Hygrothermal performance of paper plaster: influence of different types of paper and production methods on moisture buffering

Paper as a material needs a lot of input energy. Many measures have been suggested to recycle paper, but still a huge amount of it ends in landfills. Hereby, one possibility for recycling paper - making paper plaster and putting it into service in indoor environment - is introduced. The study focuses on the moisture buffering properties of paper plaster. Two questions are under consideration in this article. Firstly, how paper type and production method influence the properties (dry density, drying shrinkage) of paper plaster, and secondly, what the material moisture buffering properties of paper plaster are. The plasters for testing were made from four types of paper (printer paper, glossy paper, newsprint and book paper). The production methods used were rumpling, grinding with a shredder or special crusher (prepared for the study) and soaking the paper after that. The dry density of groups varied from approx. 240 kg/m3 to 400 kg/m3. The shrinkage properties were from 3% to 10% in diameter. To evaluate the moisture buffering ability of paper plaster, the methodology introduced in the Nordtest protocol was used. Paper plaster is an outstanding water vapour buffering material [MBV=2.23-3.91 g/(m2·%RH)] belonging to the moisture buffering class "excellent" defined by Rode [15]. From the production methods rumpling gave the best value while printer paper showed the best values from the chosen materials. The tests with glossy paper resulted in modest values. To conclude, all the paper materials and preparation methods introduced in this study can be used to make paper plaster