methods were applied to study the polymerization, curing and pore structure of geopolymers in this thesis: 1H relaxometry, 1H cryoporometry, 129Xe spectroscopy and 129Xe relaxometry. Several interconnected mesopores with different pore sizes were found.
Three factors were found to affect the geopolymerization and pore structures: water to solid ratio (w/s), silicon to aluminum ratio (Si/Al), and NH4OH post-treatment. High w/s favors large pore sizes and enhanced pore connectivity. Low Si/Al = 1 contributes to the formation of the zeolite phase, resulting from the formation of a gel phase with low Si/Al during geopolymerization. The NH4OH post-treatment did not change pore sizes but increased the level of pore connectivity.
Last updated: 23.1.2024