Polynorbornene with cross-linkable side chains via ring-opening metathesis polymerization

The ring-opening metathesis polymerization (ROMP) of 5-(methyl methacryloyl isocyanate)bicyclo[2.2.1]hept-2-ene [i.e., norbornene containing methacryloyl isocyanate (NBMMAI)] having cyclic olefin and terminal double bond was investigated in order to produce novel polymers with cross-linkable side chains under ligand exchange with MMA by using {RuCl2(CHPh)[P(C6H11)(3)](2)} (II) as catalyst. Results of infrared spectra, H-1 NMR, and C-13 NMR showed that poly(NBMMAI) contains polynorbornene backbone ring structure and methacryloyl side chains. The H-1 NMR spectrum of poly(NBMMAI) showed new vinyl protons as a broad signal between 5.15 and 5.37 ppm in the ratio of 0.4 and 2.8, corresponding to the vinyl protons of the cis and trans double bond of the ring-opened polymer, respectively. Gel formation was still observed in the polymerization of NBMMAI using ruthenium catalyst II with 20 mol % p-methoxyphenol (MEHQ). An increase in bulkiness of the ligand reduced the cross metathesis reaction and led to reduced activity for the catalyst. Increasing the ratio of monomer concentration [M] to catalyst [cat] resulted in the formation of higher molecular weight polymers and polymer yield. The incorporation of poly(NBMMAI) into poly(methyl methacylate) (polyMMA) to produce AB cross-linked materials was accomplished. These cross-linked materials had higher thermal stability and solvent resistance than pure polyMMA.