Nuevas estrategias para reducir la migración de plastificantes en PVC

Resumen

In the frame of this PhD work three different strategies in order to reduce the migration of DOP in the PVC articles have been studied: the creation of coatings based on hybrid materials, the formation of a barrier by chemical modification on the sur faces and finally the substitution of classical DOP by new plasticizers which are chemically attached into the polymeric matrix. Related to the application of coatings based on organic-inorganic hybrid materials as a barrier for the additives, some preliminary works have been carried out. The sol-gel process has been in-line monitored by different spectroscopic techniques and these studies have contributed a mayor compression of the formation of these ceramers. The second approach was the cre ation of a barrier by wet-chemical modification and the following cross-linking process of the nano-modified layer on the surface of PVC. The studies have demonstrated that the diffusion process is lower than the reference system. This is probably du e to the dimensions of the created network, to the mesh size and mainly to the mechanical sensitivity of these thin layers. As possible solution we propose a change of experimental conditions, in which we can functionalize the surface in the micromet ric range, achieving therefore a higher thickness of the threedimensional network that they keep the additives into the polymer. The third studied strategy was the internal plasticization. It have been developed a versatile synthetic route that allo wed us the preparation of a new family of functionalized plasticizers based on DOP with mercapto groups. By using this chemical modification we have obtained new plasticized copolymers with high concentrations of additives, in which the graft plastic izer did not have any possibility to migrate from the polymeric matrix. It is important to remark, despite the grafting by covalent bonds, that the final material exhibits an efficient plasticization. So these new plastificizers are a promising alter native in order to avoid the associated problem to the migration of the classical plasticizers. Due to the possible industrial success of the new materials a patent has been deposited.