Oxygen and water vapor barrier properties of polyvinyl alcohol and zein bilayer‐coated paper

Synthesis of Water-Dispersible Poly(dimethylsiloxane) and Its Potential Application in the Paper Coating Industry as an Alternative for PFAS-Coated Paper and Single-Use Plastics

Polyethylene-, polyvinylidene chloride-, and per- and polyfluoroalkyl substance-coated paper generate microplastics or fluorochemicals in the environment. Here, we report an approach for the development of oil-resistant papers using an environmentally friendly, fluorine-free, water-dispersible poly(dimethylsiloxane) (PDMS) coating on kraft paper. Carboxylic-functionalized PDMS (PDMS-COOH) was synthesized and subsequently neutralized with ammonium bicarbonate to obtain a waterborne emulsion, which was then coated onto kraft paper. The water resistance of the coated paper was determined via Cobb60 measurements. The Cobb60 value was reduced to 2.70 ± 0.14 g/m2 as compared to 87.6 ± 5.1 g/m2 for uncoated paper, suggesting a remarkable improvement in water resistance. Similarly, oil resistance was found to be 12/12 on the kit test scale versus 0/12 for uncoated paper. In addition, the coated paper retained 70-90% of its inherent mechanical properties, and more importantly, the coated paper was recycled via pulp recovery using a standard protocol with a 91.1% yield.

A facile strategy to fabricate antibacterial hydrophobic, high-barrier, cellulose papersheets for food packaging

As a traditionally used packaging material, natural cellulose-based paper has poor barrier properties to water and oxygen, which severely limits its wide application in food packaging. In this study, we report a new sustainable approach to producing hydrophobic, high-barrier, and antibacterial packaging materials from cellulose paper. In this process, commercially available microcrystalline cellulose was first modified by long-chain stearic acid to form hydrophobic microcrystalline cellulose ester and then mixed with stearic acid as filler in the subsequent surface coating of bagasse fibre paper. The microcrystalline cellulose ester/stearic acid-coated paper (MSP) exhibited good water repellency and oxygen barrier activity due to a continuous hydrophobic film that formed, which completely covered the pores of the original bagasse fibre paper. The coated MSP sample also showed excellent dimensional stability in water and a good wet tensile strength of 16 MPa. In addition, poly(hexamethylene guanidine) (PHMG) was chemically grafted onto the free carboxyl groups of the MSP surface layer, and the resulting MSP-g-PHMG samples exhibited excellent antibacterial activity against Escherichia coli and Listeria monocytogenes. The biodegradable cellulose-based MSP-g-PHMG sample significantly delayed the decay of raspberry during storage, indicating its potential application in food packaging.

Bio-based materials for barrier coatings on paper packaging

Research into alternative packaging materials is becoming more and more popular as a result of growing eco-friendly concerns regarding the usage of some petroleum-based polymeric packaging materials and coatings, as well as growing buyer demands for products with nutritious quality and extended shelf lives. Barrier coatings made of naturally renewable biopolymers can be applied to paper packing materials. These biopolymer coatings have the potential to replace the current synthetic paper and paperboard coatings, are strong oxygen and oil barriers, and may prevent the unintended moisture transfer in food goods. An appealing method of controlling the growth and spread of microorganisms in food packaging is the integration of antimicrobial compounds into coatings to create active/functional paper-based packaging materials. Here, in this review of the oxygen/moisture barrier, mechanical, and other characteristics of paper coated with bio-based materials. Examples are used to discuss the current and future uses of bio-based material coatings on paper packaging materials to improve barrier performance.