Effect of Modified and Unmodified Oak Bark

• Published in: Materials Vol. 17; no. 9
• Main Authors: Smejda-Krzewicka, Aleksandra, Mrozowski, Konrad, Strzelec, Krzysztof
• Format: Journal Article
• Language: English
• Published: MDPI AG 01.05.2024
• Subjects: Poland; Germany
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma17091968

The study explores the novel use of oak bark (Quercus cortex) as a bio-filler in elastomeric composites, aligning with the global trend of plant-based biocomposites. Both modified and unmodified oak bark were investigated for their impact on the physicochemical properties of natural rubber (NR) composites. The bio-filler modified with n-octadecyltrimethoxysilane exhibited enhanced dispersion and reduced aggregates in the elastomeric matrix. NR composites containing more than 20 phr of unmodified and modified oak bark demonstrated an increased degree of cross-linking (α[sub.c] > 0.21). Mechanical properties were optimal at 10–15 phr of oak bark and the sample with modified bio-filler (10 phr) achieved the highest tensile strength (15.8 MPa). Silanization and the addition of the bio-filler increased the hardness of vulcanizates. The incorporation of oak bark improved aging resistance at least two-fold due to phenolic derivatives with antioxidant properties. Hydrophobicity decreased with added bark, but silanization reversed the trend, making samples with a high content of oak bark the most hydrophobic (contact angle: 129°). Overall, oak bark shows promise as an eco-friendly, anti-aging filler in elastomeric composites, with modification enhancing compatibility and hydrophobicity.