| N-substituted maleimides are excellent functional monomers which can improve the thermal properties of polymers when they are copolymerized with common monomers because of the five-number imide rings in the molecule. The homopolymerizations of N-phenylmaleimide(NPMI), N-Octadecylmaleimide (NODMI) and the copolymerizations of NPMI with styrene(St), propylene oxide(PO), epichlorohydrin (ECH), methyl methacrylate(MMA) and cyclohexene (CHE) were investigated using rare earth coordination catalysts for the first time.Homopolymerization of NPMI was studied by binary rare earth coordination catalyst: La(P507)3-Al(i-Bu)3 system and the suitable polymerization conditions obtained were as follows: [La(P507)3]=10-2 molL-1, [Al(i-Bu)3]=8.0 x l0-2 mol L-1 , [NPMI] =5.0xl0-1 mol L-1, 60℃, 6h. NMR and FT-IR characterizations of the polymer indicated that polymerization of NPMI was proceeded via the opening the double carbon-carbon bond in the NPMI molecules. The polymer PNPMI possessed good thermal stability with initial thermal decomposition temperature at 390℃ and maximum thermal decomposition temperature 420℃ Coordination polymerization mechanism was proposed: the monomer molecule coordinates with the active center in the catalyst, opening the double bond to proceed the polymerization.Synthesis of NODMI was studied and the polymerization of NODMI by La(P507)3- Al(i-Bu)3 system was investigated for the first time. The optimum conditions for the polymerization were: [La(P507)3]=10-2 mol L-1, [Al(i-Bu)3]=8.0 x 10-2 mol L-1 , [NODMI] =5.0x10-1 molL-1, 60℃, 6h. Results showed that the polymer PNODMI had high molecular weight. The initial thermal decomposition temperature of the polymer was 360℃ and maximum thermal decomposition temperature 441℃.Copolymerization of NPMI with St by Nd(naph)3- AlEt3 system was studied. The preferred conditions were: Nd(naph)3=5.0xl0-3 mol/L, [NPMI]=[St] =4.5x 10-1 mol/L, Al/Nd=9, 50℃, 6h. Characterization of the copolymer P(NPMI-St) showed that P(NPMI-St) has an alternating structure. The obtained reactivity ratios of the monomers were r(NpMI)=0.06185, r(St)=0.01507. Coordinationcopolymerization mechanism with the participation of the charge transfer complex between NPMI and St was suggested. The P(NPM3-St) showed good thermal stability with no obvious decomposition under 350℃. The initial thermal decomposition temperature was 380℃ and maximum thermal decomposition temperature 430℃Terpolymerization of NPMI, St and MAn was also investigated by La(naph)3 -AlEt3 system. The suitable polymerization conditions were La(naph)3=5.0x10-3 mol/L, [NPMI]= [MAn]=2.25 x l0-1 mol/L, [St]= 4.5 x 10-1 mol/L, Al/Nd=6; 50℃, 2h, Characterization of P(NPMI-St-MAn) verified that the polymer obtained were the terpolymer of the three monomers. The P(NPMI-St-MAn) had good stability with weight loss only 2.7wt% at 300℃. The initial thermal decomposition temperature of P(NPMI-St-MAn) was 320 ℃ and the maximum thermal decomposition temperature 405℃.Copolymerization of NPMI with PO catalyzed by rare earth coordination catalyst La(P507)3-Al(i-Bu)3 system was investigated. The optimal conditions obtained were [La]-10-2 mol L-2, [Al(i-Bu)3]=8.0 X 10-2 mol-L-1, [PO]=[NPMI] =4.0X 10-1 mol L-1, 60℃, 6 h. The reactivity ratios of the two monomers in the La(P507)3-Al(i-Bu)3 system were r(NPMi)= 1.441 and r(po)=0.209. The UV-vis spectrum of the polymerization mixture at the initial stage showed that the active center had a stronger ability to coordinate with NPMI than that with PO, resulting in more NPMI units in the copolymer.Using Nd(P507)3-Al(i-Bu)3 binary catalyst system, copolymerization of NPMI with ECH was studied. The preferred conditions were: [Nd]=10-2mql L-1,. [Al(i-Bu)3]/[Nd(P507)3]=8, [M]/ [Nd(P507)3]=100, [NPMI]=[ECH], 60℃, 4h,, The copolymers were characterized by NMR, FT-IR and TGA. TGA results showed that P(NPMI-ECH) possessed excellent thermal stability with an initial thermal decomposition temperature at 311 ℃. Because of the ECH units in the copolymer, P(NPMI-ECH) had two...
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