Toward a Delaminated Organotalc: The Use of Polyamidoamine Dendrons

Abstract

A sequence of generations of the polyamideamine dendron, PAMAM-talc-Gn (n = 1-7), was constructed on the surfaces of ethylenediaminepropyl-functionalized magnesium phyllosilicate lamellas by using a modified microwave-assisted synthesis. The successful functionalization of the inorganic layers by the organic dendrimer was confirmed by FTIR and (13)C NMR spectroscopies, elemental analyses, and thermogravimetric analysis (TGA). The solid materials presented an increase in their interlamellar space and disorganization of lamella packing with the growth of the dendrons. Thermal-programmed desorption analysis showed that the lower dendron generation, PAMAM-talc-G1, adsorbed 1.30 mmol of CO2/g of sorbent at 30 °C. PAMAM-talc-G5 adsorbed the double of PAMAM-talc-G3, probably due to the higher amount of the primary amine group; however, PAMAM-talc-G5 adsorbed more CO2 than PAMAM-talc-G7 probably because in the delaminated seventh generation intradendron N-H interactions were more prevalent than in the fifth generation and blocked CO2 interaction sites.

Synthetic Talc and Talc‐Like Structures: Preparation, Features and Applications

“…showed that the delamination of organotalc could be achieved by a simple ultrasound treatment in water by creation of surface groups on lamella. Recently, Andrade et al . reported an increase up to 54 Å of the organotalc interlayer space by functionalization of the layers with dendrimers.…”

Quasi-solid electrolyte with polyamidoamine dendron modified-talc applied to dye-sensitized solar cells

“…The synthesis of the organotalcs were reported in our previous work [25]. Briefly, the first generation (PAMAM-talc-G1) was synthesized by mixing 1.0 g EDA-talc (as reported by Moura et al [11]), 4.0 mL methanol and 1.0 mL MA in an 80 mL all-polymer autoclave lined with Teflon ® and heated under microwave irradiation, at 40 W for 40 min.…”

“…When looking at the rate constants of the adducts (k 2 ) in Table 1, a tenfold increase in reaction rate can be seen in the higher generation dendron organotalcs (k 2 ¼ 0.42 g mol À1 h À1 in PAMAM-talc-G7) than the lower generation dendron organotalcs (k 2 ¼ 0.04 g mol À1 h À1 in PAMAM-talc-G1). In the higher dendron generations, the reaction is faster because a large amount of basic sites in the surface of the dendrons is available to interact with iodine [25], which interact, firstly, with the basic sites from the surface and then slowly diffuse to the core. There is a small difference between the reaction rate with PAMAMtalc-G5 and PAMAM-talc-G7.…”

“…There is a small difference between the reaction rate with PAMAMtalc-G5 and PAMAM-talc-G7. Although PAMAM-talc-G7 is already delaminated [25], it would be expected a larger amount of basic sites available to interact faster with iodine. However, in this material, the end groups are sufficiently flexible to bind back to the core of the molecule, becoming a denser structure.…”

“…To further improve the gelation and the charge transport in the solar cells, the organotalcs were functionalized with different PAMAM dendron generations. The preparation and characterization of the organotalcs functionalized with PAMAM dendron used here were reported in our previous work [25]. Chargetransfer complexes PAMAM-iodine were also investigated.…”