Biomaterials & Biodevices
Patrick Jahn; Samuel Schabel
Abstract
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 ...
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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.
Sustainable Construction and Building Materials
Christiane Helbrecht; Robert Götzinger; Samuel Schabel
Abstract
An important advantage of paper composites is their sustainability. Natural fibers store CO2 during growth, they are recyclable and may be safely thermally recycled. In this work, composites out of laboratory paper and epoxy resin are generated in a hand lay-up process. The laboratory paper varies in ...
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An important advantage of paper composites is their sustainability. Natural fibers store CO2 during growth, they are recyclable and may be safely thermally recycled. In this work, composites out of laboratory paper and epoxy resin are generated in a hand lay-up process. The laboratory paper varies in the degree of fiber orientation. As a comparison, paper with isotropic fiber orientation is also used. The tensile strength for the isotropic paper composite is about 120 MPa. It can be observed that the tensile strength of the composite tends to increase with the increase of fiber orientation in the paper. The measured tensile strength of the oriented paper composites in the fiber direction is about 150 MPa and in cross fiber direction about 50 MPa. The strength characteristics are comparatively lower than for carbon or glass fiber reinforced composites, but the density of the paper composites investigated here is only about 1.26 g/cm3 and the raw material price is significantly lower making paper composites economically attractive. At the end, strength values are modeled with the rule of mixture as well as with Kröling's strength model. In conclusion, tensile strength of oriented paper composites are higher than of isotropic paper.
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