Synthesis of Biobased Polymers derived from Terpenes
- Autores: Leticia Peña Carrodeguas
- Directores de la Tesis: Arjan Kleij (dir. tes.)
- Lectura: En la Universitat Rovira i Virgili ( España ) en 2017
- Idioma: español
- Tribunal Calificador de la Tesis: Alexandr Shafir (presid.), Christophe Detrembleur (secret.), Michael P. Shaver (voc.)
- Programa de doctorado: Programa de Doctorado en Ciencia y Tecnología Química por la Universidad Rovira i Virgili
- Materias:
- Enlaces
- Tesis en acceso abierto en: hdl.handle.net TDX
- Resumen
The main purpose of this thesis is the synthesis of polycarbonates and polyesters based on renewable sources and the development of precursors based on fatty acids for the preparation of non-isocyanates polyurethanes.
In Chapter 1: Amino-triphenolate derived Al III complexes combined with suitable nucleophiles have been investigated as binary catalysts for the coupling of limonene oxide and carbon dioxide to afford alternating polycarbonates. These catalysts are able to produce stereoregular, perfectly alternating trans polymers from cis limonene oxide, whereas the pure trans isomer and cis/trans mixture give rise to lower degrees of stereoregularity. The best Al III catalyst shows the potential to mediate the conversion of both stereoisomers of limonene oxide with high conversion levels of up to 71% under neat conditions, indicating the high degree of robustness and atom-efficiency of this catalytic process. Computational studies have revealed unique features of the binary catalyst system, among which is the preferred nucleophilic attack on the quaternary carbon centre in the limonene oxide substrate.
In Chapter 2: Semi-renewable aliphatic polyester have been synthesized. Renewable, biodegradable polymers, such as aliphatic polyesters, based on sustainable sources have attracted considerable interest as alternatives to petroleum-based polymers. One limiting factor in the development of aliphatic polyesters as replacements for these materials has been their relatively low glass transition temperatures (Tg). For example, commercially available poly(lactic acid) has a Tg of approximately 60 °C. Epoxide/anhydride copolymerizations offer an alternative to the ring- opening polymerization of lactones for the synthesis of aliphatic polyesters and allow for tuning of polymer properties through two distinct monomer sets. We synthesized six partially or fully renewable tricyclic anhydrides and copolymerized them with propylene oxide (PO) and cyclohexene oxide (CHO). By varying both the epoxide and the anhydride, we were able to tune the Tg of the resulting polymers over a nearly 120 °C range from 66 °C to an exceptionally high 184 °C. Polymers produced with PO had a lower range of Tg values (66−108 °C) and higher molecular weights up to 32.2 kDa, while those produced with CHO had higher Tg values (124−184 °C) and lower molecular weights, showing the profound influence of both monomer sets. To the best of our knowledge, these are the highest Tg values reported for entirely aliphatic polyesters.
In Chapter 3: The formation of bio-derived materials is gaining momentum in academic and industrial laboratories, though the use of terpene oxides as renewable monomers for the preparation of bio-based polymers yet remains limited. In order to advance the impact of such monomers, we have investigated the use of terpene derived epoxides (limonene oxide, carene oxide, limonene dioxide and menthene oxide) for the ring-opening copolymerization (ROCOP) in the presence of various aromatic anhydrides. These copolymerization reactions were mostly performed under mild reaction conditions (65ºC, low loading of catalyst: 0.50 mol%) using a binary catalyst comprising of a Fe(III) based aminotriphenolate complex and PPNCl (bis(triphenylphosphine)iminium chloride) providing partially bio-based semi-aromatic polyesters with molecular weights of up to 25 Kg/mol (Ð = 1.54) and glass transitions spanning a wide range from 59 to 243 ºC. The copolymerization reactions proceed with excellent selectivity towards fully alternating polyesters with modular thermal properties that depend on the nature of the terpene oxide used, and are potentially useful towards the development of new coating and thermoset materials.
In Chapter 4: A catalytic method for the preparation of a series of fatty acid derived biocarbonates has been developed using a binary Al-complex/PPNCl catalyst. This catalyst system allows to convert the fatty acid derived epoxides under comparatively mild reaction conditions (70‒85 ºC, 10 bar) while maintaining high levels of diastereospecificity with cis/trans ratios in the products of up to 97:3. Comparative catalysis data obtained for the reactions catalysed only by the nucleophilic halide based components shows that the presence of the Al-complex is crucial for retention of the original stereochemistry.
