Synthesis of Novel Cyclic Olefin Polymer with High Glass Transition Temperature via Ring-Opening Metathesis Polymerization

Three norbornene derivatives containing bulky hydrocarbon groups (M1-M3) have been prepared and polymerized efficiently via ring-opening metathesis polymerization (ROMP) using different Grubbs catalysts (G1-G3) to afford polymers in high yield. Gel permeation chromatography curves show that all the obtained polymers exhibit unimodal distribution. Unsaturated moieties in the main chain of the obtained polymers are hydrogenated based on the chemistry of the reactive intermediate diimide (HN. NH) in quantitative conversion, confirmed by 1H NMR measurement. All the polymers display relatively high thermal stability according to thermogravimetric analyses test. The results of differential scanning calorimetry measurement show that the cardo-like structure such as M2 and M3 is contributed to improve the Tg of cyclicolefin polymer materials. The highest Tg (up to 277 degrees C) of hydrogenated polymer H-PM3 is achieved, which is so far the highest value obtained by the ROMP approach, to the best of our knowledge. Furthermore, all the hydrogenated polymers show excellent transparency because of their amorphous structure.