Synthesis Of Functionalized Polyethers By Ring-Opening Coordination Copolymerization Of Epoxides

Polyether materials with polar and flexible-C-O-C-backbone have excellent properties,such as low temperature flexion,flexibility,heat resistance,ozone resistance and hydrophilicity.These unique physical and chemical properties leading polyether materials be widely used in the fields of life sciences,energy sciences,and materials science.The incorporation of pendant functionalized groups into polyether may afford functionalized materials having excellent property of polyether which makes up the lack of functionality of polyether and develops functionalized polyether with properties such as pharmacological,photoelectric,catalytic,surface,and stimulus response activity,which is an inevitable trend for polyether to meet the market demands and the development of new technologies.In this thesis,alkylaluminon-phosphonate catalysts i-Bu3Al/H3PO4/lewis base for industrial application were synthesized,and the scientific problem of the low polymerization activity and serious chain transfer reaction in the polymerization of functionalized epoxides were solved.The high-efficient and controlled polymerization of functionalized epoxides and their copolymerization with epoxides afforded a series of polyether with precise controllable composition,function and polymer structure.(1)The lewis base in i-Bu3Al/H3PO4/lewis base catalysts affected the ring-opening polymerization activity of epoxides and the structure of their copolymers significantly.By using all of the i-Bu3Al/H3PO4/lewis base catalyst,the polymerization of epichlorohydrin(ECH)afforded atactic ECH polymer with high molecular weight and narrow distribution,but the polymerization activity was different.The polymerization activity order was 1,8-diazabicycloundec-7-ene(DBU)>N,N-diethylaniline(DEBA)>2-dimethylaminopyridine(o-DMAP)>4-dimethylaminopyridine(p-DMAP)>1,3,5-triazine(TRZ)>N-methylimidazole(MMI).The activity of ECH-ethylene oxide(EO)copolymerization was consistent with ECH homopolymerization by using different i-Bu3Al/H3PO4/lewis base catalyst.Adjusting the lewis base in i-Bu3Al/H3PO4/lewis base catalyst,the EO-ECH copolymers with random,gradient and trapper sequence structures were efficiently obtained.Using the optimized high-performance catalyst i-Bu3Al/H3PO4/DBU,the polymerization of EO and ECH showed controllable/living polymerization characteristic which afforded the corresponding(co)polymers with high molecular weight.The polymerization of propylene oxide(PO)and cyclohexene oxide(CHO)occurred chain transfer reaction and afforded the corresponding polymers with molecular weight of 20,000?30,000 g/mol.(2)Using the optimized i-BU3Al/H3PO4/DBU catalyst,the efficient homopolymerization of halogen,alkynyl,furan,C=C,acrylate,carbazolyl and azophenyl functionalized epoxides and their copolymerization with EO were achieved,to afford a series of high molecular weight,narrowly distributed functionalized polyether materials,and the random distribution of functionalized epoxides in the copolymers was realized By sequential and simultaneous copolymerization of glycidyl 3-butynyl ether(GBE)with EO and ECH,the alkynyl-functionalized diblock and triblock polyethers with controllable molecular weight,block sequence and block ratio and the alkynyl-functionalized random polyethers with controllable molecular weight and composites were synthesized correspondingly.Based on the living/controlled polymerization of GBE,ECH and EO,the star-shaped alkynyl functionalized polyethers with controllable number of arms and molecular weight were synthesized by the"living chain crosslinking method" using a multi-epoxy monomer as a coupling agent.(3)Using the optimized i-Bu3Al/H3PO4/DBU catalyst,the copolymerization of fluorinated epoxides 2,3,4,5,6-pentaflourinephenyl glycidyl ether(PFPGE),3,4,5-triflourinephenyl glycidyl ether(TFPGE),4-monoflourinephenyl glycidyl ether(MFPGE)with ECH were efficiently achieved to afforded fluoride polyepichlorohydrin elastomers with random and block distribution of fluorinated epoxides.The introduction of TFPGE improved the mechanical properties of polyepichlorohydrin elastomers significantly.Using the optimized i-Bu3Al/H3PO4/DBU catalyst,the random copolymerization of furfuryl glycidyl ether(FGE)with ECH and EO have been achieved to afforded a new family of furan functionalized polyepichlorohydrin elastomers with controllable composition.Based on the Diels-Alder reaction of furan functionalized polyepichlorohydrin elastomers with 4,4'-methylenebis(N-phenylmaleimide),a new series of thermoreversible cross-linked polyepichlorohydrin elastomers was successfully synthesized.These thermoreversible cross-linked polyepichlorohydrin elastomers possessed tunable mechanical properties by adjusting the content of FGE units.The mechanical properties of thermoreversible cross-linked polyepichlorohydrin elastomers were significantly better than those of the traditional vulcanized polyepichlorohydrin elastomers,which could be used as structural material without reinforcing agents.More importantly,the DA cross-linked polyepichlorohydrin elastomers could be remolded and self-healed without loss of performance.