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

Abstract

Poly(vinyl butyral) (PVB) boasts a wide array of applications, but its synthesis suffers from contamination of residuals and high energy and water consumption. This study pioneers that chaotropic agents can serve as effective dispersants for producing a uniform particle size distribution and high-purity PVB in aqueous media at room temperatures (e.g., 27 °C). We demonstrate that using chaotropic agents as dispersants offers notable advantages in facile synthesis conditions, energy conservation, and ease of purification while simultaneously upholding a high acetalization degree as well as a uniform particle size distribution. This combination of heightened purity and even dispersion confers a suite of superior properties, including adhesion, solubility, thermal stability, and optical clarity, well suited for practical applications. Mechanistic insights suggest that chaotropes contribute to enhance the conformational extension of PVA and PVB chains and thus accelerate the acetalization kinetics, ultimately leading to elevated rigidity for the resultant PVB granule surfaces. This, in turn, further augments the rigidity of PVB granules to impede their coalescence. This finding offers a valuable complementary strategy for PVB synthesis and deserves exploration in massive production.