Cappello Miriam, Rossi Damiano, Filippi Sara, Cinelli Patrizia, Seggiani Maurizia
Department of Civil and Industrial Engineering, University of Pisa, Largo Lucio Lazzarino 2, 56122 Pisa, Italy.
Materials (Basel). 2023 Jan 6;16(2):570. doi: 10.3390/ma16020570.
This study focused on the development of a novel biocomposite material formed by a thermoplastic biodegradable polyester, poly(butylene succinate--adipate) (PBSA), and a carbonaceous filler as biochar (BC) derived by the pyrolysis of woody biomass waste. Composites with various BC contents (5, 10, 15, and 20 wt.%) were obtained by melt extrusion and investigated in terms of their processability, thermal, rheological, and mechanical properties. In all the composites, BC lowered melt viscosity, behaving as a lubricant, and enhancing composite extrudability and injection moulding at high temperatures up to 20 wt.% of biochar. While the use of biochar did not significantly change composite thermal stability, it increased its stiffness (Young modulus). Differential scanning calorimeter (DSC) revealed the presence of a second crystal phase induced by the filler addition. Furthermore, results suggest that biochar may form a particle network that hinders polymer chain disentanglement, reducing polymer flexibility. A biochar content of 10 wt.% was selected as the best trade-off concentration to improve the composite processability and cost competitiveness without compromising excessively the tensile properties. The findings support the use of biochar as a sustainable renewable filler and pigment for PBSA. Biochar is a suitable candidate to replace more traditional carbon black pigments for the production of biodegradable and inexpensive innovative PBSA composites with potential fertilizing properties to be used in agricultural applications.
本研究聚焦于一种新型生物复合材料的开发，该材料由热塑性可生物降解聚酯聚（丁二酸丁二醇酯-己二酸丁二醇酯）（PBSA）和作为生物炭（BC）的碳质填料组成，生物炭由木质生物质废料热解制得。通过熔融挤出获得了具有不同BC含量（5、10、15和20 wt.%）的复合材料，并对其加工性能、热性能、流变性能和力学性能进行了研究。在所有复合材料中，BC降低了熔体粘度，起到润滑剂的作用，并提高了复合材料在高达20 wt.%生物炭含量时的挤出性和高温注塑成型性能。虽然生物炭的使用并未显著改变复合材料的热稳定性，但提高了其刚度（杨氏模量）。差示扫描量热仪（DSC）显示，填料的加入诱导产生了第二晶相。此外，结果表明生物炭可能形成颗粒网络，阻碍聚合物链的解缠，降低聚合物的柔韧性。选择10 wt.%的生物炭含量作为最佳折衷浓度，以提高复合材料的加工性能和成本竞争力，同时不过度损害拉伸性能。这些发现支持将生物炭用作PBSA的可持续可再生填料和颜料。生物炭是一种合适的候选材料，可替代更传统的炭黑颜料，用于生产具有潜在施肥性能的可生物降解且廉价的创新PBSA复合材料，以用于农业应用。
