Enhanced barrier performance of silane-modified anionic polysaccharides in packaging paper coatings: Carboxymethyl glucomannan, κ-carrageenan, and carboxymethyl cellulose.

Abstract

Rising environmental concerns have driven biopolymer coatings for paper packaging; however, their water solubility and fragility hinder water barrier and mechanical performance. To address these issues, our group developed a series of novel silane-modified polysaccharides by incorporating potassium methyl siliconate (PMS) into various anionic biopolymers, namely carboxymethyl glucomannan (CMKGM), κ-carrageenan (κC), and carboxymethyl cellulose (CMC). This two-component system achieved hydrophobic surfaces with water contact angle (WCA) exceeding 130° for CMKGM and CMC-based (versus 114° for the base paper), a water vapour transmission rate (WVTR) reduced by up to 32.9% (from 329.1 to 220.7 g/m2.day), a reduction in water absorption up to 46.8% (Cobb60 from 61 to 32.6 g/m2), improved mechanical strength ranging from approximately 2.8- to 6.1-fold relative to the base paper and provided oil resistance reached kit rating 11, with maintaining oil barrier performance for over three months. Furthermore, increasing the cross-linking time reduced WVTR and Cobb60 values by up to 69.6% (CMC-PMS 48 h vs base paper) and 71.2% (CMKGM-PMS 48 h vs base paper) while preserving the mechanical integrity and oil resistance. This efficient and low-chemical design approach leveraging silane-modified polysaccharides is expected to serve as an eco-friendly alternative to conventional synthetic paper coating options and to offer a viable solution for packaging technologies.