Thermal conductivity of heat insulation material made from coniferous needles with potato starch binder

In previous experiments made by authors of this research about the possibilities to produce thermal insulation material from coniferous greenery (needles and thin branches), it was found that there is not enough natural resin in coniferous greenery to make sufficiently strong thermal insulation material plates. Therefore it is necessary to add some binder. Potato starch glue was selected as a natural and environmentally friendly binder. For that reason, the aim of the experiments in this study is to evaluate how the quantity of potato starch binder influences the thermal conductivity coefficient of the coniferous needle thermal insulation material. In this study two experiments were performed investigating two - factors proportion of the binder and the coniferous species (pine or spruce). In the first experiment milled fresh coniferous greenery with potato starch binder was used. In the second experiment potato starch was used to band dried needles without the branches. Granulometric content of the raw material was determined in both cases. A total of 14 different samples were prepared and tested in this study, the thermal conductivity coefficient was determined in laboratory conditions for all of the samples. The results are compared with thermal conductivity coefficients of other thermal insulation materials. The possibility to use coniferous greenery to produce thermal insulation material is evaluated. (C) 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.