Geopolymer/PEG Hybrid Materials Synthesis and Investigation of the Polymer Influence on Microstructure and Mechanical Behavior

Geopolymers are aluminosilicate inorganic polymers, obtained from the alkali activation of powders containing SiO2+Al2O3>80wt%, mainly proposed as environmentally friendly building materials. In this work, metakaolin-based geopolymers have been prepared and a water-soluble polymer, polyethylene glycol (PEG), has been added in different percentages to obtain organic-inorganic hybrid geopolymers. The influence of both the polymer amount and aging time on the structure and the mechanical behavior of the materials were investigated. FTIR spectroscopy allowed us to follow the evolution of the aluminosilicate framework during the geopolymerization process. This analysis revealed that PEG leads to a network which is rich in Al-O-Si bonds and forms H-bonds with the inorganic phase. SEM microscope showed that the two phases are interpenetrated on micrometric scales. Traction and bending tests have been carried out on appropriate samples to investigate the mechanical behavior of the obtained hybrids, showing that both PEG content and aging time affect the material behavior

Synthesis and chemical characterization of new silica polyethylene glycol hybrid nanocomposite materials for controlled drug delivery

A series of inorganic organic hybrid nanocomposite materials, containing indomethacin (IND) as a model drug, were synthesized using an inorganic precursor (tetraethoxysilane, TEOS) and an organic precursor (polyethylene glycol, PEG 400) through sol-gel chemistry. The various synthesized hybrids differed in PEG weight percentage (0, 6, 12, 24, and 50% wt). On an equal PEG percentage, different amounts of the non-steroidal anti-inflammatory drug were loaded (5, 10, and 15% wt). The bonding characteristics of the various composites were investigated via FT-IR spectroscopy, which suggests the formation of H-bonds between hybrids components. X-ray diffraction (XRD), used for the investigation of their atomic organization, and scanning electron microscopy (SEM) analysis confirmed the amorphous and nanocomposite structure of synthesized materials, which appeared morphologically homogeneous. The in vitro bioactivity evaluation was carried out by analyzing the apatite layers produced on the hybrid materials using SBF as incubation medium. The apatite formation was analyzed using SEM coupled to energy-dispersive electron X-ray spectroscopy. The in vitro release of indomethacin from the new drug-loaded bioactive materials was investigated by HPLC-UV-ESIMS/MS analysis. Data obtained allowed us to state that the drug release was markedly affected by the PEG percentage in investigated hybrid materials.A series of inorganic organic hybrid nanocomposite materials, containing indomethacin (IND) as a model drug, were synthesized using an inorganic precursor (tetraethoxysilane, TEOS) and an organic precursor (polyethylene glycol, PEG 400) through sol-gel chemistry. The various synthesized hybrids differed in PEG weight percentage (0, 6, 12, 24, and 50% wt). On an equal PEG percentage, different amounts of the non-steroidal anti-inflammatory drug were loaded (5, 10, and 15% wt). The bonding characteristics of the various composites were investigated via FT-IR spectroscopy, which suggests the formation of H-bonds between hybrids components. X-ray diffraction (XRD), used for the investigation of their atomic organization, and scanning electron microscopy (SEM) analysis confirmed the amorphous and nanocomposite structure of synthesized materials, which appeared morphologically homogeneous. The in vitro bioactivity evaluation was carried out by analyzing the apatite layers produced on the hybrid materials using SBF as incubation medium. The apatite formation was analyzed using SEM coupled to energy-dispersive electron X-ray spectroscopy. The in vitro release of indomethacin from the new drug-loaded bioactive materials was investigated by HPLC-UV-ESIMS/MS analysis. Data obtained allowed us to state that the drug release was markedly affected by the PEG percentage in investigated hybrid materials

Characterization,bioactivity and ampicillin release kinetics of of TiO2 and TiO2-4SiO2 synthesized by sol-gel processing

Local drug delivery of antimicrobics by sustained release delivery system can be used to treat periodontal disease. Advantages of these systems may include maintaining high levels of antibiotic in the gingival crevicular fluid for a sustained period of time and ease of use with high patient acceptance. The materials used are TiO2 and TiO24SiO2, mixed with sodium ampicillin, a broad-spectrum antibiotic, have been synthesized by sol-gel method. The amorphous nature of the gels was ascertained by X-ray diffraction analysis. Release kinetics in a simulated body fluid (SBF) have been subsequently investigated. The amount of sodium ampicillin released has been detected by UV-VIS spectroscopy and SEM. The release kinetics seems to occur in more than one stage. HPLC analysis has also been taken to ensure the integrity of ampicillin after the synthetic treatment. Finally, SEM micrographs and EDS analysis showed the formation of a hydroxyapatite layer on the surface of the samples soaked in SBF. Both the materials showed good release and could be used as drug delivery bioactive systems. High antimicrobial effects of samples against Escherichia coliand Streptococcus mutants were foun

Entrapment of Acridine Orange in Metakaolin-Based Geopolymer: A Feasibility Study

Few studies have explored the immobilization of organic macromolecules within the geopolymer matrix, and some have found their chemical instability in the highly alkaline geopolymerization media. The present work reports on the feasibility of encapsulating the potentially toxic acridine orange (AO) dye in a metakaolin based geopolymer while maintaining its structural integrity. The proper structural, chemical, and mechanical stabilities of the final products were ascertained using Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric (TGA/DTG), and mechanical analyses, whereas the dye integrity and its stability inside the geopolymer were investigated by the UV-Vis analysis. In addition, the antimicrobial activity was investigated. The FT-IR and XRD analyses confirmed the geopolymerization occurrence, whereas the TGA/DTG and mechanical (compressive and flexural) strength revealed that the addition of 0.31% (AO mg/ sodium silicate L) of AO to the fresh paste did not affect the thermal stability and the mechanical properties (above 6 MPa in flexural strength and above 20 MPa for compressive strength) of the hardened product. UV-Vis spectroscopy revealed that the dye did not undergo chemical degradation nor was it released from the geopolymer matrix. The results reported herein provide a useful approach for the safe removal of toxic macromolecules by means of encapsulation within the geopolymer matrix

Entrapment of Acridine Orange in Metakaolin-Based Geopolymer: A Feasibility Study

settingsOrder Article Reprints Open AccessArticle Entrapment of Acridine Orange in Metakaolin-Based Geopolymer: A Feasibility Study by Antonio D’Angelo 1,2,Luigi Vertuccio 1,Cristina Leonelli 3ORCID,Mohammad I. M. Alzeer 4 andMichelina Catauro 1,*ORCID 1 Department of Engineering, University of Campania “Luigi Vanvitelli”, Via Roma n. 29, 81031 Aversa, Italy 2 Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, Via Vivaldi 43, 81100 Caserta, Italy 3 Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Via P. Vivarelli 10, 41125 Modena, Italy 4 Fibre and Particle Engineering Research Unit, University of Oulu, Pentti Kaiteran Katu 1, 90014 Oulu, Finland * Author to whom correspondence should be addressed. Polymers 2023, 15(3), 675; https://doi.org/10.3390/polym15030675 Received: 1 January 2023 / Revised: 19 January 2023 / Accepted: 25 January 2023 / Published: 28 January 2023 (This article belongs to the Special Issue Recent Developments in Geopolymer Composites) Download Browse Figures Versions Notes Abstract Few studies have explored the immobilization of organic macromolecules within the geopolymer matrix, and some have found their chemical instability in the highly alkaline geopolymerization media. The present work reports on the feasibility of encapsulating the potentially toxic acridine orange (AO) dye in a metakaolin based geopolymer while maintaining its structural integrity. The proper structural, chemical, and mechanical stabilities of the final products were ascertained using Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric (TGA/DTG), and mechanical analyses, whereas the dye integrity and its stability inside the geopolymer were investigated by the UV-Vis analysis. In addition, the antimicrobial activity was investigated. The FT-IR and XRD analyses confirmed the geopolymerization occurrence, whereas the TGA/DTG and mechanical (compressive and flexural) strength revealed that the addition of 0.31% (AO mg/ sodium silicate L) of AO to the fresh paste did not affect the thermal stability and the mechanical properties (above 6 MPa in flexural strength and above 20 MPa for compressive strength) of the hardened product. UV-Vis spectroscopy revealed that the dye did not undergo chemical degradation nor was it released from the geopolymer matrix. The results reported herein provide a useful approach for the safe removal of toxic macromolecules by means of encapsulation within the geopolymer matrix