Design and Preparation of Multiple Function-Integrated Lignin/Tannin/ZnONP Composite Coatings for Paper-Based Green Packaging

Abstract

Lignin/tannin/ZnONP composite coatings were designed for paper-based green packaging. Multiple functions, such as high strength, moisture resistance, low air permeance, heat endurance, UV aging resistance, and antibacterial/mold properties, were successfully integrated into one biobased coating. Prepolymerization improved the physical properties of coatings at high lignin contents. The best ingredient ratio was: 40% lignin, 15% tannin, and 10% ZnONPs (based on tannin weight), and the as-prepared biocoating was labeled LTZn-10. After coated with LTZn-10, the tensile strength and bursting strength of the packaging were efficiently enhanced by more than 3 times and were dramatically increased by 51.6 and 5.6 times at the wet state, respectively, which reveals that the packaging has favorable moisture resistance and it can be used in high humidity environments. Scanning electron microscopy (SEM) proved that most of the pores on the paper were blocked by the coatings, which helped to decrease the air permeance by 10.3 times. Meanwhile, ZnONPs were evenly spread on the coatings, which endowed the packaging with excellent antibacterial/mold performance. No colony or mycelium was found in the test against Gram-negative/positive bacteria and eight common molds. Besides, antibacterial activity is only available while the bacteria come in contact with the coating and no active substances were released into the culture medium, which is a good property that can keep the cargo from contamination of antibacterial agents. In addition, the coated paper presented an improved T g and thermal degradation temperature, indicating that the coated package has favorable thermostability and can maintain its outstanding physical properties in a wider temperature range. Lignin and tannin promoted the UV stability and service life of the coated paper, as a rare physical decrease was observed after UV aging for 72 h. The function-integrated biobased coating with favorable sustainability is a good candidate to be widely used in paperbased green packaging fields.

Fast Response and Visual Transparency Switching Hydrochromic Film Based on the Rational Structure of Cellulose/Poloxamer Copolymers Design for Smart Window

“…[ 25 ] The absorption bands at 2938 and 2843 cm –1 were originated from the methyl (–CH 3 ) and methylene (–CH 2 ) groups, respectively. [ 26 ] In addition, the peak of 3326 cm –1 was ascribed to the stretching vibration of the hydroxyl groups (–OH), and the peak of 1059 cm –1 was assigned to the vibration of the hydroxyl groups (–OH). With increasing concentration of CaCl 2 solution, the peak intensity of the OH stretching vibration peak at 3326 cm –1 was enhanced gradually.…”

Valorisation of Underutilized Grass Fibre (Stem) as a Potential Material for Paper Production

“…It indicates the resistance of the laboratory paper handsheet to rupturing, and laboratory paper handsheet with a low burst strength cannot easily retain packed goods and tears [ 53 ]. Besides, the bursting strength also determined the capability of packaging when it was subjected to stacking, collapsing, striking, tearing, and squeezing, all of which were greatly improved multiple times in both dry and wet states [ 54 ]. This study reveals that fibre obtained directly from pulping is simply inadequate for laboratory paper handsheet production.…”

Natural polyphenol tannin-immobilized composites: rational design and versatile applications

“…In recent years, tannins have been prevalent in food packaging because of their antioxidant activity, antimicrobial property, and UV-blocking. 90,324,325 Nevertheless, water-soluble tannin has the problem of easy leaching. Consequently, its immobilization on a substrate is inevitable, where a natural polymer is preferred.…”