We investigated the effect of the type and amount of expandable graphite (EG) and blackcurrant pomace (BCP) on the flammability, thermal stability, mechanical properties, physical, and chemical structure of viscoelastic polyurethane foams (VEF). For this purpose, the polyurethane foams containing EG, BCP, and EG with BCP were obtained. The content of EG varied in the range of 3–15 per hundred polyols (php), while the BCP content was 30 php. Based on the obtained results, it was found that the additional introduction of BCPs into EG-containing composites allows for an additive effect in improving the functional properties of viscoelastic polyurethane foams. As a result, the composite containing 30 php of BCP and 15 php of EG with the largest particle size and expanded volume shows the largest change in the studied parameters (hardness (H) = 2.65 kPa (+16.2%), limiting oxygen index (LOI) = 26% (+44.4%), and peak heat release rate (pHRR) = 15.5 kW/m² (−87.4%)). In addition, this composite was characterized by the highest char yield (m₆₀₀ = 17.9% (+44.1%)). In turn, the change in mechanical properties is related to a change in the physical and chemical structure of the foams as indicated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis.

Taking into account the circular economy guidelines and results of life cycle analyses of various materials, it was proposed to use a blackcurrant pomace filler in the production process of viscoelastic polyurethane (PUR) foams intended for application as mattresses, pillows, or elements for orthopedics. Open-cell viscoelastic PUR foams containing 10–60 per hundred polyols (php) blackcurrant pomace were prepared. It was found that after introducing the filler to the PUR foam formulation, the speed of the first stage of the foaming process significantly decreases, the maximum temperature achieved during the synthesis drops (by 30 °C for the foam containing 40 php of filler compared to unfilled foam), and the maximum pressure achieved during the synthesis of foam containing 20 php is reduced by approximately 57% compared to the foam without filler. The growth time of the foams increases with increasing the amount of introduced filler; for the foam containing 60 php, the time is extended even by about 24%. The effect of the filler on the physical, morphological, mechanical, and functional performances of PUR foam composites has been analyzed. The use of 60 php as the filler reduced the hardness of the foams by approximately 30% and increased their comfort factor from 3 to 5.

Viscoelastic polyurethane (VEPUR) foams with increased thermal resistance are presented in this article. VEPUR foams were manufactured with the use of various types of flame retardant additives and keratin fibers. The structure of the modified foams was determined by spectrophotometric-(FTIR), thermal-(DSC), and thermogravimetric (TGA) analyses as well as by scanning electron microscopy (SEM). We also assessed the fire resistance, hardness, and comfort coefficient (SAG factor). It was found that the use of keratin filler and flame retardant additives changed the foams’ structure and properties as well as their burning behavior. The highest fire resistance was achieved for foams containing keratin and expanding graphite, for which the reduction in heat release rate (HRR) compared to VEPUR foams reached 75%.

The subject of the research presented in this article are viscoelastic polyurethane foams (VPF) made using a fillers from coffee grounds. The foams were made with varying content of coffee fillers. Foams and fillers were characterized by means of techniques such as infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry and cone calorimeter. The changes in the microstructure of the foams were analyzed using a scanning electron microscope. Foam properties in the compression test was assessed. As a result, it was concluded that the use filler from coffee grounds causes a significant reduction in compression set of foams after compression by 75% and by 90% of the height of the samples. It was shown that these changes are caused by changes in the chemical structure of the macromolecules of these foams but also in their structure. After addition the filler, all foams have permanent deformations with a value below the permissible limit of 10%. Addition of 20% by mass of filler caused by a decrease in the rate of heat release and the rate of smoke release during foam combustion.

The article presents an assessment of the possibilities of producing viscoelastic open cell polyurethane (PUR) foams produced with a natural filler in the form of mint leaves. PUR foams containing from 10 to 30 wt % of mint were produced. Chemical structure, thermal and mechanical properties of the foams were assessed. It was found that the filler containing 7 wt % of water caused significant changes in the foam characteristics. In composite foams, the content of urea and hydrogen bonds increased with higher mint contents. The hardness and comfort factor of composite foams also increased. The introduction of a filler containing a significant amount of water caused a change in the porosity and wall thickness of composite foams resulting in a significant increase in their permanent deformations