Polymerizable ultraviolet stabilizers

A number of polymerizable ultraviolet stabilizers have been synthesized and their homo- and copolymerization studied. The initial work consisted of the synthesis of vinyl derivatives of methyl salicylate (three isomers), 2, -dihydroxy-benzophenone, and ethyl a-cyano-p-phenylcinnamate. More recently, vinyl derivatives (two isomers) and one isopro-penyl derivative of 2(2-hydroxyphenyl)2H-benzotriazole have been prepared. A number of benzotriazoles with more than one benzotriazole ring in the molecule, or compounds with both benzo(or aceto)phenone and 2(2-hydroxyphenyl)2H-benzo-triazole groups in one molecule, have also been synthesized. Acryloyl and methacryloyl derivatives of benzotriazole-substituted polyphenols have been prepared and homo- and copolymerized. 

Other polymerizable ultraviolet stabilizers and antioxidants have also been synthesized and incorporated into polymeric structures. 

Allyl groups have also been introduced in the 3 position of 2,k-dihydroxybenzophenone. Nucleophilic displacement reaction of the chloride in It—chloromethylstyrene by phenolates of 2,1+-dihydroxy-benzophenone (9) or 2(2-hydroxy-5-methylphenyl)l4- -hydroxybenzotria-zole also provided a method of producing styrene-type polymerizable ultraviolet stabilizers (9,10). 

Polymerizable Ultraviolet Stabilizers — Miscellaneous Types. In our research on polymerizable ultraviolet stabilizers, we have decided to prepare styrene-type monomers in which the vinyl (or isopropenyl) group is directly attached to the phenyl group of the stabilizer, which might be polymerized similarly to styrene. These monomers can indeed be polymerized and copolymerized successfully with styrene, acrylic and methacrylic acid derivatives with azobisisobutyronitrile (AIBN) as the radical initiator (12-Ut-). 

Styrene and methyl methacrylate copolymers onto UV stabilizer moieties that were fixed were characterized by UV spectroscopy and size exclusion chromatography. The stability of intramolecular hydrogen bonds is important for the performance of UV stabiUzers. The highest stability of the intramolecular hydrogen bonds is obtained for polymers with phen-ylbenzotriazole unit attached to the backbone. It was shown that the UV stabilizer units were statistically distributed along the polymer backbone. " A number of polymerizable ultraviolet stabilizers of the 2-(2-hy-drox5 henyl)-2H-benzotriazole t) es have been synthesized. E.g., 5-vinyl and 5-isopropenyl derivatives of 2-(2-hydroxyphenyl)-2H-benzotriazole and 4-acrylates or 4-methacrylates of 2-(2,4-dihydroxyphenyl)-2H-benzo-triazole or 2-(2,4-dihydrox5 henyl)-1,3-2H-dibenzotriazole have been prepared and copolymerized with various monomers. ... 

A number of polymerizable ultraviolet stabilizers of the 2-(2-hydroxyphenyl)-2H-benzotriazole types have been synthesized. E.g., 5-vinyl and 5-isopropenyl derivatives of 2-(2-hydroxyphenyl)-2H-benzotriazole and 4-acrylates or 4-methacrylates of 2-(2,4-dihydroxyph-enyl)-2H-benzotriazole or 2-(2,4-dihydroxyphenyl)-1, 3-2H-dibenzotriazole have been prepared and copolymerized with various monomers [53]. 

The incorporation of four different classes of important ultraviolet stabilizers into high polymer chains has been accomplished by synthesis of polymerizable, vinyl-substituted stabilizer derivatives followed by radical polymerization. 

Vogl, O. Albertsson, A.C. Janovic, Z. Polymerizable, polymeric, polymer-bound (ultraviolet) stabilizers. In Polymer Stabilisation and Degradation Klemchuk, P., Ed. ACS... 

Polymerizable, Polymeric, and Polymer-Bound (Ultraviolet) Stabilizers... 

Polymerizable 2(2-Hydroxyphenyl)2H-Benzotriazole Ultraviolet Stabilizers. Synthesis. Some of the most important ultraviolet stabilizers belong to the class of 2(2-hydroxyphenyl)2H-benzotriazoles. Ever since the early work on benzotriazoles by Elbs (25,24), a number of 2(2-hydroxyphenyl)2H-benzotriazoles [2H-benzotriazole-2-yl)2-hydroxy-benzene] have been prepared (25). Even some polymerizable compounds of this class had been synthesized. The benzotriazole stabilizing groups had in the past been attached to a polymerizable group via a phenolic hydroxyl group placed in the benzotriazole ring (26). 

For the last two decades, we have been studying the concept of polymerizable, polymeric or polymer-bound stabilizers. Vie have focused our efforts on non-leachable ultraviolet (UV) stabilizers with a major emphasis on 2(2-hydroxyphenyl)2H-benzotriazole derivatives and have reported extensively on this subject [1]. 

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