All-Cellulose Composite: Influence of Dissolution Time and Moisture Content of the Starting Material on Wet Strength and Barrier Properties

Packaging is essential for the global transport and storage of goods. However, due to the widespread use of non-biodegradable raw materials, it is a topic of environmental discussions. Paper plays an important role in the packaging sector due to the sustainability of the material, its outstanding flexibility and its high specific strength. But paper also has disadvantages. Paper does not possess wet strength and does not provide barrier properties. These disadvantages have so far been overcome by creating coated paper, paper laminates or through the addition of substances during production. An alternative solution could be All-Cellulose Composites (ACC), which are composites completely made of cellulosic materials.Within the scope of this research short process times will be tested to determine if it is possible to achieve an increase in wet strength and barrier effect sufficient for packaging application. In addition, it will be investigated whether moist paper can be converted into ACC and to what extent the moisture content influences the resulting properties. The papers that will be converted are produced from bleached kraft pulp fibres (NBSK) on a Rapid Köthen sheet former. The conversion to ACC takes place via an immersion process. NaOH-urea is used as the solvent system, which is cooled to -12.5 °C. The tests show that a treatment period of just a few seconds is sufficient to significantly improve tensile and wet strength. It still needs to be clarified for what kind of technical applications the barrier properties achieved so far are suitable.