摘要
In order to pursue high performances of starch-based composite films, three types of corn starch, normal corn starch (CS) and high amylose corn starches with 50 % (G50) and 68 % (G68) of amylose contents, were chosen to independently blend with polyvinyl alcohol (PVA) to prepare composite films with the aid of glycerol via the solution casting method, using glutaraldehyde as a chemical cross linker, focusing on the impact of amylose content on mechanical and physicochemical properties of composite films. Three types of starch presented various film forming behavior and the higher amylose content reinforced intermolecular cross-linking inducing the enhanced strength and brittleness and water resistance of films. For starch films without PVA, G68 and G50 films possessed 2.68 and 3.60 times of tensile strength as CS film. Blending PVA into starch significantly promoted the flexibility of all the films and suppressed hydrophilicity of films. The elongation at break of CS, G50 and G68 films blended 30 % PVA were increased by 13.10, 16.67 and 14.13 times, respectively. With the increase of PVA proportion, the tensile strength of CS films enhanced but that of G50 and G68 films decreased. It revealed a hierarchy in intermolecular cross-linking strength: amylose-amylose > amylose-PVA > amylopectin-PVA > amylopectin-amylopectin. Three types of starch composite films blended with 30 % PVA exhibited integrated structures and improved mechanical properties and water resistance, accompanying antimicrobial activity. The optimal tensile strength and water vapor permeability performed in G50 film were 21.80 MPa of and 4.10 × 10 −10 g m −1 s −1 Pa −1 , respectively. G68 film had suboptimal strength and water resistance. Incorporating of more than 30 % PVA was adverse to component compatibility and the integrity of three types of starch-PVA composite films, weakening the strength and water resistance of films.
危险品化学品经营许可证（带存储）