Role of amylose and amylopectin in PVA-starch hybrid cryo-gels networks formation from liquid-liquid phase separation

Hypothesis: The role of amylose and amylopectin in the formation of cryogels based on Poly(vinyl alcohol) (PVA) and starch is poorly understood. A systematic investigation of simplified systems containing PVA, amylose, and/or amylopectin constitutes the basis to predict the final features of PVA/starch cryogels by knowing their composition, and the amylose content of the employed raw starches. Experiments: Pre-gel solutions and cryogels containing PVA/amylose, PVA/amylopectin, and PVA/amylose/amylopectin in variable ratios were investigated employing small-angle X-ray scattering (SAXS), confocal laser scanning microscopy (CLSM), differential scanning calorimetry (DSC), and rheological measurements. The gel fraction (G%) of 23 samples with variable compositions was calculated and plotted to predict the G% (the gel fraction) of any PVA/amylose/amylopectin mixing ratio. Findings: We report on how the PVA, amylose, and amylopectin composition affect the properties of the final polymer blend and cryogel formation. In particular, PVA/amylose and PVA/amylopectin show different behaviors with respect to cryogel formation. We show that is possible to predict cryogel formation by using the simple G% parameter for any PVA/amylose/amylopectin mixing ratio, ruling out the starch botanical origin in the gel formation. The results reported in this work represent a simple tool, able to predict the formation of high-quality biobased materials that can replace fully synthetic materials with a significantly positive impact on our ecosystem. (c) 2022 Elsevier Inc. All rights reserved.