Synthesis of Pure Dicalcium Silicate Powder by the Pechini Method and Characterization of Hydrated Cement

Abstract

Calcium silicate (CS) is a main component of Portland cement and is responsible for the strength development. Recent research has shown that dicalcium silicate cement (CSC) is bioactive and is a potential candidate for bone replacement. Traditionally, dicalcium silicate powder is synthesized by a solid state reaction or a sol-gel method. The solid-state reaction, however, usually needs a higher temperature and a longer calcination time. Furthermore, the dicalcium silicate powder made by the sol-gel method is not pure, and contains a significant quantity of CaO which is harmful to the strength and biological properties of the CSC. The Pechini technique is an alternative, low temperature polymeric precursor route for synthesis of high purity powders. In this study, purer CS powder was synthesized via the Pechini method by calcination at 800°C for 3h. DSC-TGA, XRD, SEM were used for characterization of CS powder and the hydrated cement. The DSC-TGA curves showed that the main exothermic peak was at 479°C and the total mass loss was 79.2%. The XRD patterns of CSC after hydration for 7, 14, and 35 days illustrated that dicalcium silicate hydrate (Ca1.5SiO3.5·xH2O, C-S-H) was formed in the hardened CS paste. The XRD peaks on the diffraction pattern of the C-S-H of the day 35 sample were of greater intensity than those at day 7 and day 14. This demonstrates that the hydration speed was slow and complete hydration could take more than one month. Flake-like crystals were observed on scanning electron micrographs following hardening. The degradation study result showed that there was no mass loss of CSC after the samples were soaked into phosphate buffered saline (PBS) for 40 days. The silicon assay revealed that orthosilicic acid could be released from CSC after the samples were soaked in simulated body fluid (SBF). Silicon is known to be critical to skeletal mineralization. The existence of silicon may stimulate the proliferation of bone and activate cells to produce bone. Investigation of cell attachment confirmed that the MC-3T3 cells attached well to the surfaces of CSC after seeding.

Calcium silicate/calcium aluminate composite biocement for bone restorative application: synthesis, characterisation andin vitrobiocompatibility

“…It indicates that the MC3T3 cells spread and proliferate better on 7S3A than on 3S7A, which can be attributed to the more content of Si in 7S3A. Previous studies 12,28 have reported that Si can be released from CSC prepared using pure β-Ca 2 SiO 4 . Figure 7 shows the silicon release results of 3S7A and 7S3A cement.…”

“…The concentrations of the released silicon were calculated by using the same calibration curve that was reported in our previous work. 12…”

“…[9][10][11] Previous study have shown that orthosilicic acid can be released from CSC during immersion in simulated body fluid (SBF). 12 Orthosilicic acid, may then stimulate collagen type I synthesis and osteoblastic differentiation in human osteoblast-like cells. 13 Silicon has been demonstrated by a number of researchers to be very important in the formation of mechanically robust mineralised tissues.…”

Conversion of Biowaste into Larnite by Sol‐Gel Combustion Route for Biomedical Applications

“…Recent literatures revealed that larnite was prepared by sol‐gel method, [17] solid state route, [18] Pechini method [19] at higher temperatures. Previous findings divulged that sol‐gel combustion method assisted in synthesizing pure larnite at 900 °C using citric acid as fuel [15] .…”

“…The calcium content in the larnite was found to be twice as compared to wollastonite which could induce faster apatite deposition better than wollastonite when exposed to the physiological environment. [15,17] Recent literatures revealed that larnite was prepared by solgel method, [17] solid state route, [18] Pechini method [19] at higher temperatures. Previous findings divulged that sol-gel combustion method assisted in synthesizing pure larnite at 900 °C using citric acid as fuel.…”