The internal plasticization of PVC by displacement of chlorine with phthalate-based thiol additives, that is, the covalent attachment of the plasticizer to the PVC chain, is described for the first time. Using this methodology, a good plasticization efficiency is achieved although flexibility is reduced compared with that of commercial PVC-phthalate systems. However, the migration is completely suppressed. This approach may open new ways to the preparation of flexible PVC with permanent plasticizer effect and zero migration.

No abstract

No abstract

The chemical modification of PVC films with sodium azide and 4-aminothiophenol was investigated. Using mixtures of a good and a nonsolvent for PVC, reactions took place in a controlled way, and the films remained transparent and smooth. To obtain information about the surface selectivity of the reactions, the degree of modification of the polymer across the film was determined by depth profiling carried out using confocal Raman microscopy. It is shown that the reaction with sodium azide always occurs homogeneously through the film while in the case of aminothiophenol, conditions could be found that allowed the polymer film to be preferentially modified at the surface. The gradient of the degree of modification and the surface selectivity depend on the relationship between the rate constants of the substitution reaction and the diffusion process of the reactant. They are, therefore, functions of reaction time, temperature, and the proportion of solvent/nonsolvent used for the reaction. The measured depth profiles as a function of reaction time have been fitted to a solution of the second Fickian law and combined diffusion/reaction coefficients for the transport of the reactant have been calculated.

A synthetic approach for the preparation and linkage of functionalized plasticizer molecules to PVC is described. The synthesis of this four-step procedure is economically and ecologically viable because it is based on trichlorotriazine as inexpensive starting material; the reactions can be carried out one-pot with quantitative yields and without need of final purification of the products. The approach is furthermore highly versatile and allows for the preparation of a large number of different plasticizers with properties that may be adjusted to a broad range of applications from highly flexible to semirigid.