Colouration of Blends of PVDF with Acrylic Polymers

摘要

Polyvinylidene and its copolymers ( VDF-HFP, VDF-CTFE) are known to possess very limited compatibility with colorants in particular with dyes in molecular form . Introduction of dyes into PVDF matrix is rapidly followed by migration of dye molecules onto polymer surface. The situation can be improved by application of compatible mixtures of PVDF with some polymers ( acrylic polymers, PVA, etc. ) having much better ability in terms of durable colouration. Tinted blend of PVDF with miscible polymer is obtained through dissolution in mutual solvent with adding colourant. Drying of coloured lacquer results in formation of coating of fair optical and tensile properties. From the thermodynamic point if view blend of PVDF and other polymer obtained through solution can be considered as solid solution without any phase separation. Increased compatibility of dyes with for example PVDF-PMMA solid solution is explained by dye molecules interaction with PMMA known to be very good matrix for many organic colourants. Usually introduction of 20 -40% of PMMA is enough to obtain reliable colouration of PVDF based compositions. However for certain types of colourants mentioned above approach appeared to be unsuitable. These are photo-luminescent dyes (PhLD) which found the application in different optical active coatings.