| Polynorbornene (PNB) exhibits excellent thermal stability, chemical stability, optical properties, and its poor processability, solubility and adhesion would be improved by copolymerizing with polar norbornene derivatives. The modified polynorbornene materials also have been endowed with some certain properties by the functional groups. A novel, effectual, stable catalyst in the modification process could improve the yield of the polymerization and properties of the polymer, so designing and synthesis of the catalysts with new structure would be a key researching subject.Two homogeneous catalysts and a supported catalyst were synthesized in this paper. Bis(benzocyclohexan-ketonabenzylimino) Pd(II) complex was synthesized firstly, and the structure was characterized by single crystal X-ray diffractions, NMR and elemental analysis. Compared to the catalysts in our previous work, the new complex contains benzocyclohexane and benzene, and the their steric effect and electronic effect could improve the activity of Pd(Ⅱ) complex. In the homopolymerization of norbornene, the Pd(Ⅱ)/B(C6F5)3exhibited high activity (2.1×105gpolymer/molpd·h), but the activity in the copolymerization of norbornene (NB) and5-norbornene-2-yl acetate (NB-OCOCH3) decreased a lot (0.4-2.0×104gpolymer/molpd·h). The obtained copolymer showed low molecular weight (4.53-5.06×103g/mol). The reactivity ratios of the two monomers were determined to be0.07of NB-OCOCH3,6.49of NB by the Kelen-TUdOs method. The obtained polymers were proved to be vinyl-addition type polymers by FT-IR and1H-NMR, and the insertion ratio of NB-OCOCH3increased with the increasing of its in-feed ratio. The polymers were characterized to be amorphous by WXRD, and the molecular packing density decreased with the increasing of NB-OCOCH3insertion ratio. The obtained polymers were proved to be pure copolymer by GPC and solubility tests. The copolymers exhibited high decompose temperature (317.5-400.0℃) and glass transition temperature (243-275℃), and decreased with the increasing of NB-OCOCH3insertion ratio. The Pd(II)/B(C6F5)3catalytic system showed poor tolerance to polar groups, so a Ni(II) complex bearing the same ligand was synthesized, the structure was also characterized by single crystal X-ray diffractions, NMR and elemental analysis. The Ni(II)/B(C6F5)3catalytic system exhibited high activity both in homopolymerization of NB (2.7×105gpolymer/molNi·h) and copolymerizatin of NB with NB-OCOCH3(0.7-2.3×105gpolymer/molNi·h). The polymer were vinyl-addition type, amorphous, pure copolymers, and showed high molecular weight (1.80-2.79×10g/mol), decompose temperature (319.9-421.1℃) and glass transition temperature (263.9-302.4℃). The reactivity ratios of the two monomers were determined to be0.08of NB-OCOCH3,7.94of NB by the Kelen-TUdOs method. The copolymer films were prepared by phase-transition method, and showed good transparence and mechanical properties. When the insertion ratio of NB-OCOCH3increased, molecular weight, molecular packing density, decompose temperature, glass transition temperature, transparence decreased and mechanical properties improved. Compared with Pd(Ⅱ)/B(C6F5)3catalytic system, Ni(II)/B(C6F5)3catalytic system showed higher activity, tolerance to polar groups and better insertion ratio of NB-OCOCH3, molecular weight, thermal properties and optical properties.A acetylacetone ligand-based Pd catalyst [(CH3CO)2CHPdCl2] was covalently attracted onto the surface of glass slides, and then surface polymerization of norbornene (NB) on glass slides were initiated by these Pd-terminated glass slides. Vinyl-type addition polynorbornene (PNB) layer obtained on the surface of glass slides were proved by ATR and SEM. When the polymerization time increased, the contract angles of the PNB-terminated glass slides surface increased as well as the thickness of the PNB layers. The thicknesses of the PNB layers were approximately controlled in0-44.0μm by varying the polymerization time from0.5h to24h. The researching on etching also has been operated. |
PDF Full Text Request