Preparation and Characterization of Films Based on Disintegrated Bacterial Cellulose and Montmorillonite

Agata Sommer,Piotr Bruździak,Izabela Sinkiewicz,Hanna Staroszczyk

doi:10.1007/s10924-020-01968-5

Agata Sommer, Piotr Bruździak + Show 2 more

Open Access

https://doi.org/10.1007/s10924-020-01968-5

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Abstract

The food packaging materials from natural polymers including polysaccharides offer an ecologically important alternative to commonly used synthetic, non-biodegradable counterparts. The purpose of this work was to modify of bacterial cellulose (BC) leading to the improvement of its functional properties in terms of use as a food packaging material. Effects of disintegration of BC and addition of montmorillonite (MMT) on its water barrier, mechanical and thermal properties were investigated. Disintegration of BC increased its water vapour permeability (WVP) and thermal stability, but decreased its tensile strength (σ). These changes were closely related to the rearrangement of hydrogen-bond network in the BC structure, resulting in a partial conversion from the Iα to Iβ allomorph. The addition of 2% of MMT did not affect WVP and σ of the disintegrated BC (bBC), while the plasticization of the modified bBC generally decreased WVP, and did not increase σ. The improvement in water barrier properties of bBC modified by adding 2% of MMT in the presence of glycerol was caused by the formation of hydrogen bonds between the components of the composite. The results presented show the potential usefulness of BC modified by disintegration and adding 2% of MMT and 10–15% of glycerol as a food packaging material.

Highlights

Biodegradable materials with good water barrier and mechanical properties are gaining increasing interest in the field of food packaging, including disposable packaging
The water vapour permeability (WVP) of bacterial cellulose varies depending on the culture conditions, sample moisture content, the way of BC preparation for measurements, and the measurement conditions [26,27,28]
The influence of disintegration of BC and addition of MMT on its water barrier, mechanical and thermal properties was investigated to see if the so modified BC is suitable for biodegradable food packaging material

Summary

Introduction

Biodegradable materials with good water barrier and mechanical properties are gaining increasing interest in the field of food packaging, including disposable packaging. Materials based on bacterial cellulose (BC) have attracted great attention due to their high purity of cellulose content, refined nanofibrous network and very low cost. BC has better properties than plant cellulose, including higher tensile strength and high fiber content. The BC secreted by Gluconoacetobacter xylinus is made up with cellulose I which contains two regions of higher (crystalline) and lower (amorphous) order. The former region forms a network of strong intra and inter-chain hydrogen bonds between the hydroxyl groups of cellulose chains, giving high tensile strength to the cellulose. Cellulose Iα can be converted to the more thermodynamically stable cellulose Iβ by applying certain treatment processes, for instance by annealing [13], hydrothermal treatment in basic solution [14, 15] and high-temperature treatment in organic solvents and helium gas, complete conversion to Iβ is not achieved [15]

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