Rigid Polyurethane Biofoams Filled with Pine Seed Shell and Yerba Mate Wastes

Area of Science:

• Materials Science
• Polymer Chemistry
• Sustainable Materials

Background:

• Agricultural and food industry byproducts like pine seed shells and yerba mate present disposal challenges.
• Valorization of these waste streams into functional materials is crucial for a circular economy.

Purpose of the Study:

• To develop rigid polyurethane foams (RPUFs) incorporating pine seed shells and yerba mate as fillers.
• To investigate the impact of these natural fillers on the chemical, morphological, mechanical, thermal, and colorimetric properties of RPUFs.

Main Methods:

• Pine seed shells and yerba mate were characterized using bench chemistry analyses.
• RPUFs were fabricated with 5, 10, and 15 wt% of each filler.
• Comprehensive characterization of RPUFs including mechanical, thermal, and morphological analyses.

Main Results:

• Yerba mate exhibited good compatibility with the polyurethane matrix, enhancing mechanical properties and thermal stability (up to ~40%).
• Pine seed shells showed poor compatibility, resulting in a significant loss of mechanical properties (up to ~50%).
• Both fillers decreased the glass transition temperature (T_g), with a more pronounced effect from pine seed shells (~-14 °C vs. ~-5 °C).

Conclusions:

• Yerba mate is a promising sustainable filler for improving RPUF performance.
• Pine seed shells are not suitable for reinforcing RPUFs due to incompatibility issues.
• This research highlights the potential of utilizing specific food industry wastes to create value-added materials.