H and ¹³C NMR Spectra of a Hyperbranched Aromatic Polyamide from p-Phenylenediamine and Trimesic Acid

Abstract

The structure of hyperbranched aromatic polyamides synthesized from different ratios of p-phenylenediamine and trimesic acid (A2 + B3 reagent pair) has been investigated by means of 1 H and 13 C NMR spectroscopy. On the basis of a detailed NMR signal assignment six 1,3,5-trisubstituted benzene moieties with different substitution patterns can be distinguished. The different monomer ratios influence the polymer architecture with respect to the content of these substructures, the degree of branching and the predominant functionalities (COOH or NH2). An excess of B3 results in a larger number of branches and a predominant COOH functionalization. 1 H NMR proves site-specific interactions between lithium cations and the polymer substructures. The observed chemical shift effects simplify the quantification of the spectra. Finally, acetylation of amino groups by acetic acid, an impurity in commercial trimesic acid, could be proven.

Degree of Branching in Hyperbranched Poly(glycerol-co-diacid)s Synthesized in Toluene

“…hyperbranched polymer systems because, unlike the equation introduced by Hawker [25] and modified by Kim [26], it is valid for both low and high molecular weight hyperbranched polymers and oligomers. It is also more reliable when monomer feed compositions are varied [6] such as in the experiments reported here.…”

“…Deuterated NMR solvent, dimethylsulfoxide-d 6 , was ordered from Cambridge Isotope Laboratories (Andover, MA, USA). HPLC grades of acetone, chloroform, and methanol were purchased from J.T.…”

“…glycerol, in the presence of lipase and chemical catalysts to form hyperbranched polymers [1][2][3][4][5][6][7]. Understanding the relationship between D.B% and the physical and chemical properties of hyperbranched polymers is necessary to identify potential applications.…”

“…There are no unreacted functional groups or linear units along the branched chains of dendrimers. Conversely, hyperbranched polymers are prepared by one-pot processes whereby difunctional (A 2 ) and trifunctional (B 3 ) monomers are reacted at random yielding products with 15-90% branching [6,[11][12][13][14].…”

Modeling and Control of State-Affine Probabilistic Systems for Atomic-Scale Dynamics

“…In order years to integrate molecular simulations with dynamic to address this issue, a previous study by Oguz and Galanalysis and optimization. One approach is the derivalivan [17] proposed the use of high-dimensional step-step tion of stochastic time evolution equations from the correlation functions, which provided a more detailed probabilistic master equation [11], under assumptions state description of the film surface, compared to the that are mostly applicable for well-mixed reacting syssurface roughness alone. This study demonstrated the tems.…”