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Two-way shape memory polymer can exhibit reversible shape transformation, which shows great application potential as a smart material. It is necessary to develop new reversible shape memory composite systems to achieve accurate and wide-range control of two-way shape memory behavior, especially under the condition of no external force. A chemically cross-linked two-component crystalline block copolymer was prepared based on the independence of crystallization of PLA and PCL. The mechanism of two-way shape memory behavior under stress-free condition of the material is revealed.The results show that both the crystallization and thermal property of PLA/PCL-PU can be signi cantly changed by adjusting the proportion between PLA and PCL, and the dosage of crosslinking agent, and thus the shape memory property of PLA/PCL-PU can be regulated accordingly. The two-way shape recovery rate of the material can reach to 41.11%. This work provides a facile strategy to fabricate a biodegradable thermally induced two-way shape memory material under the stress-free condition with tunable shape memory properties.

A cross‐linked film, based on corn starch/hydroxymethylated alkali lignin, was prepared. The effects of solution casting, pH, and reactant stoichiometries on water absorbability and mechanical properties of the starch/lignin film were studied. The microstructure, morphology, moisture absorbability, and thermal properties of the film were also evaluated. Results showed that the starch/lignin composite film, cast under optimized conditions, was homogeneous and soft. The tensile strength and elongation ratio of the composite film were higher than that of the corn starch film. At a temperature, higher than 320°C, the weight loss rate of the starch/lignin film was lower than that of the starch film and its char residue at 750°C was more than the corn starch film. This showed that the starch/lignin film had better thermal stability at higher temperatures. More importantly, the water absorption rate of starch/lignin film was 238 ± 3 %, which was 1.3 times than that of the corn starch film. The moisture content of the film was also higher than the corn starch sample. Hence, the prepared starch/lignin cross‐linked film can be used as a biodegradable, water absorbent material for packaging and in agricultural mulching.

A degradable starch/lignin blend film was prepared using corn starch and sodium lignosulfonate via a casting and solvent evaporation method. The effect of sorbitol content on the swelling properties of starch/lignosulfonate blend films was investigated. The effect of lignosulfonate content on the swelling and mechanical properties was also studied. The results showed that when the mass ratio of sorbitol to starch changed over a wide range, from 0:9 to 9:9, the water absorption of the blend films increased at first and then decreased. When the mass ratio of lignosulfonate to starch changed in the same range, the ultimate stress of the blend films decreased markedly, while the water absorption and elongation at break did not show any regular pattern. When the mass ratios of sorbitol to starch and lignosulfonate to starch were both 6:9, the resultant film presented good elasticity and improved hydrophobicity compared to those without lignosulfonate.

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