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Films derived from thermoplastic starch/alginate/spent coffee grounds for food packaging applications

Abstract In this study, spent coffee grounds (SCG) were utilized as a reinforcing biowaste filler in thermoplastic starch/alginate (TPS-Alg) films. Wet ball milling was used to reduce the SCG particle size. The UV transmission barrier of the TPS-Alg films comprising dark brown SCG particles was 1.5–3.4 times higher than that of binary matrices. The incorporation of SCG induced several voids within the polymeric chains, decreasing the moisture content by 2.10% and reducing the water vapor permeability from (10.50?±?1.07) × 10??13 to (9.03 (pm) 1.69) × 10??13 ng·s??1 m??2 Pa??1. A slight improvement in the thermal stability of the TPS-Alg/SCG blends was observed in comparison to that of the pure TPS-Alg, owing to the partial substitution of TPS with SCG. The notable tensile strength and tensile modulus of TPS-Alg/SCG-10 were respectively 67.6 (pm) 6.1 MPa and 4.7  (pm) 0.3 GPa in spite of the stress concentration and plasticizing effects from SCG fillers. The overall results indicate a significant potential of the as-developed material for application in food packaging.

Publication date: 09/05/2023

Journal of Polymer Research


This project has received funding from the Bio Based Industries Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under grant agreement No 837761.