Synthesis of polymers with pendant diamondoid groups

Abstract Two oligomers and three polymers with diamondoid side groups were prepared by the insertion polymerization of N-octenyladamantane and -diamantane, as well as by polymer-analogous reactions. The molecules consist exclusively of carbon and hydrogen atoms and one secondary amino group per repeating unit. Depending on the charge state (neutral or protonated), the glass transition temperature of the oligomers can be tailored between -30 and approximately 70 °C. We assume that the presence of bulky substituents and amino groups is responsible for the low degree of polymerization (DP) achieved in insertion polymerization. This limitation was circumvented by using commercially available poly(vinylbenzyl chloride) and subsequent polymer-analogous reactions with corresponding aminodiamondoids. The resulting polymers exhibited a nearly quantitative degree of functionalization (DoF), which was determined by NMR (Nuclear Magnetic Resonance) spectroscopy and largely confirmed by elemental analysis and thermogravimetry. All the materials exhibit high thermal stability up to 200 °C or 250 °C. The higher homolog diamantane displays a higher DP and higher yields in functionalization reactions than the corresponding adamantane derivatives do.