Preparation of Polymeric Ultraviolet Stabilizers

A consideration of conventional ultraviolet stabilizers used to prevent or retard the photooxidation of organic polymers, shows that overall effectiveness is often severely limited by poor long-term performance. This is not, in general, a result of photodecomposition of the stabilizer, but rather of physical loss of the stabilizer from the matrix polymer through diffusion, through extraction or through phase separation processes. The solubility of the stabilizer in the matrix is often less than the minimum effective concentration, leading to stabilizer migration, and exposure to solvents and/or high temperatures in processing or in use can accelerate stabilizer loss. These problems are particularly acute in the stabilization of thin films and coatings.