H, ¹³C, and ³¹P NMR Study on Poly(vinylphosphonic acid) and Its Dimethyl Ester

Abstract

The microstructure of poly(vinylphosphonic acid) (PVPA) and poly(vinyl dimethyl phosphonate) (PVDMP) prepared by free radical polymerization was studied by a combination of one- and two-dimensional NMR spectra. Whereas 13C and 31P NMR spectra give less stereochemical information a signal split into diad, triad, and, at best, m-centered tetrad sequences for the methylene protons of PDMVP could be observed in the 1H NMR spectra. For PVPA our assignments differ from those previously published in the literature. The spectra of both polymers were complicated by the presence of head-to-head regioirregular structures with up to ∼17% for PVPA. For the regioregular part a mainly atactic structure was determined for PVPA, whereas PVDMP has an increased content of isotactic sequences. The dependency of 1H and 31P signals of PVPA on the degree of neutralization is presented.

Poly(vinyl phosphonic acid): Hydrodynamic Properties and SEC‐Calibration in Aqueous Solution

“…polymerization of Npa. [1,3,4] R g and R h values are of similar magnitude as observed for pure PAA-sodium salt solutions. [21] The r-parameter (the ratio r ¼ R G /R h ) varies from 1.8 to 2.6 for the PVPA samples.…”

Vinylphosphonic Acid Homo‐ and Block Copolymers

“…Since the 1 H 1 H COSY spectra display only one cross-peak among the peaks at about 2.1 and 1.5 ppm, respectively, they can be attributed to methylene protons in the meso diad, while methylene protons of the racemic diad resonate at %1.8 ppm. [30] In contrast, the 1 H 1 H TOCSY NMR (due to the used mixing time of 80 ms) is rather sensitive to long-range couplings, and thus, reveals cross-peaks among the distinct methin and methylene protons within the polymer backbone ( Figure 5).…”

“…Based on 13 C DEPT-135 spectra, the former peaks are identified as methine carbons, while the second group of peaks reflects the various methylene carbons. [30] A 13 C NMR spectrum of PVPA previously obtained via free radical polymerization is given for comparison ( Figure 6); note the less-resolved lineshape. In fact, the 1 H 13 C HSQC spectrum (e.g., of sample PVPA 91 ) that correlates carbons with directly bonded protons, indicates a distribution of methylene carbons that correlate with protons at about 1.5 and 2.1 ppm (m-diad), respectively, as well as with protons at 1.8 ppm (r-diad) (Figure 7).…”

“…A rather irregular chain structure has been proven. [30] The question, to what extend molecular weight and chain tacticity influences the association of the phosphonic acid groups via hydrogen bonds, the anhydride formation at elevated temperature and the proton transport in the dry and hydrated state, may only be answered with a PVPA with well defined molecular weight, narrow polydispersity and with a tuneable chain structure. Also, the availability of well-defined block copolymers with PVPA as hydrophilic block, would be very promising in view of phase separated materials for membrane applications.…”

Surface polyion complex gel with poly(vinylphosphonic acid) and poly(N-vinylamide)s

“…[1][2][3] It is possible to introduce a large amount of phosphonic acid into the main polymer chain due to the simple structure of VPA, in which the vinyl group is directly connected to the phosphorous atom. The electrostatic properties of poly(vinylphosphonic acid) (PVPA) have been investigated, such as the metal ion binding capability 4 and its acidity.…”