PU/Lignocellulosic Composites Produced from Recycled Raw Materials

Abstract

Lignocellulosic composites are biodegradable, have low cost, neutrality to CO 2 emission, easily processed, easily available and pause no health risks, therefore these materials have been the subject of an increase of interest. In addition, there is a continuous demand of materials obtained from renewable resources and waste recycling. In that sense, in this study polyurethane (PU) residues were mixed with residues of cork and pine (up to 70 wt/wt) to produce 100% recycled composites. Cork is well known to be a light and a thermal insulator material, so the addition of cork granulates decreased both density (circa 51%) and thermal conductivity (circa 61%) of the composites. In turn, pine fibers are hydrophilic and have cylindrical shapes, thus their presence increased the water absorption and improved the mechanical properties of the composites. From the results, these composites proved to be suitable to be used as structure and thermal insulation materials with the advantage of being produced from 100% recycled raw-materials.

Characterization of a Thermal Insulating Material Based on a Wheat Straw and Recycled Paper Cellulose to Be Applied in Buildings by Blowing Method

“…In image (d), the particles of boron salts are clearly observed, which are homogeneously mixed throughout the material. This fibrous macrostructure is similar to other natural fibers used for insulation applications reported in other works, such as pine fiber [51], palm surface fiber [49] or pisum sativum [2].…”

“…In images (b) and (c), in addition to observing in greater detail th of the cellulose, small white clusters begin to be observed, which are salts that are present in the analyzed cellulose and that give it the ab action of fire and to repel insects, among others. In image (d), the part are clearly observed, which are homogeneously mixed throughout the brous macrostructure is similar to other natural fibers used for insulatio ported in other works, such as pine fiber [51], palm surface fiber [49] [2]. At approximately 3290 (cm −1 ), an important absorption band is observed, corresponding to O-H bonds and belonging to the hydrogen bridges between the hydroxyl groups of the glucose chains that compose the cellulose, as well as belonging to the remains of water that could have been in both samples.…”

“…These values of thermal stability are slightly lower than other insulation composites with lignocellulosic fibers in their composition [49][50][51]. However, the results suggests that these materials can be used as a building material, since the stability temperature of 170-260 • C is enough for building applications at low and medium temperatures [52].…”

Modified cork/SEBS composites for 3D printed elastomers

“…Hence, to expand the range of applications of 3D printed objects in areas such as biomedical, mechanical or electronical, the use of natural fillers based composites has been widely studied 16 . Yet, the compatibility between fillers and matrix is crucial for the performance of the composites 17–21 . The differences between the hydrophilic character of filler and matrix may require the use of additives or physical/chemical modification of the filler to improve compatibility and interfacial adhesion 12 …”

“…16 Yet, the compatibility between fillers and matrix is crucial for the performance of the composites. [17][18][19][20][21] The differences between the hydrophilic character of filler and matrix may require the use of additives or physical/chemical modification of the filler to improve compatibility and interfacial adhesion. 12 Cork is a natural, renewable and sustainable raw material with low density, low thermal conductivity and high elasticity, [22][23][24] therefore, it is used as bottle stoppers 25 or building materials.…”