Valorization of Tomato Stem Waste: Biochar as a Filler in Three-Dimensional Printed PLA Composites

Dimitrios Gkiliopoulos; Sotirios Pemas; Stylianos Torofias; Konstantinos Triantafyllidis; Dimitrios N. Bikiaris; Zoi Terzopoulou; Eleftheria Maria Pechlivani

doi:10.3390/polym17192565

Valorization of Tomato Stem Waste: Biochar as a Filler in Three-Dimensional Printed PLA Composites

Dimitrios Gkiliopoulos, Sotirios Pemas, Stylianos Torofias, Konstantinos Triantafyllidis, Dimitrios N. Bikiaris, Zoi Terzopoulou^*, Eleftheria Maria Pechlivani^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

Abstract

This study explores the valorization of tomato stem waste by converting it into biochar through slow pyrolysis and incorporating it into poly(lactic acid) (PLA) composites for fused filament fabrication (FFF) 3D printing. The objective was to improve the valorization and added value of tomato stem waste. Biochar derived from tomato stems was characterized for its physicochemical properties, revealing a high surface area and small particle size. PLA-based composite filaments with 5% and 7.5% biochar were manufactured via melt extrusion. The effects of biochar concentration and printing infill patterns (concentric and rectilinear) on the mechanical and thermomechanical properties of the 3D-printed composites were investigated. Results indicated that biochar slightly increased the glass transition temperature of PLA and improved the flexural properties. Dynamic mechanical analysis (DMA) showed that the storage modulus was enhanced in the glassy region for composites with 5% biochar, suggesting improved stiffness. This research demonstrates the potential of using tomato stem-derived biochar as a sustainable filler in PLA composites, contributing to the circular economy and reducing environmental impact.

Original language	English
Article number	2565
Journal	Polymers
Volume	17
Issue number	19
DOIs	https://doi.org/10.3390/polym17192565
State	Published - Oct 2025

Bibliographical note

Publisher Copyright:
© 2025 by the authors.

Keywords

3D printing
additive manufacturing
agricultural waste
biobased composites
biochar
circular economy
composite filament
fused deposition modeling (FDM)
poly(lactic acid)
pyrolysis

ASJC Scopus subject areas

General Chemistry
Polymers and Plastics

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.3390/polym17192565

Cite this

@article{21a15669cbcd4a2aad9e99841a9db7cf,

title = "Valorization of Tomato Stem Waste: Biochar as a Filler in Three-Dimensional Printed PLA Composites",

abstract = "This study explores the valorization of tomato stem waste by converting it into biochar through slow pyrolysis and incorporating it into poly(lactic acid) (PLA) composites for fused filament fabrication (FFF) 3D printing. The objective was to improve the valorization and added value of tomato stem waste. Biochar derived from tomato stems was characterized for its physicochemical properties, revealing a high surface area and small particle size. PLA-based composite filaments with 5\% and 7.5\% biochar were manufactured via melt extrusion. The effects of biochar concentration and printing infill patterns (concentric and rectilinear) on the mechanical and thermomechanical properties of the 3D-printed composites were investigated. Results indicated that biochar slightly increased the glass transition temperature of PLA and improved the flexural properties. Dynamic mechanical analysis (DMA) showed that the storage modulus was enhanced in the glassy region for composites with 5\% biochar, suggesting improved stiffness. This research demonstrates the potential of using tomato stem-derived biochar as a sustainable filler in PLA composites, contributing to the circular economy and reducing environmental impact.",

keywords = "3D printing, additive manufacturing, agricultural waste, biobased composites, biochar, circular economy, composite filament, fused deposition modeling (FDM), poly(lactic acid), pyrolysis",

author = "Dimitrios Gkiliopoulos and Sotirios Pemas and Stylianos Torofias and Konstantinos Triantafyllidis and Bikiaris, \{Dimitrios N.\} and Zoi Terzopoulou and Pechlivani, \{Eleftheria Maria\}",

note = "Publisher Copyright: {\textcopyright} 2025 by the authors.",

year = "2025",

month = oct,

doi = "10.3390/polym17192565",

language = "English",

volume = "17",

journal = "Polymers",

issn = "2073-4360",

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T2 - Biochar as a Filler in Three-Dimensional Printed PLA Composites

AU - Gkiliopoulos, Dimitrios

AU - Pemas, Sotirios

AU - Torofias, Stylianos

AU - Triantafyllidis, Konstantinos

AU - Bikiaris, Dimitrios N.

AU - Terzopoulou, Zoi

AU - Pechlivani, Eleftheria Maria

PY - 2025/10

Y1 - 2025/10

N2 - This study explores the valorization of tomato stem waste by converting it into biochar through slow pyrolysis and incorporating it into poly(lactic acid) (PLA) composites for fused filament fabrication (FFF) 3D printing. The objective was to improve the valorization and added value of tomato stem waste. Biochar derived from tomato stems was characterized for its physicochemical properties, revealing a high surface area and small particle size. PLA-based composite filaments with 5% and 7.5% biochar were manufactured via melt extrusion. The effects of biochar concentration and printing infill patterns (concentric and rectilinear) on the mechanical and thermomechanical properties of the 3D-printed composites were investigated. Results indicated that biochar slightly increased the glass transition temperature of PLA and improved the flexural properties. Dynamic mechanical analysis (DMA) showed that the storage modulus was enhanced in the glassy region for composites with 5% biochar, suggesting improved stiffness. This research demonstrates the potential of using tomato stem-derived biochar as a sustainable filler in PLA composites, contributing to the circular economy and reducing environmental impact.

AB - This study explores the valorization of tomato stem waste by converting it into biochar through slow pyrolysis and incorporating it into poly(lactic acid) (PLA) composites for fused filament fabrication (FFF) 3D printing. The objective was to improve the valorization and added value of tomato stem waste. Biochar derived from tomato stems was characterized for its physicochemical properties, revealing a high surface area and small particle size. PLA-based composite filaments with 5% and 7.5% biochar were manufactured via melt extrusion. The effects of biochar concentration and printing infill patterns (concentric and rectilinear) on the mechanical and thermomechanical properties of the 3D-printed composites were investigated. Results indicated that biochar slightly increased the glass transition temperature of PLA and improved the flexural properties. Dynamic mechanical analysis (DMA) showed that the storage modulus was enhanced in the glassy region for composites with 5% biochar, suggesting improved stiffness. This research demonstrates the potential of using tomato stem-derived biochar as a sustainable filler in PLA composites, contributing to the circular economy and reducing environmental impact.

KW - 3D printing

KW - additive manufacturing

KW - agricultural waste

KW - biobased composites

KW - biochar

KW - circular economy

KW - composite filament

KW - fused deposition modeling (FDM)

KW - poly(lactic acid)

KW - pyrolysis

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DO - 10.3390/polym17192565

M3 - Article

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VL - 17

JO - Polymers

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ER -

Valorization of Tomato Stem Waste: Biochar as a Filler in Three-Dimensional Printed PLA Composites

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

UN SDGs

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