Sustainable Thermoplastic Starch Biocomposites from Coffee Husk and Mineral Residues: Waste Upcycling and Mechanical Performance

Laysa Silva Barboza, Pedro Afonso de Moraes Paes, Maria Eduarda Alexandrino Alves, Marceli do Nascimento da Conceição (), Nancy Camilly Marques de Sena, Pedro Henrique Poubel Mendonça da Silveira (), Roberto Carlos da Conceição Ribeiro, Neyda de la Caridad Om Tapanes and Daniele Cruz Bastos ()
Additional contact information
Laysa Silva Barboza: Campus Zona Oeste, State University of Rio de Janeiro, UERJ, Avenida Manuel Caldeira de Alvarenga, 1203, Campo Grande, Rio de Janeiro 23070-200, RJ, Brazil
Pedro Afonso de Moraes Paes: Campus Zona Oeste, State University of Rio de Janeiro, UERJ, Avenida Manuel Caldeira de Alvarenga, 1203, Campo Grande, Rio de Janeiro 23070-200, RJ, Brazil
Maria Eduarda Alexandrino Alves: Campus Zona Oeste, State University of Rio de Janeiro, UERJ, Avenida Manuel Caldeira de Alvarenga, 1203, Campo Grande, Rio de Janeiro 23070-200, RJ, Brazil
Marceli do Nascimento da Conceição: Federal University of Rio de Janeiro, UFRJ, Av. Athos da Silveira Ramos, 149–Cidade Universitária, Rio de Janeiro 21941-909, RJ, Brazil
Nancy Camilly Marques de Sena: Campus Zona Oeste, State University of Rio de Janeiro, UERJ, Avenida Manuel Caldeira de Alvarenga, 1203, Campo Grande, Rio de Janeiro 23070-200, RJ, Brazil
Pedro Henrique Poubel Mendonça da Silveira: Department of Materials Engineering, Military Institute of Engineering, IME, Praça General Tiburcio 80, Urca, Rio de Janeiro 22290-270, RJ, Brazil
Roberto Carlos da Conceição Ribeiro: Centre for Mineral Technology, CETEM, Rio de Janeiro 21941-908, RJ, Brazil
Neyda de la Caridad Om Tapanes: Campus Zona Oeste, State University of Rio de Janeiro, UERJ, Avenida Manuel Caldeira de Alvarenga, 1203, Campo Grande, Rio de Janeiro 23070-200, RJ, Brazil
Daniele Cruz Bastos: Campus Zona Oeste, State University of Rio de Janeiro, UERJ, Avenida Manuel Caldeira de Alvarenga, 1203, Campo Grande, Rio de Janeiro 23070-200, RJ, Brazil

Sustainability, 2025, vol. 17, issue 20, 1-20

Abstract: Thermoplastic starch (TPS) is a biodegradable polymer from renewable sources, but its limited mechanical and thermal properties restrict wider industrial use compared to petroleum-based plastics. In this study, TPS-based biocomposites were developed and optimized by incorporating agricultural and mineral Residues: coffee husks (CH), potassium feldspar (PF), and Bahia Beige marble (BB) as reinforcements. Mechanical, thermal, and morphological characterizations were carried out, and a simplex–lattice mixture design was applied to optimize the formulations. The 70/20/5/5 (TPS/CH/PF/BB, wt.%) composition achieved the highest tensile strength (2.0 MPa) and elastic modulus (70.2 MPa), while the 90/0/5/5 formulation showed superior impact resistance. FTIR and SEM analyses confirmed effective filler dispersion and strong matrix–filler interactions. Scheffé polynomial models (R 2 > 87%) accurately predicted performance, highlighting the reliability of the statistical approach. From a sustainability perspective, this work demonstrates that upcycling coffee husks and mineral residues into TPS-based biocomposites contributes to waste reduction, landfill diversion, and the development of cost-effective biodegradable materials. The proposed systems offer potential for eco-friendly packaging and agricultural applications, reducing dependence on fossil-based plastics and mitigating the environmental footprint of polymer industries. Statistical optimization further enhances efficiency by minimizing experimental waste. Moreover, this research supports circular economy strategies and provides scalable, sustainable solutions for waste valorization.

Keywords: thermoplastic starch; sustainable composites; coffee husk; potassium feldspar; Bahia Beige marble; waste upcycling; circular economy; biodegradable materials; mechanical optimization (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2025
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