Synthesis and characterization of novel diblock copolymers of 5-(N-carbazoyl methyl)bicyclo[2.2.1]hept-2-ene and 5-(phthalimide methyl)bicyclo[2.2.1]hept-2-ene via living ring-opening metathesis polymerization

摘要

Ring-opening metathesis polymerization (ROMP) has been performed with {RuCl_2(CHPh)[P(C_6H_11)_3]_2} catalyst to make low polydispersity block copolymers of 5-(N-carbazoyl methyl)bicyclo[2.2.1]hept-2-ene (CbzNB) and 5-(phthalimide methyl)bicyclo[2.2.1]hept-2-ene (NBMPI). Three diblock copolymers with the CbzNB and NBMPI were made, varying both molecular weight and percent of each block. The hydrogenated diblock copolymers were successfully obtained by using p-toluenesulfonylhydrazide as a reducing agent. The novel diblock copolymers were characterized by means of gel permeation chromatography (GPC) ~1H NMR, fluorescence, differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). The molecular weight distributions of the diblock copolymers are narrow (M_w/M_n approx 1.5). Unhydrogenated diblock copolyers exhibited a strong carbazole fluorescence, with monomer emission occurring in the near-UV at approximately 380 nm and extending into the blue-violet region. Similar results were also observed on hydrogenated diblock copolymers. All diblock copolymers exhibited good solubility in a variety of solvents such as methylene chloride, chloroform, tetrahydrofuran and 1,2-dichlorobenzzene; however, there was no remarkable difference between unhydrogenated and hydrogenated diblock copolymers. Two T_g values were observed for the CbzNB segment and the NBMPI segment before and after hydrogenation. Unhydrogenated diblock copolymers exhibited good thermo-oxidative stability, losing 10% mass in the range 369-389 deg C in air and 400-416 deg C in nitrogen. However, hydrogenated diblock copolymers showed beteer thermal stability than unhydrogenated diblock copolymers, and 10% mass loss temperatures were recorded in the range 375-396 deg C in air and 415-428 deg C in nitrogen.