NaNO 3 Dispersant Enables Sustainable Acetalization towards High-Purity Polyvinyl Butyral

Polyvinyl butyral boasts many applications, yet its synthesis often suffers from oversizing agglomeration, resulting in limited product purity, and thus large energy consumption and waste emission for purification. This study for the first time demonstrates that incorporating NaNO 3 as additive can prevent the oversizing agglomeration to offer high-purity and finely sized polyvinyl butyral product. NaNO 3 functions as a removable and recyclable dispersant to enable uniform acetalization of polyvinyl alcohol with n -butanal in acidic aqueous media at ambient temperatures. The salting-in effect of NaNO 3 diminishes the hydrophobic interaction of n -butanal and polymers, improving the media dispersion and preventing the agglomeration runaway. In contrast to conventional systems, the NaNO 3 -assisted synthesis at ambient temperature offers multiple benefits, including suppression on by-products, energy conservation, reduction on emission and reusability of the post-acetalization medium. This finding offers a valuable complementary strategy for PVB synthesis and deserves exploration in massive production.