Preparation and characterization of 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin grafted on organosilane-pillared montm
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ORIGINAL RESEARCH
Preparation and characterization of 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin grafted on organosilane-pillared montmorillonite by covalent bonding Weikang Li 1 & Fengyang Zhao 1 & Baocan Zhu 1 & Xia Kong 1 & Xixi Zhu 1 & Qingyun Liu 1 Received: 4 August 2020 / Revised: 10 September 2020 / Accepted: 18 September 2020 # Springer Nature Switzerland AG 2020
Abstract Montmorillonite (MMT)-based composites are usually prepared by the absorption method, which results in the unstable MMT composites, because adsorbates are easy to drop down from MMT. In this work, 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (H2TCPP) molecules were grafted on interfaces of (3-aminopropyl)triethoxysilane (APTES)-pillared MMT by dehydration condensation reaction. X-ray diffraction (XRD) revealed that the interlayer space of the MMT was enlarged from 16.24 to 22.21 Å by introduction of APTES. Fourier-transform infrared (FT-IR) data verified the covalent bonding between APTES-pillared MMT and H2TCPP molecules. UV-Vis absorption spectra displayed that the Soret band of H2TCPP molecules in H2TCPP/APTES/MMT composites had a red-shift with 17 nm compared with that of the monomers, revealing that H2TCPP molecules assembled into J-aggregates. Moreover, H2TCPP/APTES/ MMT composites were characterized by thermogravimetric analysis (TGA) and fluorescent spectrophotometer. The APTES-pillared MMT modified with porphyrin has a potential application in biomedicine and environment. Keywords Porphyrin . Organosilane pillared . Montmorillonite . Composite
1 Introduction Montmorillonite (MMT) is a kind of natural lamellar silicate mineral with negative charge on the surface. On account of the electrostatic interaction between sheet layers, it piled into clay. The crystal cell in its crystal structure is composed of two layers of silicon-oxygen tetrahedrons sandwiched by one layer of aluminum-oxygen octahedrons [1]. MMT has a strong adsorption capacity and cationic exchange performance, so it is widely used as an adsorbent of toxic substances [2], fire retardant [3], catalyst [4], drug carrier [5], and good supports for polymer-layered nanocomposites [6]. Nevertheless, raw MMT has many defects. For example, it is hard to combine organic functional materials with MMT, due to the absence of functional groups of MMT. Thus, * Xia Kong [email protected] * Xixi Zhu [email protected] * Qingyun Liu [email protected] 1
College of Chemical and Environmental Engineering, Shandong University of Science and Technology, Qingdao, China
raw MMT is modified with organic molecules only by a physical adsorption, which resulting in the unstable MMT-based composites, because adsorbates are easy to fall off from interlayers of MMT. To broaden the practical application of MMT, it is necessary to functionalize it. Scientists have employed some organic molecules to modify MMT to endow some performances. For example, chitosan was selected to modify MMT to make nacre-like bionanocomposite films with superior mechanical properties, light transmittance,
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