Effect of zinc salts on the spontaneous copolymerization of 4-vinylpyridine with various electron-rich vinyl monomers

✍ Scribed by Takaki Kanbara; Michael G. Mikhael; Anne Buyle Padias; H. K. Hall Jr.

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 122 KB
• Volume: 35
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(19970930)35:13<2787::aid-pola24>3.0.co;2-6

✦ Synopsis

The spontaneous copolymerization of 4-vinylpyridine (4-VP) complexed with three different zinc salts (chloride, acetate, and triflate) with various electronrich vinyl monomers (p-methoxystyrene, MeOSt; p-methylstyrene, MeSt; a-methylstyrene, a-MeSt; p-tert-butylstyrene, BuSt; styrene, St) was investigated in methanol at 75ЊC. Increasing the zinc salt concentration or the nucleophilicity of the electron-rich monomer increased the copolymer yields. All obtained copolymers are characterized by high molecular weight (10 5 ) and broad molecular weight distribution. Both 1 H-NMR and elemental analyses confirmed the almost 1 : 1 copolymer structure. Changing the anion of the zinc salt does not have a considerable effect either on the copolymerization rate or on the molecular weight. The proposed mechanism exhibits the formation of a s-bond between the b-carbons of the two donor-acceptor monomers. This creates the 1,4-tetramethylene biradical intermediate which can initiate the copolymerization reaction.