Resumen de Synthesis and caracterization of fluorinated polimers
The following doctoral thesis is focused on the field of thermoplastic polyurethanes (TPUs) and it is divided into two parts. The first deals with the synthesis of new fluorinated TPUs for the generation of hydrophobic materials with anti-staining properties that could be produced at an industrial scale at low cost. To fulfill this goal, trifluoroethanol (TFE) was selected as the main building block to generate difunctional monomers containing the trifluorethyl moiety in the backbone. The synthesis of five monomers was assessed, finally focusing on the most promising 3-(2,2,2-trifluoroethyoxy)-1,2-propanediol (DiolF), comprising the fluorinated group through a robust ether bond. Its production was scale-up to 2 kg in a reactor of 10 L, without the use of harmful solvents and with no loss of fluorine. In turn, DiolF was employed as the main monomer in several polymerization reactions to generate fluorinated polyester and polycaprolactones (PCLs) through different methodologies at a kilogram scale. A traditional polycondensation between acid adipic and DiolF lead to the desired product ADP:DiolF with high conversion of the monomers. Subsequently, DiolF was used as an initiator in a ringopening polymerization reaction with ¿-caprolactone.
Finally, two families of aliphatic TPUs, one based on PCL as the soft segment and another on polycarbonate were produced to test the role of fluorine. A total of 12 TPUs were characterized by optical, thermal, tribological, and surface properties. In addition to study various classes of polyols, several halogen contents were essayed (from 1.9 to 7.0 wt.% fluorine) by blending different ratios of ADP:DiolF in the TPU. Although diverse conditions were assessed, no significant improvements in water contact angle, surface free energy, or friction measurements were obtained. The combination of a highly compatible fluorinated polyester with the rest of the TPU matrix and rapid quenching of the material in the injection molding leads to a system that hampers the fluorine migration to the surface.
Concerning the second part of this research, it was focused on the development of control processes to produce a new TPU in continuous at Lubrizol facilities with reproducible quality.
Several variables such as the raw materials, reaction intermediates, the final polymer, and the posterior extruded film, were explored as a part of an exhaustive and large-scale study of the company
