Improving the extensibility of paper: Sequential spray addition of gelatine and agar
Tutkimustuotos › › vertaisarvioitu
|Julkaisu||Nordic Pulp and Paper Research Journal|
|DOI - pysyväislinkit|
|Tila||Julkaistu - 2015|
High extensibility of paper is of key importance for production of novel 3D-packaging materials. The application of agar onto a wet web has been shown to significantly improve the extensibility of dry paper as a result of shrinkage during drying while addition of gelatine strengthens inter-fibre bonding. In this work, these two bio-based materials were applied sequentially to yield paper with higher extensibility compared to that obtained by single component application. We studied the interactions between agar, gelatine and cellulose by using quartz crystal micro-gravimetry and atomic force microscopy. Agar adsorption was significantly improved after priming the cellulose surface with gelatine. This synergistic effect on extensibility only occurred if the protein was added first. It is hypothesized that the gelatine strengthens the interfibre bonds while the polysaccharide forms a film on the web surface, and reinforces it. The extensibility of webs treated with gelatine (4%) and agar (4%) was ca. 15% after unrestrained drying. Such remarkable level of extensibility allows production of tray-like shapes via conventional thermoforming machine to depths of up to 2 cm. Overall, a protocol based on the sequential application of two abundant biopolymers is proposed to enhance formability of paper.