Preparation method of sodium alginate-polyvinyl alcohol-nano silicon dioxide composite film for food packaging

Abstract

The invention discloses a preparation method of a sodium alginate-polyvinyl alcohol-nano silicon dioxide composite film for food packaging. The preparation method introduces polyvinyl alcohol as one of main raw material ingredients on the basis of a sodium alginate-nano silicon dioxide composite film preparation technology in the prior art, and omits a step of a cross-linking reaction after film casting, thus greatly improving the mechanical performance indexes of the composite film, and better solving the problems that in the prior art, an alginate-based composite film wrinkles, is hard and brittle, and is poor in flatness. The preparation method of the sodium alginate-polyvinyl alcohol-nano silicon dioxide composite film for food packaging is simple in technology; the composite film prepared by the method greatly improves tensile strength, shear strength, flatness and softness performance index on the basis of retaining all good performance indexes of the sodium alginate-nano silicon dioxide composite film in the prior art, thus being more suitable for the use of a food packaging film.

Description

Technical field [0001] The invention relates to a method for preparing a sodium alginate film for food packaging, in particular to a method for preparing a sodium alginate-polyvinyl alcohol-nano silica composite film for food packaging. Background technique [0002] As people’s awareness of environmental protection increases, synthetic plastics from petroleum-based industrial products will gradually be replaced by biodegradable plastic products derived from plant resources. The preparation of environmentally friendly biomass materials will inevitably become one of the most promising materials in the 21st century. [0003] Sodium Alginate, also known as sodium alginate, kelp gum, alginate or alginate, is a natural polysaccharide polymer copolymer extracted from kelp or Sargassum. The source is abundant and due to its practicality, biological phase Capacitive, non-toxic, low-cost, degradable and good film-forming properties. [0004] However, pure sodium alginate film has poor plastic...

AI Technical Summary

Problems solved by technology

Although the composite film cross-linked by calcium chloride meets the mechanical performance index of the food packaging film, the final composite film is correspondingly hard and brittle, with poor flexibility and poor flatness.

[0012] The reason is that: due to Ca 2+ The gel induced by cross-linking is due to the chelation of calcium ions and multiple oxygen atoms in the gulose structural unit, which eventually produces the so-called "eggshell" node region, and the cross-linking is completed instantaneously, therefore, The rapid cross-linking process and high swelling state make the film prone to wrinkling, which makes the film inhomogeneous; in addition, due to the formation of nodes, it is inevitable that the film will shrink greatly after cross-linking and drying.