Periodic Reporting for period 1 - SUSTAINABLE (Library of inedited bio-based multicomponent resins for the 3D-printing of self-healing, recyclable thermosets.)
Periodo di rendicontazione: 2021-09-20 al 2023-09-19
With the increasing concerns on the environmental issues and the depletion of fossil-based resources, the production of plastics according with the conventional approaches, chemistry and technologies is not feasible anymore. Innovative and sustainable approaches for the development of these irreplaceable materials are, therefore, strongly demanded. To reach this aim, aspects, such as the environmental impact of the starting resources, the production technologies and the end of life managements (i.e. recyclability or biodegradability), need to be carefully considered.
Plastics can be classified in two categories: thermoplastics and thermosets. Thermoplastics can be made to flow upon heating and thereby reprocessable by common melt-processing techniques. Thermosets on the other hand are chemically crosslinked structures, which makes thermal reprocessing impossible and causes additional challenge for chemical recycling. The main aim of SUSTAINABLE is to develop 3D biobased, self-healable, recyclable thermosets starting from natural resources and employing a light-driven 3D printing technology, called digital light processing 3D printing (DLP). The results of this project can make an impact for the society since they will contribute to the reduction of the consumption of the fossil-based resources as well as to the introduction of new chemistries for the development of recyclable thermosets, contributing therefore to the overall reductions of the environmental issue related to the production of conventional thermosets. Moreover, DLP is preferred to thermally-driven 3D printing technologies, due to the higher efficiency of the light polymerization approaches. The project has reached the following objectives: Design and development of a library of molecules (called resins) suitable for the synthesis of biobased, recyclable and self-healable thermosets; DLP of the resins in form of tridimensional thermosets and their characterizations also in terms of recyclability and self-healing; to educate the researcher on the development of bio-based photopolymerizable resins as well as to the management of the scientific project.
Plastics can be classified in two categories: thermoplastics and thermosets. Thermoplastics can be made to flow upon heating and thereby reprocessable by common melt-processing techniques. Thermosets on the other hand are chemically crosslinked structures, which makes thermal reprocessing impossible and causes additional challenge for chemical recycling. The main aim of SUSTAINABLE is to develop 3D biobased, self-healable, recyclable thermosets starting from natural resources and employing a light-driven 3D printing technology, called digital light processing 3D printing (DLP). The results of this project can make an impact for the society since they will contribute to the reduction of the consumption of the fossil-based resources as well as to the introduction of new chemistries for the development of recyclable thermosets, contributing therefore to the overall reductions of the environmental issue related to the production of conventional thermosets. Moreover, DLP is preferred to thermally-driven 3D printing technologies, due to the higher efficiency of the light polymerization approaches. The project has reached the following objectives: Design and development of a library of molecules (called resins) suitable for the synthesis of biobased, recyclable and self-healable thermosets; DLP of the resins in form of tridimensional thermosets and their characterizations also in terms of recyclability and self-healing; to educate the researcher on the development of bio-based photopolymerizable resins as well as to the management of the scientific project.
The research work consisted in the following activities:
- Careful investigation of the state of the art on the approaches for the combination of biobased molecules with dynamic covalent bonds. These activities have led to the publication of a scientific review with title “Designed from Biobased Materials for Recycling: Imine-Based Covalent Adaptable Networks” in Macromolecular Rapid Communications.
- Design for circularity of vanillin-based photocurable resin by incorporation of imine functionalities. The thermoset expressed malleability, self-healing and thermal reprocessability and it was chemically recycled. The suitability of the resin for the production of 3D objects by means of DLP was demonstrated. These activities have led to the publication of a scientific paper on European Polymer Journal.
- Development of bio-based and recyclable composite thermosets through DLP by dispersing cellulose-derived carbon dots (CDs) in a photocurable vanillin resin endowed with imine functions. The exposure of CDs to DLP induced the self-assembly of CDs into micrometric fibers embedded in the thermoset matrix. These activities have led to the publication of a scientific paper in Special number in Polymer.
- A study, focused on the investigation of the potential of a simple non-equilibrium atmospheric plasma post-treatment strategy for the surface coating of 3D structures produced by DLP, was carried out. The influence of non-equilibrium atmospheric plasma on the properties of vanillin-derived Schiff-base thermosets and the dip-coating process was investigated and compared to the influence of traditional post-treatment with UV-light. These activities have led to a scientific paper just accepted on ACS Applied Polymer Materials. To carry out these activities a plasma system was rented from AlmaPlasma srl for 10 months.
- Four isosorbide-based photocurable resins were designed to reveal correlations between the composition and chemical structure, printability, thermoset properties and recyclability. The work is the result of a collaboration with the Group of Prof. Marco Sangermano from Politecnico di Torino and it has led to the publication of a scientific paper on ACS Sustainable Chemistry and Engineering.
- Four ester- and ester-imine thermosets were obtained by the digital light processing 3D printing of bio-based resins and tested for reprocessing and biodegradation in composting conditions. The work is the result of a collaboration with the Group of Prof. Marek Kowalczuk from Centre of Polymer and Carbon Materials Polish Academy of Sciences. The manuscript is currently under preparation.
During the project, the researcher, Anna Liguori, attended instrumental training at KTH and she also attended the following two courses:
- Communicating Research beyond the Academy, 30 teaching hours, organized by ITM/Learning in Engineering Sciences at KTH.
- NMR Spectroscopy and imaging – basic principles, 30 teaching hours, organized by CBH/Chemistry at KTH
Moreover, Anna also attended seminars on topics related to the writing of successful proposal and on the ethical principles and the importance of equality and equity in the workplace.
During the period of the project, Anna also organized a seminar for the Division of Polymer Technology on the potential of plasma technology for the surface modification of the materials. The seminar was given by the Research Group on Industrial Applications of Plasma from University of Bologna.
The results of the project have been disseminated through: the writing and publication of scientific papers on international journals (3 papers have already been published, 2 papers have been accepted for publication, 1 paper is currently under preparation); Oral contributions in 3 scientific conferences (i.e. Nordic Polymer Days, Baltic BioMat, EUPOC2023); two workshops on the topics and results on the project given by the researcher to the Division of Polymer Technology; LinkedIn; Web page of the project.
- Careful investigation of the state of the art on the approaches for the combination of biobased molecules with dynamic covalent bonds. These activities have led to the publication of a scientific review with title “Designed from Biobased Materials for Recycling: Imine-Based Covalent Adaptable Networks” in Macromolecular Rapid Communications.
- Design for circularity of vanillin-based photocurable resin by incorporation of imine functionalities. The thermoset expressed malleability, self-healing and thermal reprocessability and it was chemically recycled. The suitability of the resin for the production of 3D objects by means of DLP was demonstrated. These activities have led to the publication of a scientific paper on European Polymer Journal.
- Development of bio-based and recyclable composite thermosets through DLP by dispersing cellulose-derived carbon dots (CDs) in a photocurable vanillin resin endowed with imine functions. The exposure of CDs to DLP induced the self-assembly of CDs into micrometric fibers embedded in the thermoset matrix. These activities have led to the publication of a scientific paper in Special number in Polymer.
- A study, focused on the investigation of the potential of a simple non-equilibrium atmospheric plasma post-treatment strategy for the surface coating of 3D structures produced by DLP, was carried out. The influence of non-equilibrium atmospheric plasma on the properties of vanillin-derived Schiff-base thermosets and the dip-coating process was investigated and compared to the influence of traditional post-treatment with UV-light. These activities have led to a scientific paper just accepted on ACS Applied Polymer Materials. To carry out these activities a plasma system was rented from AlmaPlasma srl for 10 months.
- Four isosorbide-based photocurable resins were designed to reveal correlations between the composition and chemical structure, printability, thermoset properties and recyclability. The work is the result of a collaboration with the Group of Prof. Marco Sangermano from Politecnico di Torino and it has led to the publication of a scientific paper on ACS Sustainable Chemistry and Engineering.
- Four ester- and ester-imine thermosets were obtained by the digital light processing 3D printing of bio-based resins and tested for reprocessing and biodegradation in composting conditions. The work is the result of a collaboration with the Group of Prof. Marek Kowalczuk from Centre of Polymer and Carbon Materials Polish Academy of Sciences. The manuscript is currently under preparation.
During the project, the researcher, Anna Liguori, attended instrumental training at KTH and she also attended the following two courses:
- Communicating Research beyond the Academy, 30 teaching hours, organized by ITM/Learning in Engineering Sciences at KTH.
- NMR Spectroscopy and imaging – basic principles, 30 teaching hours, organized by CBH/Chemistry at KTH
Moreover, Anna also attended seminars on topics related to the writing of successful proposal and on the ethical principles and the importance of equality and equity in the workplace.
During the period of the project, Anna also organized a seminar for the Division of Polymer Technology on the potential of plasma technology for the surface modification of the materials. The seminar was given by the Research Group on Industrial Applications of Plasma from University of Bologna.
The results of the project have been disseminated through: the writing and publication of scientific papers on international journals (3 papers have already been published, 2 papers have been accepted for publication, 1 paper is currently under preparation); Oral contributions in 3 scientific conferences (i.e. Nordic Polymer Days, Baltic BioMat, EUPOC2023); two workshops on the topics and results on the project given by the researcher to the Division of Polymer Technology; LinkedIn; Web page of the project.
The main progress beyond the state of the art of SUSTAINABLE is represented by the identification of possible strategies for the design of photocurable biobased resins suitable for the manufacturing of thermosets showing self-healing and recyclability. Another progress beyond the state of the art is represented by the design of a simple and effective approach for the functional coating of DLP thermosets. Moreover, the interest towards biobased and recyclable thermosets is also reaching forefront sectors, such as the field of tissue engineering. On this topic, the researcher, Anna Liguori, and her supervisor, Prof. Minna Hakkarainen, in collaboration with the Group of Prof. Diego Mantovani, University of Laval, Canada, submitted a proposal in the call “Initiation Grants for Internationalisation” promoted by STINT, The Swedish Foundation for International Cooperation in Research and Higher Education. The proposal was positively evaluated and financed. The activities are currently on-going and potential results are expected within the end of next years.