Synthesis and Thermal Characterization of Precision Poly(ethylene-<i>co</i>-vinyl Amine) Copolymers

Abstract

A structural investigation of linear ethylene-co-vinyl amine (EVAm) copolymers having a primary amine branch on every 9th, 15th, 19th, or 21st carbon along the ethylene backbone has been completed using step polymerization chemistry. Acyclic diene metathesis (ADMET) polymerization has been used with symmetrical α,ω dienes containing protected amine groups to afford polymers with exact primary structures and constant methylene run lengths between branches. The effects of subtle structural changes such as the ethylene run lengths between amine branches can be observed and used to correlate structure property relationships. NMR and FT-IR techniques are used to characterize and verify the excellent structural control this synthetic approach provides over traditional chain polymerization techniques. Thermal decomposition of these copolymers is shown to additionally support polymer structure while differential scanning calorimetry demonstrates crystallinity in the polymers with an amine on every 15th and 21st carbon, whereas the polymer with an amine on every ninth carbon is amorphous. Variations of the physical and spectral properties are discussed as a consequence of the amine branch spacing, protection, and saturation of the ethylene backbone.