Structure–Property Relationships in Polyethylene-Based Composites Filled with Biochar Derived from Waste Coffee Grounds

Abstract

In this work, biochar (BC) derived from spent coffee grounds has been incorporated into high density polyethylene (PE) through melt mixing. The influence of the filler content on the rheological and thermal behavior of the obtained composites was assessed. In particular, a rheological study was performed systematically using different flow fields, including linear and nonlinear dynamic shear flow, revealing that the dynamics of PE macromolecules in the composite materials are slowed down because of the confinement of the polymer chains onto the filler surface and/or within the BC porous structure. Oscillatory amplitude sweep tests indicated that composites show weak strain overshoot behavior in the nonlinear regime: This finding clearly proves the formation of weak structural complexes, which cause a retardation of the macromolecular chains dynamics. Furthermore, the embedded BC particles were able to improve the thermo-oxidative stability of PE-based composites, remarkably increasing the PE decomposition temperatures.

Poly(lactic Acid)–Biochar Biocomposites: Effect of Processing and Filler Content on Rheological, Thermal, and Mechanical Properties

“…The heating ramp rate of the tubular furnace was set at 5 • C/min; after the pyrolysis step, the material was manually ground in a mortar, achieving an average size of 10 µm. Further characteristics of the obtained BC particles are reported in [32].…”

Development of Coffee Biochar Filler for the Production of Electrical Conductive Reinforced Plastic

“…Coffee wastes have been also used as feedstock for pyrolytic conversion producing hydrogen-rich gas [8] and fuel-quality biochar [9]. Biochar has been used not only as solid fuel but also as high performance material [10,11], as a flame retardant additive [12,13], for electrochemical [14] and energy storage applications [15] and for production of composites [16][17][18][19].…”

Effect of incorporation of microstructured carbonized cellulose on surface and mechanical properties of epoxy composites

“…described the influence of biochar surface structures on brittleness or ductility of epoxy materials showing how smooth surface could enhance the maximum elongation. Nonetheless, a comprehensive explanation of biochar‐polymer interactions is quite challenging due to all the particle properties (i.e., porosity, shape, residual groups, surface area) . A reasonable approach is represented by the study of a simplified system containing particles with a simply well known shape, the same residual groups and without high structured surfaces.…”