Effect of macromolecular sodium polyacrylate on the molecular structure and properties of polyvinyl butyral synthesized deep eutectic solvent

Abstract

Sodium polyacrylate (PAAS), a macromolecule surfactant, was employed in the synthesis of polyvinyl butyral (PVB) using a deep eutectic solvent (DES) as the catalyst. Contrasting with traditional low molecular weight surfactants, scanning electron microscopy (SEM) analysis has confirmed that PAAS enhanced the uniformity of PVB granules while minimizing PAAS residuals, facilitating the production of films with superior transparency and resistance to yellowing. Investigations into the effects of varying molecular weights, dosages of PAAS, and aging times on the properties of PVB revealed that an increase in PAAS molecular weight correspondingly raised the acetal degree (AD) of PVB without affecting the molecular weight of PVB itself. Furthermore, yhe dosage of PAAS significantly impacted the properties of PVB, whereas aging time exhibits minimal influence on the AD of PVB. 1H‐NMR analysis indicated that the structural stability of PVB is due to the dominance of meso acetal isomers, which improved its mechanical properties when synthesized with PAAS3 (molecular weight 60,000 g/mol), containing 91.5% hexamethylene cycloacetal. Notably, compared to PVB synthesized using sodium dodecyl sulphate (SDS), PVB synthesized with PAAS3 exhibits superior mechanical properties, with significantly improved tensile strength and elongation. This phenomenon is further elucidated by SEM images. A comparison between the optimized self‐made PVB and commercial PVB shows that the self‐made PVB performs better, highlighting the critical role of macromolecular PAAS in enhancing the structure and mechanical properties of PVB.