SIGMALab SIGMALab Sustainability, Innovation, Green chemistry and Materials

PRIN - Projects of Relevant National Interest | P2022K9XN3

PRIN 2022 PNRR institutional project header

This project addresses the critical challenges of the ecological transition within the plastics sector, specifically focusing on cross-linked polymeric materials such as thermosetting resins and elastomers (rubbers). Due to their inherent chemical structure, these materials are typically infusible and insoluble, resulting in a current lack of sustainable end-of-life options. The strategic objective of the project is the development of a new generation of bio-based materials designed for the circular economy and chemical recycling (catalytic depolymerization), enabling the recovery of the original monomers at the end of their lifecycle.

Research and Development Lines

Scientific activities focus on the synthesis of innovative materials from renewable sources, with a particular emphasis on polylactic acid (PLA) and macrolactones. The core of the research involves the engineering of dynamic polymeric networks, such as vitrimeric systems and networks with reversible disulfide bonds. These chemical architectures allow the combination of high thermo-mechanical performance, typical of traditional materials, with the novel ability to be thermally reprocessed, repaired, and chemically recycled.

In parallel, the research extends to the development of high-performance eco-compatible composites ("green composites"). These materials are produced by integrating the new polymeric matrices with natural fibers and fillers derived from agricultural, industrial, and marine waste, including Posidonia oceanica, Ailanthus altissima, and keratin.

Main Scientific Objectives

  • Sustainable Synthesis: Development of thermosetting resins and elastomers based on degradable, bio-based aliphatic polyesters.
  • Thermoelastomer Design: Engineering of degradable ABA triblock copolymers capable of matching the performance of commercial rubbers while ensuring full recyclability.
  • Circular Economy: Validation of chemical recycling protocols to recover starting monomers, thereby eliminating the environmental impact of landfill disposal.
  • Waste Valorization: Production of reinforced polymeric composites through the recovery and high-value utilization of natural organic waste.

Consortium and Research Units

The project is implemented through the strategic synergy of three highly specialized Research Units:

  • University of Salerno (UNISA) - Coordinating Unit: Led by the Principal Investigator (PI), Prof. Claudio Pellecchia, with the participation of Prof. Mina Mazzeo. The unit coordinates the consortium's activities and leads the synthesis of PLA prepolymers, the development of vitrimeric thermosets, and the optimization of depolymerization processes.
  • University of Sannio (UNISANNIO): Led by Associated PI Prof. Daniela Pappalardo. This unit specializes in the synthesis of polyesters from renewable sources and focuses on the development of innovative elastomers with reversible polymeric networks.
  • University of Palermo (UNIPA): Led by Associated PI Prof. Roberto Scaffaro. The unit is responsible for the physico-chemical, rheological, and mechanical characterization of the synthesized materials, as well as the preparation, optimization, and degradation testing of composites reinforced with natural waste.
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Scientific Contribution of SIGMALab Group

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Publications

2026
Journal of Catalysis

Efficiency and synergy of bis-urea anions for the polymerization of cyclic esters

Riccardo Piacquadio, Federica Santulli, Michele Polise, Filomena L. Damiani, Stefano Milione, Marina Lamberti, Christophe M. Thomas, Consiglia Tedesco, Mina Mazzeo.

Graphical abstract for the Journal of Catalysis publication

Organocatalytic ring-opening polymerization of lactones is a highly versatile approach to obtain well-defined, biodegradable polyesters. Despite its sustainability advantages, a major challenge remains achieving both high activity and precise control over polymerization, particularly at low catalyst loadings. Here we report that bisurea anions, in the presence of an alcohol, are excellent catalysts for the ring-opening polymerization of lactide and various lactones. These catalytic systems exhibit "living/immortal" polymerization behavior, producing high molecular weight polymers with exceptional turnover frequencies (up to 250,000 h-1) even at catalyst loadings as low as 0.06%. Density functional theory calculations, supported by X-ray characterization, confirm the remarkable catalytic performance arises from synergistic interactions between urea moieties, which facilitate cooperative activation of the monomer. These interactions are further enhanced by metal-ion templating effects and the conformational flexibility of alkyl linkers, collectively contributing to the remarkable efficiency and control of the polymerization process.

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2025
Sustainable Materials and Technologies

3D wet-electrospun "branch leaf" graphene oxide polycaprolactone fibers structure for enhancing oil-water separation treatment performance in a multi-scale design

Roberto Scaffaro, Michele Gammino.

Graphical abstract for the Sustainable Materials and Technologies publication

Super-wetting materials have garnered significant attention for the potential to treat oily wastewater due to their selective adsorption and recyclability. In this work, we developed a hierarchical structure of polycaprolactone decorated with branch leaf-like graphene oxide (PCLGO) by wet-electrospinning process. This structure combines a hydrophilic/oleophobic GO anchored into an oleophilic/hydrophobic PCL 3D fiber network. The unique configuration ensures exceptional water diffusion due to the hydrophilic nature of GO, while the hydrophobic PCL fibers enhance the interaction with oil droplets. This synergy promotes oil spreading on the surface and enables superior phase separation of pollutants. The resulting PCLGO structures perform remarkably in separating both water-floating oil and oil-in-water emulsions, achieving an oil adsorption capacity (Qmax) of 28 g/g and an impressive separation efficiency of 99.8 %, with excellent recycling capacity up to 20 cycles. This study provides valuable insights into developing advanced multifunctional materials for water treatment applications and offers a potentially innovative strategy for addressing water treatment challenges.

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2025
Polymer Degradation and Stability

Photochemical degradation of PLA-based green composites containing waste biomass from Posidonia oceanica, Chamaerops humilis and Ailanthus altissima: A comparative study

Andrea Maio, Emmanuel F. Gulino, Michele Gammino, Maria Clara Citarrella, Roberto Scaffaro.

The photochemical degradability of PLA-based composites containing three different natural fillers, namely Posidonia oceanica (PO), Chamaerops humilis (CH), and Ailanthus altissima (AA), was evaluated to understand how the morphological and physicochemical features of these composite systems affect their durability. Composites containing 10% or 20% of filler were prepared by melt-processing and subjected to accelerated weathering involving UV irradiation and condensation cycles. The materials were thoroughly characterized, and the evolution of morphological, physicochemical, and mechanical properties was monitored upon aging time. The results demonstrate the significant impact of filler type on the photochemical stability of PLA-based composites. PO and CH fillers, with high porosity, resulted in less compact composites that underwent rapid hydrolytic degradation, experiencing surface and bulk erosion. AA composites exhibited the highest durability, with their dense morphology effectively delaying degradation. Overall, composites with 10% PO and 20% CH had the lowest stability (less than 6 h), the other PO- and CH-series materials retained durability for 24-30 h, similar to neat PLA, while AA-series composites proved to retain their mechanical properties for up to 36 h.

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2024
Advances in Polymer Technology

Effect of keratin waste on poly(epsilon-caprolactone) films: Structural characterization, thermal properties, and keratinocytes viability and proliferation studies

Gianluca Rinaldi, Elena Coccia, Nancy Ferrentino, Chiara Germinario, Celestino Grifa, Marina Paolucci, Daniela Pappalardo.

Keratin extracted (KE) from chicken feathers was used for the production of composite films comprising poly(epsilon-caprolactone) (PCL) and keratin (PCL/KE films). The process involved the extraction of keratin from chicken feathers using a 0.1 M NaOH solution, followed by characterization via sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The PCL was synthesized through the ring-opening polymerization (ROP) of epsilon-caprolactone (alpha-CL) with Sn(Oct)2 as a catalyst. Films were prepared via solvent casting, including pure PCL films and those enriched with different weight percentages of KE (10%, 15%, 25%, and 30%). The films were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TG), and scanning electron microscopy (SEM). SEM analysis revealed a more uniform incorporation of KE within the PCL matrix in the case of the 15% keratin-enriched film (PCL/KE15) as compared to other keratin percentages. The thermal analysis showed a positive influence of keratin on the thermal stability of the films. Keratinocytes viability and proliferation tests on the PCL/KE15 film demonstrated compatibility with cells. Collectively, these results hold relevance for potential biomedical applications of PCL/KE films.

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Posters

Conference contributions

Oral communication

Bio-based vitrimeric thermosets from polylactide and isosorbide diepoxide

Gaeta, L., Gentile, M., Tagoe, J. N. A., Gammino, M., Scaffaro, R., Pellecchia, C. Dynamic Polymer Networks meeting, Reykjavik, Iceland, August 11-14, 2025.

Oral communication

Synthesis and chemical recycling of sustainable polymeric materials derived from cyclic esters

C. Pellecchia et al. ACS Spring Meeting 2025, San Diego, United States, March 22-27, 2025.

Oral communication

Synthesis of PLA-based thermoplastic elastomers and thermosets

G. Gravina et al. EPF European Polymer Congress, Groningen, Netherlands, June 22-27, 2025.

Poster presentation

Organocatalytic synthesis of bio-based thermoplastic polyester elastomers

Piacquadio, R., Santulli, F., Lamberti, M., Mazzeo, M. Polymerisation and depolymerisation chemistry: the second century Faraday Discussion, Oxford, United Kingdom, September 8-10, 2025.

Poster presentation

Structural modifications and keratin integration in polybutylene succinate for sustainable advanced materials

Rinaldi, G., Russo, S., Paolucci, M., Pappalardo, D. Workshop on Sustainable Polymers and Circular Economy of Plastics (SusChem 2024), Ischia, Italy, September 1-4, 2024.

Poster presentation

Recyclable thermosetting materials from renewable sources: Synthesis and characterization of PLA-based thermosets

Gaeta, L., Pace, A., Pellecchia, C. Workshop on Sustainable Polymers and Circular Economy of Plastics (SusChem 2024), Ischia, Italy, September 1-4, 2024.

Poster presentation

Is it possible to obtain thermosetting materials from renewable sources which can be recycled at the end of their life?

Gaeta, L., Pace, A., Pellecchia, C. SYNC 2024, Symposium for Young Chemists, Rome, Italy, June 24-28, 2024.

Seminar

Sustainable polymeric materials and chemical recycling

Seminar by the PI Claudio Pellecchia at Stanford University, March 28, 2025.