Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
Browse
3 results
Search Results
Now showing 1 - 3 of 3
Article Citation - WoS: 5Citation - Scopus: 5Stabilization of Calcareous Subgrade Soils With Polyelectrolytes: Mechanisms and Mechanical Properties(Taylor & Francis, 2023) Huang, Jianxin; Kogbara, Reginald; Mohomad, Yosef; Kogbara, Reginald B.; Masad, Eyad; Sukhishvili, Svetlana; Little, DallasOrganic polyelectrolytes, i.e. anionic poly(sodium 4-styrenesulphonate) (PSS), cationic poly(diallyldimethylammonium chloride) (PDADMAC) and their polyelectrolyte complexes (PECs) were evaluated for stabilisation of calcareous sandy subgrade soil. This paper investigated the effects of polymer type, surface charge type of PEC, concentrations of PEC solutions and dosages of polymer solutions added to the soil on improvement of soil mechanical properties. We found that anionic polymers, for both PECs and individual polyelectrolytes, were superior to their cationic counterparts in improving soil strength. Besides, the constituent polyelectrolytes, PSS and PDADMAC, worked better than their PECs for the specific soil investigated. The strength of polymer-treated soils was also found to increase with the increase in dosages of the polymer solutions as well as curing periods. Furthermore, polymer-treated soil specimens exhibited significant toughness improvement, which was higher than cement-treated samples. Scanning electron microscopy images revealed the abundance of long palygorskite fibres covering the surfaces of larger calcite and dolomite particles and linking surrounding aggregates after adding polymers. This observation suggests the interconnection of palygorskite fibres and their linking networks between and among coarse aggregates as the likely mechanism of polymer stabilisation of the soil studied.Article Citation - WoS: 14Citation - Scopus: 20Design of Polymeric Antiscalants Based on Functional Vinyl Monomers for (fe, Mg) Silicates(American Chemical Society, 2017) Topçu, Gökhan; Çelik, Aslı; Baba, Alper; Demir, Mustafa MuammerSilica/silicate scaling is one of a few detrimental problems that cause high economical loss in the geothermal and petroleum fields. The prevention of silica/silicate has been attempted using antiscalants with functional groups, particularly -NH2; however, metal silicates are commonly found in the fields, and the antiscalants developed thus far are not effective against these compounds. In this work, polymeric antiscalants have been developed by merging two or more functional comonomers consisting of various chelating groups for metal cations. Homo- and copolymers of acrylamide (AM), the sodium salt of vinyl sulfonic acid (VSA), and vinyl phosphonic acid (VPA) were synthesized to examine their antiscaling performance against metal silicate scaling. Lab-scale metal silicates were obtained in a pressured autoclave reactor. The antiscalants were tested at various dosages (25, 50, and 100 ppm), and their effects were investigated from the leftover decantates after isolation of the solid precipitates. The polymeric antiscalants were found to be particularly effective against metal silicates and ineffective against simple silica precipitates. Acidic groups may be coordinating the metal cations, which prevents the formation of precipitates. Among these acidic comonomers, VSA-containing polymers, in particular, increased the solubility of metal silicates.Article Citation - WoS: 2Citation - Scopus: 3Preparation and Characterization of Diphasic Sol-Gel Derived Unsupported Mullite Membranes(Springer Verlag, 2011) Topuz, Berna; Çiftçioglu, MuhsinDiphasic gels prepared by mixing freshly prepared polymeric silica and polymeric boehmite sols through a modified Al-alkoxide route in mullite compositions led to the crystallization of mullite upon heat treatment at 775°C. Mullite formation was observed at a 100°C higher temperature when diphasic gels were formed by mixing aged polymeric sols containing about 2 nm in diameter boehmite species. These relatively low mullite formation temperatures were attributed to the nanoscale sizes of the polymeric species of the two amorphous phases present in the diphasic gels.