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Thermoplastic starch (TPS) was prepared from cassava starch blended with glycerol (70:30 w/w). Gelatin (Gel) was incorporated into the TPS in water. The TPS/Gel was melt-blended with polyethylene-grafted-maleic anhydride (PEMAH). Maximum tensile strength of the TPS/PEMAH/Gel10 (29.3 MPa) increased significantly compared to the TPS/PEMAH blend (6.3 MPa), while elongation at break was 70%. The morphology of the TPS/PEMAH showed co-continuous morphology, while phase inversion occurred with the addition of Gel. The Gel was dispersed in the TPS matrix and covered the PEMAH. The TPS/PEMAH/Gel was nanoparticles (200 nm) in the TPS matrix. It showed two melting temperatures for PEMAH due to two structures with different crystal sizes. Melt viscosity of the TPS/PEMAH was enhanced with increasing Gel as the reaction induced chain extension. FTIR and rheology measurements confirmed the reaction between -NH groups of Gel and MAH groups of PEMAH. This reaction improved interfacial adhesion, morphology, and the mechanical properties of the blends., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Corn starch was melt-blended with glycerol (70/30) to prepare thermoplastic starch (TPS) at 140 °C for 10 min. The TPS was melt-blended with polyethylene grafted with maleic anhydride (PE-MAH) and carboxymethyl cellulose (CMC) to improve the properties of the TPS. Phase determination analysis and SEM images demonstrated that the morphology of the TPS/PE-MAH/CMC blend consisted of PE-MAH particles dispersed in the TPS matrix. The tensile strength and elongation were found to have improved with the addition of CMC 5 wt%. Adhesion between the polymers was observed by the asymmetric double-cantilever beam (ADCB) method. The PE-MAH/(TPS + CMC) sample showed high fracture toughness (Gc), which is related to the adhesion energy between the two polymers. This is suggestive of interactions between the MAH groups of PE-MAH and CMC. FT-IR results indicated that the neutralization and aggregation were formed by Na + ions of CMC and the MAH of PE-MAH, which increased the interfacial adhesion between TPS and PE-MAH blend. The improvement in the mechanical properties of the TPS/PE-MAH/CMC blend is concluded to be because of the increase in the interfacial adhesion between TPS and PE-MAH by these neutralization and aggregation processes., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Cassava starch was melt-blended with glycerol (70/30wt%/wt%) at 140°C to prepare thermoplastic starch (TPS). Chitosan (CTS) was premixed with starch and glycerol, in acidified water (lactic acid 2wt%), at 1, 5 and 10wt%/wt%. TPS/CTS was then melt-blended (160°C) with polyethylene-graft-maleic anhydride (PE-MAH). Phase determination and scanning electron microscopy indicated TPS/PE-MAH/CTS had a co-continuous morphology and CTS-induced phase inversion to give dispersed PE-MAH particles in a TPS matrix. Tensile strength at break and elongation, melt viscosity, fracture toughness and water contact angle of TPS/PE-MAH were improved by CTS incorporation. TPS/PE-MAH/CTS blends decreased the melting temperature of TPS and PE-MAH compared to the neat polymers. FTIR confirmed a reaction had occurred between amino groups (NH2) of CTS and the MAH groups of PE-MAH. This reaction and the enhanced miscibility between TPS and CTS improved the mechanical properties of the TPS/PE-MAH/CTS blend, particularly at 5wt%/wt% CTS., (Copyright © 2016 Elsevier Ltd. All rights reserved.)