Of Uv Absorbers On The Stabilizing Effect Of Polymer Light Ree Chemical Modification Study

Rare earth complexation improvement effects of rare earth complexes of UV absorber "Dibenzoylmethan(HDBM),l-Benzoylacetone(HBA),2-hydroxy-4-octoxyl-benzophenone(HOB P)and2-hydroxy-4-meth-oxyl-benzophenone(HMBP)"have been studied, and photo-stabilization efficiency of rare earth complexes of UV absorber together with light stabilizer 770, NBC. 2002 or 1084 are also tested. At last photo-stabilization mechanism of rare earth complexes of UV absorber have been discussed by theory and mechanic experiments. The main results and conclusion are:(1) The test of photo-stabilization to polymer of rare earth complexes of UV absorber have been made in laboratory accelerate experiment, results show that by forming rare earth complexes can improve the photo-stabilization efficiency to polymer of UV absorber remarkably, except the La Gd, Lu . Y, Sc complexes, while for same UV absorber, the improve effect changed regularly as "Four Groups Effect" with the increase sf the atomic number of rare earth elements.(2) Meanwhile, rare earth complexes of UV absorber show confrontation effect when mixed with light stabilizer NBC, but all the rare earth complexes of UV absorber show coordination effect when mixed with light stabilizer 770, 2002 or 1084. For the same rare earth ion. the coordination effect is 770 -~ 1084 > 2002 > NBC The coordination effect of UV absorbers with other light stabilizers is larger than their rare earth complexes, but it becomes small when UV absorbers with light stabilizer NBC.(3) Photo-stabilization mechanisms of rare earth complexes of UV absorber are pointed by experiments and theory analysis. Rare earth complexes can coordinate with light - sensitive radicals (hydroperoxide or carbonyl et al) in the polymers using the supernumerary coordination valence. As a result, quenching excited-state ability of UV absorbers can be improved effectively. Since the quenching excited-state process is irrelevant to optical path, rare earth complexes of UV absorber can overcome the disadvange of protecting the surface of products and thin products.