New route to functional polyolefins: sulfonation of poly[ethylene‐co‐(5,7‐dimethylocta‐1,6‐diene)] and evaluation of properties

An ethylene/5,7‐dimethylocta‐1,6‐diene copolymer was sulfonated using two different approaches, solution and surface modification, varying parameters such as reaction time, temperature and concentration of the sulfonation reagent. Techniques such as attenuated total reflectance Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy and elemental analysis confirmed the successful sulfonation of the copolymer by both methods. Water uptake studies showed that the polarity of the initial copolymer was markedly changed upon functionalization and that the sulfonation by the in‐solution method produced more hydrophilic polymers compared to the surface procedure. Moreover, differential scanning calorimetry and thermogravimetric analysis pointed out additional changes to the thermal properties of the sulfonated polymers relative to the copolymer precursor. This study showed that the sulfonation process of the non‐polar ethylene–diene copolymer led to a new hydrophilic material with a potential wide range of applications. © 2017 Society of Chemical Industry An ethylene/5,7‐dimethylocta‐1,6‐diene copolymer was successfully sulfonated using two simple approaches, solution and surface modification, leading to new hydrophilic materials, with increased water uptake.