Study of enzymatic degradation and water absorption of nanocomposites polyvinyl alcohol/starch/carboxymethyl cellulose blends containing sodium montmorillonite clay nanoparticle by cellulase and α-amylase

• Enzymatic degradation with α-amylase of nanocomposites were investigated.
• Enzymatic degradation with cellulase of nanocomposites were investigated.
• Water absorption of nanocomposites was investigated.
• Blends with MMT content at 5% exhibited a significantly reduced rate and extent of starch hydrolysis.
• The susceptibility to enzymatic degradation varies in the order: PVA/S/CMC > PVA/S/CMC/MMT.

The aims of the study were to investigate the effect of polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC) and sodium montmorillonite clay (MMT-Na) content within the starch (S) blends on the rate and extent of starch enzymatic hydrolysis using enzymes α-amylase and cellulase. The results of this study have revealed that blends with MMT-Na content at 5 wt% exhibited a significantly reduced rate and extent of hydrolysis. The results suggest that this may have been attributed to interactions between PVA S/CMC and MMT-Na that further prevented enzymatic attack on the remaining PVA/MMT-Na phases within the blend. The total solids remained after 4320 min were 48.54 wt% (PVA/S/CMC); 53.21 wt% (PVA/S/CMC/1% MMT); 55.84 wt% (PVA/S/CMC/3% MMT); 56.98 wt% (PVA/S/CMC/5% MMT). The rate of glucose production from each nanocomposite substrates was the rapidest for the substrate without MMT-Na and decreased with the addition of MMT-Na, for PVA/S/CMC blend (85.59 μg/ml h), 74.24 μg/ml h (PVA/S/CMC/1% MMT), 63.24 μg/ml h (PVA/S/CMC/3% MMT) and 61.74 μg/ml h for (PVA/S/CMC/5% MMT). The rate of hydrolysis was the rapidest for the substrate PVA/S/CMC and decreased enzymatic degradation behavior of sodium montmorillonite-containing nanocomposites of PVA/CMC with starch was based on the determinations of weight loss and the reducing sugars. The degraded residues have been examined by FT-IR spectroscopy and scanning electronic microscopy (SEM) and UV–vis spectroscopy.