| Late-transition metal Palladium(Ⅱ) catalyst [Pd[CH3C(O)CHC(Nnaphthyl)CH3]2, Pd(methyl-ketonaphthylimino)2, Pd(mektni)2] based onβ-ketoimine ligand [CH3C(O)CHC(NHnaphthyl)CH3,β-methyl-ketonaphthylimine] were synthesized and characterized. The polymerizations of NB were carried out in toluene solution by using Pd(mektni)2/B(C6F5)3 catalytic systems. The influence of polymerization conditions such as the polymerization time, the polymerization temperature, the monomer concentrations, the molar ratio of B/[Pd] were studied. The results indicated that the catalyst exhibited catalytic of 2.85×104 gPNB/molPd·h. However, the homopolymer is insoluble in organic solvents due to high stereo regularity of the structure, such as chloroform, THF, acetone, tolunene, chlorobenzene and o-dichorobenzene. When the polymerization temperature is 60℃, B/[Pd] molar ratio of 25, increasing the polymerization time can enhance the conversion of polymerization products. Monomer concentration has little effected on catalytic activity. TGA analysis results showed that the copolymer exhibited good thermal stability (Td>320℃). And WXRD analysis results showed that the copolymer exhibited noncrystalline.The Vinyl-type copolymerizations of norbornene (NB) and 5-norbornene-2-yl-acetate (NB-OCOCH3) were carried out in toluene solution by using Pd(mektni)2/B(C6F5)3 catalytic systems. The influence of comonomer feed ratio on the copolymerization activity and copolymer compositions in copolymerization were investigated. The achieved copolymers were confirmed to be vinyl-addition copolymers through the FTIR,1H NMR, and 13C NMR spectra analysis. The incorporation rate was 0.90-23.5 mol% ester units at a content of 10-90 mol% of the NB-OCOCH3 in feeds. And to produce functionalized norbornene copolymer bearing ester functionalities with narrow molecular weight distributions (Mw/Mn= 1.31-1.71) and moderate molecular weight (Mw= 1.9×104-2.7×104 g/mol). The copolymers are noncrystallinity by WAXD analysis results. TGA analysis results showed that the copolymer exhibited good thermal stability (Td>300℃).5-Norbornene-2-metheneoxy-trimethylsilyl (NB-CH2OSi(CH3)3) was synthesized by trimethylchlorosilane (ClSi(CH3)3) and 5-norbornene-2-methanol (NB-CH2OH) under the effect of triethylamine (N(C2H5)3). Copolymerization of NB-CH2OSi(CH3)3 and norbornene (NB) or Methyl 5-Norbornene-2-carboxylate (NB-COOCH3) was carried out in toluene by using novel Nickel(Ⅱ) complex [Ni(C10H8(O)C[N(naphthyl)CH3])2, Ni(benzocyclohexan-ketonaphthylimino)2, Ni(bchkni)2] in combination with cocatalyst B(C6F5)3. The influence of comonomer feed ratio on the copolymerization activity and copolymer compositions in copolymerization were investigated. Researching on Ni(bchkni)2/B(C6F5)3 catalyzing the copolymerzation of NB-CH2OSi(CH3)3 and NB in toluene solution shows that the catalyst exhibitied high catalytic activity (2.28×104-3.33×104 gpolymer/molNi·h). However, the solubility of polymers was too poor to characterize. Researching on Ni(bchkni)2/B(C6F5)3 catalyzing the copolymerzation of NB-CH2OSi(CH3)3 and NB-COOCH3 in toluene solution shows that the catalyst exhibitied high catalytic activity (0.547×104-3.03×104 gpoiymer/molNi·h). The achieved copolymers were confirmed to be vinyl-addition copolymers through the FTIR,1H NMR, and 13C NMR spectra analysis. The NB-CH2OSi(CH3)3 contents in the copolymers were 8.65-86.7% for Ni(bchkni)2/B(C6F5)3 by varying the comonomer feed ratios from 10 to 90%. And to produce functionalized norbornene copolymer with narrow molecular weight distributions (Mw/Mn= 1.60-2.24) and moderate molecular weight (Mw= 1.57×104-6.01×104g/mol) of copolymer with the copolymers containing 0-18.7% of NB-CH2OSi(CH3)3. The copolymers are noncrystallinity by WAXD analysis results. In addition, the copolymers in which the NB-CH2OSi(CH3)3 contents were 8.65-18.7 % show good solubility in common organic solvents, such as tetrahydrofuran, chloroform and toluene, while the copolymers containing 48.4-86.7% of NB-CH2OSi(CH3)3were insoluble in these solvents. |
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