(Tetrahydro)furanic polymers from CO2 & biomass
Abstract/Contents
- Abstract
- Plastic materials are critical for modern technology and commerce, yet the environmental concerns surrounding plastic production and waste accumulation have inspired efforts to rethink how plastics are manufactured and managed at their end-of-use. Many of the challenges associated with plastic -- emissions-intensive production, limited recyclability, and environmental persistence -- are attributable to their petroleum-based monomers. Biomass is a renewable, abundant, and sustainable alternative feedstock from which to derive monomers, but to displace petroleum-derived plastics, new bio-derived polymers must be properly sourced, inexpensive to produce, and deliver equivalent or superior performance compared to existing materials. Polyesters based on furan dicarboxylic acids are among the most promising performance-advantaged bio-plastics because of their exceptional thermomechanical and gas barrier properties. The success of furan-based polyesters has inspired numerous investigations into other polymers with furan and tetrahydrofuran structures, hereafter referred to jointly as (tetrahydro)furanics. Previous investigations, however, almost exclusively focused on symmetric (tetrahydro)furanic monomers. Recent advances in furan derivatization, including the development of carbonate-mediated furan carboxylation with carbon dioxide (CO2), have enabled more efficient routes to asymmetric (tetrahydro)furanic monomers, thereby opening practical pathways to new (tetrahydro)furanic monomers and inspiring the reexamination of ones previously overlooked. This dissertation examines the structure-property relationships of polymers with asymmetric (tetrahydro)furanic backbones. Each polymer studied can be synthesized entirely from bio-derived compounds (e.g. furfural) and renewable small molecules (e.g. CO2, O2, H2, NH3). Chapter 1 provides an overview of the successes, failures, and future prospects of plastic. Further, it describes how furfural can play a key role in the production of more sustainable materials. In Chapter 2, a tetrahydrofuranic analog to nylon 6 is synthesized from a furfurylamine-derived bicyclic lactam and thermally characterized. The resulting polyamide, PITC, has a glass transition temperature (Tg) approximately 70 °C higher than that of standard nylon but also has a lower thermal decomposition temperature. When polymerized from both racemic and enantiopure lactam, PITC is amorphous. PITC is also more easily hydrolyzed than traditional nylon, making it readily chemically recyclable. In Chapter 3, a furan-based semi-aromatic polyamide (SAP), PAMF, is synthesized from a furfurylamine-derived amino acid. Two methods -- organic phosphite and direct solid-state polymerizations -- were developed to produce high molecular weight PAMF for the first time. Unlike most other furan-based SAPs, PAMF is semi-crystalline and has a high melting temperature (Tm). Molecular dynamics simulations suggest PAMF is semi-crystalline because of its unique intramolecular hydrogen bonding interactions that promote structural regularity. PAMF is readily copolymerizable with nylon 6 to yield SAPs with thermal properties (e.g. Tg and Tm) rivaling those of commercial petroleum-derived SAPs. In addition, PAMF is also shown to be easily chemically recycled through base-catalyzed hydrolysis. In Chapter 4, a tetrahydrofuran-based lactone, ODO, is synthesized and polymerized to PODO, an aliphatic polyester resembling poly(ε-caprolactone) (PCL). In comparison to PCL, PODO has a lower enthalpy of polymerization, faster rate of polymerization, higher Tg, and lower degradation temperature. Since PODO is synthesized from racemic ODO, homopolymeric PODO is an amorphous, low modulus material, but when copolymerized in small proportions with L-lactide (L-LA), the resulting copolymers are robust thermoplastics with identical modulus, slightly decreased glass transition temperatures, and up to 10× elongation at break compared to native poly(L-lactic acid). In Chapter 5, an asymmetric semi-aromatic polyester, PHMF, is synthesized and analyzed against phenyl and diacid-derived analogs using thermal, spectroscopic, and computational methods to elucidate structure-property relationships. Compared to diacid-derived polyesters, PHMF is more rigid and crystalline. Compared to phenyl-derived polyesters, PHMF is denser. Molecular dynamics supports experimental observations and suggests non-covalent intermolecular interactions from the furan ring enhance density. Further, PHMF is readily chemically recycled through methanolysis to recover monomer without extensive purification. Together, these examples demonstrate how overlooked asymmetric (tetrahydro)furanic moieties exhibit distinct properties from previously synthesized symmetric (tetrahydro)furanic polymers and petroleum-derived materials.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2024; ©2024 |
| Publication date | 2024; 2024 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Woroch, Cristián Pacheco |
|---|---|
| Degree supervisor | Kanan, Matthew |
| Thesis advisor | Kanan, Matthew |
| Thesis advisor | Waymouth, Robert |
| Thesis advisor | Xia, Yan |
| Degree committee member | Waymouth, Robert |
| Degree committee member | Xia, Yan |
| Associated with | Stanford University, School of Humanities and Sciences |
| Associated with | Stanford University, Department of Chemistry |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Cristián Pacheco Woroch. |
|---|---|
| Note | Submitted to the Department of Chemistry. |
| Thesis | Thesis Ph.D. Stanford University 2024. |
| Location | https://purl.stanford.edu/rb821fh4799 |
Access conditions
- Copyright
- © 2024 by Cristián Pacheco Woroch
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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