Study on polymerization conditions in homo- and copolymer syntheses of norbornene/1-hexene with nickel-based late-transition metal catalyst

Norbornene (NB) homopolymerization as well as its copolymerization with 1-hexene (H) were investigated using nickel-based catalyst. The effects of Al/Ni ratio, temperature and time of polymerization on reaction activities were studied. The highest activity for norbornene polymerization was obtained at 25 ℃, 24 h and Al/Ni = 1000. M v of the homopolymers decreased with increasing the polymerization temperature from 0 to 50 ℃ and increasing the Al/Ni ratio from 500 to 1500; while it increased upon increasing the polymerization time from 3 to 24 h and was nearly linear with time. The glass transition temperature of the homopolymer obtained at the highest activity was 242 ℃. DSC results showed that the NB/H copolymers have amorphous structures and showed a T g above 200 ℃. It was found that increasing of 1-hexene content from 14 to 20.2 leads to a decreased T g of the resultant copolymers by 12–18 ℃. The highest incorporation of comonomer (1-hexene) was found to be 24.5%. In addition, it was found that for the NB/H: 85/15 feed ratio in copolymer, increasing the reaction temperature from 40 to 50 ℃ increased the 1-hexene content of the copolymers from 14.1 to 22.7% and decreased the activity from 4.3 to 2.1 (g/mol Ni) × 10 5 , respectively. Graphical abstract