Method for Photopolymerization 3D Printing of Recyclable Thermoplastic Polymers
Conventional light-based processes used in additive manufacturing (AM), such as vat polymerization, yield non-recyclable thermoset polymers, which pose sustainability issues at scale. This thesis studies a method for photopolymerization 3D printing of the common polymers polyacrylonitrile (PAN) and...
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| Format: | Disertacija |
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Massachusetts Institute of Technology
2024
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| Online pristup: | https://hdl.handle.net/1721.1/155850 https://orcid.org/0000-0002-5128-0503 |
| _version_ | 1826210019028238336 |
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| author | Tumkur Mahesh, Prajwal |
| author2 | Hart, A. John |
| author_facet | Hart, A. John Tumkur Mahesh, Prajwal |
| author_sort | Tumkur Mahesh, Prajwal |
| collection | MIT |
| description | Conventional light-based processes used in additive manufacturing (AM), such as vat polymerization, yield non-recyclable thermoset polymers, which pose sustainability issues at scale. This thesis studies a method for photopolymerization 3D printing of the common polymers polyacrylonitrile (PAN) and polymethyl methacrylate (PMMA) to address the growing demand for low-waste production of high-resolution polymer parts with complex geometries in industrial-scale manufacturing. This new approach not only produces directly recyclable linear thermoplastic polymers but also enables the light-based printing of polymers soluble in their own monomer.
It was previously demonstrated by Chazot et al. that photo-defined layers of polyacrylonitrile (PAN) can be formed at a liquid-liquid interface; this technique was named interfacial photopolymerization (IPP). In this thesis, which focuses on multilayer 3D printing (3D-IPP), the resolution and stability of layers formed by IPP are improved using a light-absorbing dye while incorporating a water-soluble polyethylene glycol binder to improve yield, printing speed, and mechanical properties. Joint initiation using commercial water-soluble photoinitiators V-50 and LAP, along with the addition of HCL and CaCl2, further enhances printing performance by producing dense layers and reducing voids. Post-processing techniques are devised to preserve part geometry after printing, including controlled air drying, thermal post-processing with PEG infiltration, and the inclusion of compatible polymeric binders in the printing composition to minimize cracking and shrinkage. Additionally, hardware is developed to integrate the IPP process into a commercial projector-based 3D printer, demonstrating compatibility of the proposed chemistry with off-the-shelf hardware. The capability to digitally manufacture high resolution 3D structures with IPP is demonstrated and the physical properties of the resulting composite polymer are characterized. While 3D-IPP cannot yet directly rival conventional manufacturing methods, the benign aqueous chemistry as well as recyclability and circularity of produced parts offers a promising path towards sustainable and resource-efficient AM as the technology matures. |
| first_indexed | 2024-09-23T14:39:56Z |
| format | Thesis |
| id | mit-1721.1/155850 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T14:39:56Z |
| publishDate | 2024 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/1558502024-08-02T03:16:38Z Method for Photopolymerization 3D Printing of Recyclable Thermoplastic Polymers Tumkur Mahesh, Prajwal Hart, A. John Massachusetts Institute of Technology. Department of Mechanical Engineering Conventional light-based processes used in additive manufacturing (AM), such as vat polymerization, yield non-recyclable thermoset polymers, which pose sustainability issues at scale. This thesis studies a method for photopolymerization 3D printing of the common polymers polyacrylonitrile (PAN) and polymethyl methacrylate (PMMA) to address the growing demand for low-waste production of high-resolution polymer parts with complex geometries in industrial-scale manufacturing. This new approach not only produces directly recyclable linear thermoplastic polymers but also enables the light-based printing of polymers soluble in their own monomer. It was previously demonstrated by Chazot et al. that photo-defined layers of polyacrylonitrile (PAN) can be formed at a liquid-liquid interface; this technique was named interfacial photopolymerization (IPP). In this thesis, which focuses on multilayer 3D printing (3D-IPP), the resolution and stability of layers formed by IPP are improved using a light-absorbing dye while incorporating a water-soluble polyethylene glycol binder to improve yield, printing speed, and mechanical properties. Joint initiation using commercial water-soluble photoinitiators V-50 and LAP, along with the addition of HCL and CaCl2, further enhances printing performance by producing dense layers and reducing voids. Post-processing techniques are devised to preserve part geometry after printing, including controlled air drying, thermal post-processing with PEG infiltration, and the inclusion of compatible polymeric binders in the printing composition to minimize cracking and shrinkage. Additionally, hardware is developed to integrate the IPP process into a commercial projector-based 3D printer, demonstrating compatibility of the proposed chemistry with off-the-shelf hardware. The capability to digitally manufacture high resolution 3D structures with IPP is demonstrated and the physical properties of the resulting composite polymer are characterized. While 3D-IPP cannot yet directly rival conventional manufacturing methods, the benign aqueous chemistry as well as recyclability and circularity of produced parts offers a promising path towards sustainable and resource-efficient AM as the technology matures. S.M. 2024-08-01T19:01:07Z 2024-08-01T19:01:07Z 2024-05 2024-06-13T16:49:12.086Z Thesis https://hdl.handle.net/1721.1/155850 https://orcid.org/0000-0002-5128-0503 Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) Copyright retained by author(s) https://creativecommons.org/licenses/by-sa/4.0/ application/pdf Massachusetts Institute of Technology |
| spellingShingle | Tumkur Mahesh, Prajwal Method for Photopolymerization 3D Printing of Recyclable Thermoplastic Polymers |
| title | Method for Photopolymerization 3D Printing of Recyclable Thermoplastic Polymers |
| title_full | Method for Photopolymerization 3D Printing of Recyclable Thermoplastic Polymers |
| title_fullStr | Method for Photopolymerization 3D Printing of Recyclable Thermoplastic Polymers |
| title_full_unstemmed | Method for Photopolymerization 3D Printing of Recyclable Thermoplastic Polymers |
| title_short | Method for Photopolymerization 3D Printing of Recyclable Thermoplastic Polymers |
| title_sort | method for photopolymerization 3d printing of recyclable thermoplastic polymers |
| url | https://hdl.handle.net/1721.1/155850 https://orcid.org/0000-0002-5128-0503 |
| work_keys_str_mv | AT tumkurmaheshprajwal methodforphotopolymerization3dprintingofrecyclablethermoplasticpolymers |