Effect of nano-ZnO on mechanical and thermal properties of geopolymer

Abstract

In this experimental study, we synthesized geopolymer materials with different amounts of nano-ZnO (0.3%, 0.5% and 0.7%). The effects of the nano-ZnO concentration on the mechanical, structural and thermal properties were studied in detail. XRD investigation revealed the formation of a glassy phase in all the samples and a small shift of the intense peak, which confirmed the incorporation of nano-ZnO into the geopolymer matrix. FTIR analyses showed an increase in the geopolymerization after the addition of nano-ZnO to geopolymer paste. The morphology of the inorganic polymers was studied by mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). The addition of nano-ZnO improved the ultrasonic pulse velocity and increased the compressive strength from 30 to 38 MPa. It was found that the strength reached its maximum value at a critical nano-ZnO concentration of 0.5 at.%. The thermal properties of geopolymer nano-ZnO were also investigated using thermogravimetric analysis (TGA), which showed that the incorporation of nano-ZnO decreased weight loss by the geopolymers. The density and the absorption water were also tested and all the results were discussed. ARTICLE HISTORY * The title of this manuscript should define any chemical symbols or structures by the names, so I suggest that authors change the title to "Study the effect of nano zinc oxide on structural, thermal, and mechanical properties of geopolymerbased metakaolin". "Study the effect of nano-ZnO on structural, mechanical and thermal properties of geopolymer-based metakaolin" → Effect of nano-ZnO on mechanical and thermal properties of geopolymer Abstract * Please, authors, clarify and rephrase the concept of the sentences in lines 20 and 21.Furthermore, infrared specters showed an increase of geopolymer gel content with the addition of nano-ZnO → FTIR analyses showed an increase in the geopolymerization after the addition of nano-ZnO to the geopolymer paste. * The sentences in the lines 25 and 26 need rephrasing and English grammar check, please.

Properties of Inorganic Polymers Based on Ground Waste Concrete Containing CuO and ZnO Nanoparticles

“…This may be attributed to the filling of the matrix voids. Similar observations have been reported in previous studies [ 22 , 44 ]. NPs may act as fillers in alkali-activated materials improving particle packing with reduced porosity and increased compressive strength.…”

“…Previous studies investigated the effect of different NPs on the mechanical properties of IPs. The incorporation of 0.5% ZnO NPs and 2% Al 2 O 3 NPs (of particle size of 60 nm and 300–500 nm) increased compressive strength of metakaolin-based IPs by 26% and 30%, respectively [ 44 , 54 ]. Metakaolin geopolymer CuO-NPs composites gained improved flexural strength [ 43 ].…”

“…A small shift to higher angles is observed when adding NPs. This can probably be attributed to an interaction with the freely dissolved species [ 44 ].…”

“…A small shift of the intense peak may confirm the incorporation of nano-ZnO into the geopolymer matrix. It is worth noting that there is neither evidence of CuO or ZnO Raman signatures nor new functional group after the incorporation of CuO/ZnO NPs, indicating that only a physical interaction occurred between NPs and IPs matrix [ 44 ].…”

“…The addition of nanosilver improved the mechanical strength, durability, and antibacterial properties of Ag-IPs composites [40][41][42]. Additionally, CuO and ZnO NPs can be included as reinforcement for IPs pastes [43,44] and also, generating antibacterial IPs surfaces [45,46]. Nanoparticles in inorganic polymer preparation is very limited.…”