The syntheses of triorganotin polymers as a binder in antifouling paints

Abstract

Two triorganotin monomers, tri-n-butyltin methacrylate (TBTM) and tri-n-butyltin acrylate (TBTA) were synthesized by esterification of methacrylic acid (MA) or acrylic acid (AA) with bis (tributyltin) oxide (TBTO). Each monomer was copolymetized with methyl methacrylate (MMA) or tertiary butyl acrylate (t-BA) in toluene solution at 75±1℃ having benzoyl peroxide (BPO) as initiator. The proportion of monomer feeds were varied to give polymer products of over 85% yield. The structures of monomers and polymers were characterized by IR, ¹H NMR, ¹³C NMR and ¹¹⁹[superscript m]Sn Moessbauer spectroscopic technics. The mole fraction of monomer compositions in each copolymer was obtained from tin anslysis in the copolymers using AAS technic. From the copolymerization curves of monomer feeds versus monomers in the copolymers, TBTM-MMA showed azeotropic polymer at almost all compositions. The azeotropic compositions for TBTM-t-BA and TBTA-t-BA were in a wide range from 0.20-0.58 and 0.20-0.36 mole respectively, whereas TBTA-MMA gave no azeotropic composition. The reasons were under investigation. However, the study should be continued. Tin contents in the copolymers had great influence on some physical properties and film forming properties of the copolymers. Tg values of the polymers decreased whereas drying time and adhesion increased with increasing organotin contents in the copolymers.