Solvent‐free polymerization of citric acid and hexamethylenediamine for novel carboxylated polyamides

Abstract

Copolymers of tributyl citrate (TBC) and hexamethylenediamine (HMDA) were synthesized with a solvent‐free condensation method with molar ratios of TBC to HMDA varying from 2:1 to 1:2. The reaction led to poly(succinimide‐co‐citramide) copolymers which were characterized by infrared and Raman spectroscopies, X‐ray diffraction, and thermal analyses. Hydrolysis of the copolymers resulted in water soluble polycitramides with number averaged molecular weights ranging from 1.16 × 104 to 5.00 × 103 as determined by gel permeation chromatography. 1H, 13C, and 13C‐1H‐heteronuclear single quantum coherence NMR spectroscopy has confirmed that the hydrolyzed polycitramides with COOH side chains and amide backbones are structurally similar to biodegradable poly(aspartic acid) (PASP). Interestingly, the polycitramides showed Ca2+ and Pb2+ ion chelating capabilities higher than PASP, citric acid–sorbitol copolymers, or conventional resins. Thus, the polycitramides offer promise as a totally new class of metal sequesters and renewable substitutes for PASP and poly(acrylic acid). © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Supramolecular self-assembly of a polyelectrolyte chain based on step-growth polymerization of hydrophobic and hydrophilic monomers

“…This reaction occurs by ring opening of the imide group through scission of either C-N bond. 32 FTIR spectrum of the hydrolyzed polymer (Fig. 1c) shows disappearance of the imide C]O band at 1702 cm À1 and appearance of bands due to the COO À group, when compared with Fig.…”

“…The bands at 1702 and 1781 cm À1 are attributed to asymmetric and symmetric C]O stretching vibrations of the cyclic imide group (Scheme 1), respectively. 32,35 This is conrmed by Raman spectroscopic analysis of the polymer. As shown in Fig.…”

“…[42][43][44] Table 1 shows the particles have very high chelating capabilities for metals such as Ca 2+ and Pb 2+ , very close to recently reported polycitramides. 32 Poly(aspartic acid) (PASP) polymers have chelating capacities of 54.0-65.0 mg g À1 for Ca 2+ ion, 45 while polyesters prepared from citric acid and D-sorbitol have even lower chelating capacities of 13-26 mg g À1 for Ca 2+ ion in a recent study. 46 Commercial chelating resins, e.g., Amberlite 200, Duolite GT-73, and Lewatit TP 207, have chelating capacities of 122-352 mg g À1 for Pb 2+ ion.…”

“…The metal ion chelating capabilities of the polycitramides were measured by using a Ca 2+ -and a Pb 2+ -selective electrode (Shanghai Precision & Scientic Instrument Co., Ltd.), respectively, and an ion meter (Shanghai Precision & Scientic Instrument Co., Ltd., Model PXB 720A) according to the procedures described in the previous study. 32 A sample (10.0 mg) was dissolved in 50 mL of a pH ¼ 7.0 aqueous solution, which had been adjusted to give a CaCl 2 concentration of 1.0 mmol L À1 (or a PbNO 3 concentration of 1.0 mmol L À1 ) and a potassium chloride concentration of 0.08 mol L À1 . The resulting mixture was stirred at 30 C for 10 min and the Ca 2+ ions (or Pb 2+ ions) in the solution were determined using the Ca 2+ ion electrode (or Pb 2+ ion electrode).…”

Carbonyldiimidazole‐accelerated efficient cure of epoxidized soybean oil with dicyandiamide

“…In the last few years, polymerization of bio‐based monomers has been widely investigated with the intention to replace petroleum‐derived chemicals with renewable raw materials. Successful examples include bio‐based polyamides, polyurethanes, polyesters, epoxy resins, polybenzoxazines, and phenolic resins . Vegetable oils are available in large quantities from various natural resources.…”