Copolymerization of 5-norbornene-2- metheneoxy-trimethylsilyl with methyl 5-norbornene-2-carboxylate catalyzed by a novel Ni(benzocyclohexan-ketonaphthylimino)_2/ B(C_6F_5)_3) system

摘要

Copolymerization of 5-norbornene-2-methene-oxy-trimethylsilyl [NB-CH_2OSi(CH_3)_3] with norbornene (NB) or methyl 5-norbornene-2-carboxylate (NB-COOCH_3) was carried out in toluene by using novel nickel(II) complex catalyst systems, Ni(benzocyclohexan-ketonaphthylimino)_2/B(C_6F_5)_3 [Ni(bchkni)_2/B(C_6F_5)_3]. The catalyst system showed high activity on the copolymerization of NB-CH_2OSi(CH_3)_3 with NB (2.3-3.3 × 10~4 g_(poiymer)/mol_(Ni)) and NB-CH_2OSi(CH_3)_3 with NB-COOCH_3 (0.5-3.0×10~4 g_(poiymer)/mol_(Ni· h). However, the solubility of copolymers of NB-CH_2OSi(CH_3)_3 with NB and NB-CH_2OSi(CH_3)_3 with NB-COOCH_3, which contain 18.7-86.7 mol% of NB-CH_2OSi(CH_3)_3, was too poor to characterize. The achieved copolymers were confirmed to be vinyl-addition copolymers through the analysis of FTIR, H NMR, and ~(13)C NMR spectra. The incorporation rate was 8.7-86.7 mol% at a content of 10-90 mol% of the NB-CH_2OSi(CH_3)_3 in the monomer feeds ratios. The obtained ester functionalized NB copolymer containing 8.7-18.7 mol% of NB-CH_2OSi(CH_3)_3 showed a moderate molecular weight (M_w= 1.6-6.0×10~4 g/mol) and relative narrow molecular weight distribution (M_w/M_n = 1.6-2.2). Thermogravimetry (TGA) analyses results showed that the copolymers exhibited good thermal stability (T_d=330-350℃) and were noncrystalline by WAXD analyses results.