Tuning the Polymer Structure for Intrinsic Coating Photostabilisation

Fluorinated groups can effectively improve the chemical, thermal, and photo-chemical stability of a polymeric material; in addition, they can strongly reduce its surface energy and modify its tribologic behaviour. Coatings based on fluoroolefin copolymers are, however, unsuitable for many end uses, where the processing or application conditions and the requirements of adhesion, thermal and mechanical properties can not be matched by the available products. Fluorinated polymers based on modified urethanes, alkyds, vinyl ethers, silicones and acrylics can be successfully employed, although their partially fluorinated structure does not generally grant a performance comparable with that of most fluoroolefin copolymers in terms of chemical stability and, therefore, service durability. The comparative study of the photochemical stability and surface properties of a series of copolymers of fluorinated acrylates with unfluorinated acrylates and alkenyl ethers has allowed us to achieve improved intrinsic photostabilisation through control on the copolymer structure. According to the adopted systematic approach, fluorinated copolymers based on 2-fluoroacrylates and their unfluorinated analogues are tested under accelerated photoageing conditions; stepwise modification of the polymeric structure is then carried out according to the obtained results.