Facile Synthesis of Ferrocene-Based Polyamides and Their Organic Analogues Terpolyamides: Influence of Aliphatic and Aromatic Sequences on Physico-Chemical Characteristics

Abstract

Efforts have been devoted to synthesize and characterize processable polymers with desired properties.Herein, four different series of aromatic and aliphatic terpolyamides were prepared via solution phase polycondensation of 4,4'-oxydianiline and hexamethylenediamine (HMDA) with various diacids chlorides (isophthalyol dichloride, terepthalyol dichloride, 1, 1'-ferrocene dicarboxylic acid chloride and transazobenzene-4, 4'-dicarbonyl chloride). The structural, morphological and physico-chemical nature of as prepared polymers was explored by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermal analysis (TGA and DSC), and wide-angle x-ray diffraction (WAXRD). Moreover, an aliphatic diamine was incorporated in varying concentration as a exible methylene spacer and the effect of its concentration on the properties of polyamides was also studied. Changes in various physicochemical properties such as solubility, inherent viscosity, surface morphology and ame retarding behaviour were investigated. Marked difference in morphology and solubility was observed with the change in the ratio of segments in the chain. Inherent viscosities of polymers ranged from 1.8052-1.6274 dl/g indicating reasonably moderate molecular weights. Interestingly, ferrocene based aromatic polymers were more thermally stable (T g 260 o C, T i 310 o C, T h 525 o C, T f 720 o C, for PF 0 ), and also found to exhibit best ame retarding behavior (limiting oxygen index (LOI) value for PF 0 is LOI 33.15 %).

Ferrocene-Based Terpolyamides and Their PDMS-Containing Block Copolymers: Synthesis and Physical Properties

“…The FTIR spectra of the organic analogs are displayed in Figure S2A,B . The FTIR spectra depict the occurrence of the polycondensation for the synthesis of terpolyamides by the presence of strong, characteristic stretching vibration bands for the amide group in the ranges of 3350–3270 cm −1 (N-H stretch), 1668–1633 cm −1 (amide carbonyl), and 1600–1540 cm −1 (N-H deformation) that is according with the reported literature [ 17 ]. The stretching bands of weak intensities were observed in the range of 3000–2900 cm −1 for the aliphatic sp 3 -CH moieties.…”

“…The PDMS-containing block copolymers showed diffused morphology that can be attributed to the movement of siloxane moiety toward the surface of the material as reported earlier [ 31 , 38 ]. The siloxane moiety can become a dominant part of the surface and, due to this unique feature of siloxane, these materials can also be used as surface modifiers [ 17 , 18 , 41 ].…”

“…The organometallic polyamides possessing a metal center in the polymer backbone are under consideration for the unique combination of properties offered by inorganic and organic centers in the polymer backbone [ 15 ]. Ferrocene is an organometallic compound that has been widely used in many approaches to utilize its good redox behavior, thermal, photo, air, water, and oxidative stability [ 16 , 17 , 18 ]. Due to the excellent properties of ferrocene moiety, it has been incorporated in the main chain or as a pendant group in the polymer backbone for a variety of applications such as electrical devices, photo-resistive semiconductors, ion sensing, energy storage devices, thermal and moisture resistant coatings, flame-retardant materials, etc.…”

“…[ 19 , 20 , 21 , 22 , 23 ]. A combination of ferrocene moiety with flexible linkages in the backbone of polyamides has been widely used as a strategy to improve their processability along with their improved physiochemical properties [ 17 , 18 ].…”

“…Polyamides have been made processable via terpolymerization or copolymerization processes in several approaches [ 17 ]. A terpolymer is a polymer comprising three different monomers, incorporating the properties of each monomer, while a copolymer consists of more than one repeating unit of different types of monomers in the polymer chain.…”