Synthesis and properties of new UV-absorbers with higher MW

Abstract

Four new UV-absorbers with higher MW, 2-hydroxy-4-benzophenonyl n-octadecyl carbamate (A, MW = 509), 2-hydroxy-4-benzophenonyl hexamethylene dicarbamate (B, MW = 596), 2-hydoxy-4-benzophenonyl toluene 2,4 dicarbamate (C, MW = 602), and 2-hydroxy-4-benzophenonyl methylene diphenylene dicarbamate (D, MW = 678), have been synthesized by direct addition reaction of 2,4-dihydroxy benzophenone (DHBP) and isocyanates. The structures of these UV-absorbers have been characterized by IR, NMR, UV, MS and elemental analysis. The photostabilizing effectiveness of these new UV-absorbers for polypropylene (PP) has been determined. Results show that increasing the MW of the absorbers can decrease the loss of absorber from PP film during heat treatment but not in prolonged UV-irradiation. These four UV-absorbers are less efficient owing to their poor compatibility with PP. © 1996 Elsevier Science Limited.