The Effect of Biochar Addition on Thermal Stability and Decomposition Mechanism of Poly(butylene succinate) Bionanocomposites

Katerina Papadopoulou; Evangelia Tarani; Nina Maria Ainali; Konstantinos Chrissafis; Christian Wurzer; Ondřej Mašek; Dimitrios N Bikiaris

doi:10.3390/molecules28145330

The Effect of Biochar Addition on Thermal Stability and Decomposition Mechanism of Poly(butylene succinate) Bionanocomposites

Molecules. 2023 Jul 11;28(14):5330. doi: 10.3390/molecules28145330.

Authors

Katerina Papadopoulou¹, Evangelia Tarani², Nina Maria Ainali¹, Konstantinos Chrissafis², Christian Wurzer³, Ondřej Mašek³, Dimitrios N Bikiaris¹

Affiliations

¹ Laboratory of Polymer Chemistry and Technology, Department of Chemistry, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece.
² Laboratory of Advanced Materials and Devices, Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece.
³ UK Biochar Research Centre, School of GeoSciences, University of Edinburgh, Alexander Crum Brown Road, Edinburgh EH9 3FF, UK.

Abstract

In the present study, poly(butylene succinate) (PBSu) and its bionanocomposites containing 1, 2.5, and 5 wt.% biochar (MSP700) were prepared via in situ melt polycondensation in order to investigate the thermal stability and decomposition mechanism of the materials. X-ray photoelectron spectroscopy (XPS) measurements were carried out to analyze the surface area of a biochar sample and PBSu/biochar nanocomposites. From XPS, it was found that only physical interactions were taking place between PBSu matrix and biochar nanoadditive. Thermal stability, decomposition kinetics, and the decomposition mechanism of the pristine PBSu and PBSu/biochar nanocomposites were thoroughly studied by thermogravimetric analysis (TGA) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). TGA thermograms depicted that all materials had high thermal stability, since their decomposition started at around 300 °C. However, results indicated a slight reduction in the thermal stability of the PBSu biochar nanocomposites because of the potential catalytic impact of biochar. Py-GC/MS analysis was employed to examine, in more detail, the thermal degradation mechanism of PBSu nanocomposites filled with biochar. From the decomposition products identified by Py-GC/MS after pyrolysis at 450 °C, it was found that the decomposition pathway of the PBSu/biochar nanocomposites took place mainly via β-hydrogen bond scission, which is similar to that which took place for neat PBSu. However, at higher biochar content (5 wt.%), some localized differences in the intensity of the peaks of some specific thermal degradation products could be recognized, indicating that α-hydrogen bond scission was also taking place. A study of the thermal stability and decomposition pathway of PBSu/biochar bionanocomposites is crucial to examine if the new materials fulfill the requirements for further investigation for mulch films in agriculture or in electronics as possible applications.

Keywords: biochar; decomposition mechanism; nanocomposites; poly(butylene succinate); thermal degradation.

Grants and funding

This research was funded by the European Community’s Horizon 2020 Framework Program H2020 (grant number 952941, accessed on 1 January 2020, Project: BIOMAC, European Sustainable Biobased Nanomaterials Community; https://www.biomac-oitb.eu/en/normal/home, accessed on 1 January 2020).