Polyvinyl butyral (PVB) 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 NaNO3 as an additive can prevent the oversizing
agglomeration to offer high-purity and finely sized PVB products.
NaNO3 functions as a removable and recyclable dispersant
to enable uniform acetalization of poly(vinyl alcohol) with n-butanal in acidic aqueous media at ambient temperatures.
The salting-in effect of NaNO3 diminishes the hydrophobic
interaction of n-butanal and polymers, improving
the media dispersion and preventing agglomeration runaway. In contrast
to conventional systems, the NaNO3-assisted synthesis at
ambient temperature offers multiple sustainable benefits, including
suppression on byproducts, energy conservation, reduction on emission,
and reusability of the postacetalization medium. This finding offers
a valuable complementary strategy for PVB synthesis and deserves exploration
in massive production.