Tesis doctoral de Romina Marín Bernabé
The presented thesis is addressed to the development of polyurethanes made from carbohydrate derived diols. Polyurethanes are extremely versatile polymers that can be used in a wide variety of applications going from massive filling foams to highly technical items. The preparation of polyurethanes from renewable feedstocks is currently receiving increasing attention in the polyurethane industry. Diols derived from naturally-occurring fats and oils as well as biotechnologically produced diols like 1,3-propanediol and hydroxyl end-caped poly(lactic acid) have been recently introduced in the synthesis of these polymers. A fair number of polyurethanes containing units derived from saccharides have been reported so far although none of them has reached industrialization; the selection embraces polymers made from complex polyhydroxylated lignin fragments to cyclic diols such as isosorbide and gulonolactones. the thesis describes the preparation of linear polyurethanes from acyclic carbohydrate derived diols, specifically tartaric acid and alditols from tartaric acid, and arabino- and xylopyranose. Additionally, other natural diols from glucose but with cyclic structure, 1,4:3,6-dianhydrosorbitol and 2,4:3,5-di-o- methylene-d-glucitol were used. All diols used in this thesis are accessible via chemical synthesis or are directly commercially available, and therefore they are a good option to introduce natural products in the polyurethane chemistry. The incorporation of these hydrophilic units can also render polyurethanes more susceptible to hydrolysis. the first block of this thesis is dedicated to the synthesis, characterization and hydrodegradability of polyurethanes from alditols having all secondary hydroxyl groups protected as methyl ether, benzyl ether or acetal. Since total or partial splitting of the benzyl ethers or acetal groups after polymerization was feasible by hydrogenolysis or treatment by acids, respectively, these methods provided a suitable route to polyurethanes bearing pendant hydroxyl groups, which are highly hydrophilic and more susceptible to hydrolysis. the second block describes the synthesis of tartrate derived polyurethanes. In this case, tartrates were directly reacted with diisocyanates, and polyurethanes with different alkyl or benzyl ester side groups were obtained. The hydrodegradability of these polyurethanes was enhanced by incubating them in acid or basic buffers that hydrolysate the side alkyl esters, or by hydrogenolysis of the benzyl esters; in both cases polyurethanes bearing carboxylic side groups much more hydrolysable than their parent polyurethanes were prepared. the third block is dedicated to the study of segmented polyurethanes. Because there is a growing interest in introducing new chain extenders derived from renewable resources as an alternative to oil-based monomers, and also with the objective of enhancing the hydrodegradability of the resulting polyurethanes, two different carbohydrate derived monomers and their corresponding segmented polyurethanes were used as chain extenders in segmented polyurethanes with soft segment of polycaprolactone. finally, the last block is dedicated to the phenomenon of stereocomplexation. The preparation method, the formation, evidenced by different spectroscopic techniques, and crystallizability of a polytartaramide stereocomplex is described. In addition, the exploration of stereocomplexation in other systems is presented.
Datos académicos de la tesis doctoral «Carbohydrate-based polyurethanes and polyamides: synthesis, characterization and stereocomplex formation«
- Título de la tesis: Carbohydrate-based polyurethanes and polyamides: synthesis, characterization and stereocomplex formation
- Autor: Romina Marín Bernabé
- Universidad: Politécnica de catalunya
- Fecha de lectura de la tesis: 07/05/2009
Dirección y tribunal
- Director de la tesis
- Sebastián Muñoz Guerra
- Tribunal
- Presidente del tribunal: María Valpuesta fernández
- Jesús Santamaría (vocal)
- virginia Cádiz deleito (vocal)
- María violante De paz báñez (vocal)