The development of composite materials from alternative raw materials, and the design of their properties for the intended purpose is an integral part of the rational management of raw materials and waste recycling. The submitted paper comprehensively assesses the physical and mechanical properties of sandwich composite material made from particles of winter rapeseed stalks, geopolymer and reinforcing basalt lattices. The developed composite panel is designed for use as a filler in constructions (building or building joinery). The observed properties were: bending characteristics, internal bonding, thermal conductivity coefficient and combustion characteristics. The results showed that the density of the particleboard has a significant effect on the resulting mechanical properties of the entire sandwich panel. On the contrary, the density of the second layer of the sandwich panel, geopolymer, did not have the same influence on its mechanical properties as the density of the particleboard. The basalt fibre reinforcement lattice positively affected the mechanical properties of sandwich composites only if it was sufficiently embedded in the structure of the particle board. All of the manufactured sandwich composites resisted flame for more than 13 min and the fire resistance was positively affected by the density of the geopolymer layer.

Bending rigidity is a significant property of textiles that influences their further behavior, for example draping and wrinkling. The thorough analysis of draping and wrinkling behavior of textiles requires also knowledge of bending rigidity of the textiles in different directions, the so-called anisotropy of bending rigidity. Anisotropy of bending rigidity has been so far mostly measured on rectangular shaped samples; nevertheless, the circular shape seems to be the ideal one. This article presents device TH-7, which enables one to measure this non-standard circular shaped sample. Comparing the results of measuring of bending rigidity on the standard device KES-FB2 with the results of measuring on device TH-7, we can see a very good correspondence, that is, the value of the correlation coefficient equals 0.9. The described way of measuring the anisotropy of bending rigidity on circular samples will speed up and improve the quality of further research in the field of influence of the textile structure (weave, sett) on bending rigidity and, consequently, on draping and wrinkling of the textile.

The submitted paper deals with the physical and mechanical properties of geopolymer composite materials reinforced with natural fibres. For this study, we aimed to develop a geopolymer composite reinforced with long flax fibres, which were implemented in the geopolymer in the form of a nonwoven fabric that reinforced the structure of the geopolymer over the entire thickness of the board. In order to compare the properties of the developed composite with natural fibres, a geopolymer without fibres and a geopolymer reinforced with basalt fibres were also produced. The monitored mechanical properties were impact bending, bending strength and compressive strength. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and microscopic analysis were also carried out. The results clearly showed the positive effect of the addition of natural fibres on impact bending and bending strength. However, the addition of natural fibres in the form of a nonwoven fabric significantly increased the variability of the properties of the developed composites. In addition, a different pattern of joint failure was noted between geopolymer reinforced with flax fibres and geopolymer reinforced with basalt fibres.

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