## 2 Materials and Methods
### Testing Methods  
The moisture content of all particles was determined using a KERN DAB moisture analyzer (KERN & Sohn GmbH, Balingen, Germany). The granulometry determination of all particles was conducted with a set of sieves consisting of the bottom (0 mm), 0.063 mm, 0.10 mm, 0.20 mm, 0.50 mm, 0.63 mm, and 1.25 mm sieves. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Component**} & \multicolumn{6}{c}{**Amount of Component, pbw**} \\ \cline{2-6}  & **Control PUR** & **PUR-Verm** & **PUR-Per** & **PUR-VermDex** & **PUR-PerDex** \\ \hline \hline \multicolumn{6}{c}{_Component A:_} \\ BioPolyol RD & 60 & 60 & 60 & 60 & 60 \\ ROKOPOL RF-152 V & 60 & 60 & 60 & 60 & 60 \\ Water & 3 & 3 & 3 & 3 & 3 \\ Polycat 9 & 0.7 & 0.7 & 0.7 & 0.7 & 0.7 \\ ST-52 & 3.6 & 3.6 & 3.6 & 3.6 & 3.6 \\ Filter, wt.% & 0 & 2.5; 5; 7.5; 10 & 2.5; 5; 7.5; 10 & 2.5; 5; 7.5; 10 & 2.5; 5; 7.5; 10 \\ \multicolumn{6}{c}{_Component B:_} \\ Isocyanate & & & Isocyanate index for all compositions—125 & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Composition of polyurethane foam composites with fillers. Fourier transform infrared (FTIR) spectroscopy was conducted for all particles using Lumos II (Bruker Optics GmbH, Ettlingen, Germany). Thirty scans at a 600-4000 cm\({}^{-1}\) range with a scan interval of 4 cm\({}^{-1}\) were taken for each particle type. The dynamic viscosity test was conducted for polyol and filler premixes using an SV-10 viscometer (A&D Company Ltd., Tokyo, Japan) at a velocity of 6 rpm with an accuracy of 0.01 mPa\(\cdot\)s.  
The characteristic foaming times were determined using a stopwatch with an accuracy of 0.5 s according to the requirements of EN 14315-1 [42]. The structural analysis of the Verm, Per, VermDex, and PerDex particles, control PUR foam, and PUR foam composites was performed using an optical microscope Smart 5 MP PRO (Delta Optical, Gdansk, Poland) with a maximum magnification of up to 300 times. The average cell size of the resulting PUR foam composites was obtained using optical images using ImageJ software, v. 1.51j8. The closed-cell content was determined using the EN ISO 4590 [43] method 2 requirements for samples with a size of 100 mm \(\times\) 30 mm \(\times\) 30 mm. The thermal conductivity determination was performed at an average temperature of 10 \({}^{\circ}\)C on samples with a size of 300 mm \(\times\) 300 mm \(\times\) 50 mm, based on EN 12667 [44] requirements, using a heat flow meter FOX 304 (TA Instruments, Newcastle, DE, USA) with active edge insulation. The direction of the heat flow was upward during the test. The difference between cold and hot plates was 20 \({}^{\circ}\)C.  
The short-term water absorption by partial immersion for control rigid polyurethane foam composites and rigid polyurethane foam composites filled with Verm, Per, VermDex, and PerDex particles was determined based on the ISO 29767 [45] method A requirements for samples measuring 200 mm \(\times\) 200 mm \(\times\) 50 mm. Excess water in the samples was drained for 10 min using a drainage stand at 45\({}^{\circ}\) after the test. The surface hydrophobicity of control rigid polyurethane foam and rigid polyurethane foam composites filled with different particles was determined by the water contact angle method. The test was implemented using a goniometer with an optical system (Ossila Ltd., Sheffield, UK) to capture the angle of water drop on the tested surfaces. Water drops of 1 \(\upmu\)L were deposited using a micrometer syringe. The results were taken 10 s after water droplet deposition. Measurements were done at least three times on each sample. The tensile and compressive strengths were determined in accordance with EN 1607 [46] and ISO 29469 [47] requirements. The samples used for the tests were 50 mm \(\times\) 50 mm \(\times\) 50 mm in size. A Universal Testing Machine, H10 KS Hounsfield (Tinius Olsen Ltd., Surrey, UK), will monitor the behavior of the samples during compression and tension.