Mechanical and Rheological Evaluation of Polyester-Based Composites Containing Biochar

Sebastian Jurczyk; Jacek Andrzejewski; Adam Piasecki; Marta Musioł; Joanna Rydz; Marek Kowalczuk

doi:10.3390/polym16091231

Mechanical and Rheological Evaluation of Polyester-Based Composites Containing Biochar

Polymers (Basel). 2024 Apr 28;16(9):1231. doi: 10.3390/polym16091231.

Authors

Sebastian Jurczyk¹, Jacek Andrzejewski², Adam Piasecki³, Marta Musioł⁴, Joanna Rydz⁴, Marek Kowalczuk⁴

Affiliations

¹ Łukasiewicz Research Network-Institute for Engineering of Polymer Materials and Dyes, 55. M. Skłodowska-Curie St., 87-100 Toruń, Poland.
² Institute of Materials Technology, Polymer Processing Division, Faculty of Mechanical Engineering, Poznań University of Technology, 3. Piotrowo St., 61-138 Poznan, Poland.
³ Institute of Materials Engineering, Faculty of Materials Engineering and Technical Physics, Poznan University of Technology, 3. Piotrowo St., 61-138 Poznan, Poland.
⁴ Centre of Polymer and Carbon Materials, Polish Academy of Sciences, 34. M. Curie-Skłodowska St., 41-819 Zabrze, Poland.

Abstract

The use of biodegradable polymers as matrices in composites gives a wide range of applications, especially in niche areas. The assessment of the effect of the filler content on the change of mechanical properties makes it possible to optimize the composition for specific needs. Biochar was used as a filler in the studied composites with two different biodegradable blends as a matrix. Poly(1,4-butylene adipate-co-1,4-butylene terephthalate)/polylactide/biochar (PBAT/PLA/BC) and polylactide/poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate]/biochar (PLA/P(3HB-co-4HB)/BC) composites with 0, 10, 15, 20 and 30 wt% of biochar underwent mechanical tests. The test results revealed a change in the properties of the composites related to the filler content. The results of the tensile test showed that increasing the biochar content increased the tensile modulus values by up to 100% for composites with 30 wt% of biochar, compared to unfilled matrices, and decreased the elongation associated with the breaking of PBAT/PLA and PLA/P(3HB-co-4HB) matrix composites. The elongation values at break of PBAT/PLA and PLA/(3HB-co-4HB) composites with 30 wt% biochar were reduced by 50% and 65%, respectively, compared to the unfilled matrices. PLA/P(3HB-co-4HB) matrix composites, in contrast to PBAT/PLA/BC, showed a decrease in tensile strength with the increases in filler content from 35.6 MPa for unfilled matrix to 27.1 MPa for PLA/P(3HB-co-4HB)/BC30 composites. An increase in filler content increased the brittleness of the composites regardless of the matrix used, as determined under the Charpy impact-test. This phenomenon was observed for all tested PLA/P(3HB-co-4HB) composites, for which the impact strength decreased from 4.47 kJ/m² for the matrix to 1.61 kJ/m² for the composite containing 30 wt% biochar. PBAT/PLA-based composites with 10 wt% of biochar showed slightly lower impact strength compared to the unfilled matrix, but composites with 30 wt% biochar showed 30% lower impact strength than PBAT/PLA. The complex viscosity value increased with increased filler content. For all composites tested on both polyester matrices, the viscosity decreased with increasing angular frequency.

Keywords: biochar; biodegradable polymers; composites; mechanical test.

Grants and funding

This research was partially funded by the Ministry of Science and Higher Education in Poland as part of the statutory subsidy for the Poznan University of Technology, project no. 0613/SBAD/4820.