Precise Characterization of the Sequence Distribution of Poly(vinyl butyral) (PVB) by 2D-NMR and Isotope Enrichment

Abstract

The complicated chemical structure of poly(vinyl butyral) (PVB) as well as its acetalization mechanism was unveiled by multidimensional NMR with the assistance of the 13 C labeling. The isotope enrichment significantly suppresses the NMR signal from the side groups, which enables us to precisely determine the sequence distribution of various monomers, i.e., vinyl butyral (VB) and vinyl alcohol (VA), along the PVB backbone. The primary, secondary, and tertiary carbons were directly identified by NMR spectral editing through 13 C distortionless enhancement by polarization transfer (DEPT) NMR experiments. Various 2D-NMR experiments, including COSY, NOESY, HMQC, and INADEQUATE, were adopted to establish homo-and heteronuclear coupling through either chemical bond or space correlation. Because only the PVB backbone is 13 C-enriched, all 1 H and 13 C NMR spectra provided unprecedented resolved information on various sequence information. In total, 13 13 C and 18 1 H resolved NMR peaks are assigned. Based on the accomplished 13 C NMR peak assignment and quantitative 13 C NMR of PVB with different acetalization degrees as well as numerical modeling, a possible acetalization reaction mechanism is proposed.

Engineering a polyvinyl butyral hydrogel as a thermochromic interlayer for energy-saving windows

“…The overall monomer sequence distribution should be an overall random blocky configuration. 55 We demonstrate that water would be a weak solvent for PVB with butyral groups of ∼30 mol%. Thus, water can sufficiently swell the segments with a high fraction of hydroxyl groups to warrant a local equilibrium state while inducing the dispersed aggregation of segments with a high fraction of butyral groups to give thermally distinct elasticity and plasticity.…”

“…1b). We reason that, as per several post-polymerization modification processes, 53–55 the positioning of the monomeric unit in the PVB chain is not entirely independent of the chemical nature of adjacent units. The overall monomer sequence distribution should be an overall random blocky configuration.…”

Chaotropic Salt Dispersion Enables Room-Temperature Synthesis of High-Purity Polyvinyl Butyral

“…Additionally, precise characterization of the synthesized PVB’s configuration and its comparison with conventional methods are required to unveil unique structural impacts beyond purity considerations . In the future, the establishment of a microkinetic model represents a promising avenue.…”

“…Additionally, precise characterization of the synthesized PVB's configuration and its comparison with conventional methods are required to unveil unique structural impacts beyond purity considerations. 49 In the future, the establishment of a microkinetic model represents a promising avenue. This model would facilitate the correlation of theoretical equations with the evolution of the AD or particle size, thereby enhancing our ability to systematically control the synthesis of PVB with greater precision and rationality.…”

Original synthesis of polyvinyl butyral with a green deep eutectic solvent and a weakly polyacrylic acid from polyvinyl alcohol and the impacts of the chains structures of polyvinyl alcohol

“…Using inorganic acids such as HCl, H 2 SO 4 , and H 3 PO 4 as catalysts [23][24][25] could have prompted acetal reaction due to their strong ability to dissociate hydrogen ions, but extreme accumulation of [H + ] was readily subjected to uneven acetalization, polymer agglomeration, and cross-linking, unfavourable to stable production. Wang [26,27] increased the AD of PVB resins up to 84.4% using p-toluenesulfonic acid as a catalyst, but the range of M n of the PVB was limited to 29,300-36,100 g Á mol À1 .…”