Ring-Opening Metathesis Polymerization Of Norbornene Derivatives And Novel "3+2" Cycloaddition Condensation Polymerization

Phosphorus-containing polymer(PCP)has been widely used as flame-retardant material,sewage treatment agent,and critical component in tissue engineering,drug delivery,dental restoration,proton exchange membrane and so on.In this thesis,a series of PCPs were synthesized via ring-opening metathesis polymerization(ROMP)method,and their properties of flame retardancy and photo-lithographic performance were investigated.In another experiment,a novel condensation polymerization via "3+2" cycloaddition reaction of azide and olefin was discovered by chance.The important results and conclusions are as follows,(1)Phosphonated and epoxy-containing norbornene based monomers were prepared by Dieis-Alder reaction.They were then successfully combined with three other commercial cyclic unsaturated monomers to synthesize a series of phosphonated homo-and copolymers by ROMP using second generation Grubbs catalyst.Glass transitions of these polymers are in a broad range from-14 to 91 ℃ by varying the flexibility of comonomer.Interestingly,pbosphorus-containing copolymerization with cyclopentene inhibited the crystallization of polycyclopentene,and instead,leads to a copolymer with two marked Tgs.Paradoxically,results from thermogravimetric analysis were not completely consistent with the followed flame-retarding experiment,implying that the relatively early weight loss from phosphonated moieties didn’t deleteriously affect the flame-resistant property which actually depended more on the percentage of char residual after thermal degradation.In application studies,the morbomene derivative phosphonated polymer was tested for the first time as flame retarding material,and showed significant self-extinguishing ability.In a second study,photolithography was also successfully performed via thiol-ene "click" chemistry,which allowed the phosphanated polymer a promising negative photoresist.(2)Two types of norbornene derivative monomers with azido end groups were synthesized.They were found to be polymerizable by self-condensation through "3+2" cycloaddition to afford triazoline connections.Dimer,trimer,tetramer and etc.were identified in the mixture for the monomer with spacer of 11 CH2s by MS.Thin layer chromatography(TLC),Fourier transform infrared spectroscopy(FTIR),nuclear magnetic resonance spectroscopy(NMR),gel permeation chromatography(GPC),mass spectrum(MS),differential scanning calorimetry(DSC)and thermogravimetric analysis(TGA)were applied to characterize the products and track the spontaneous self-condensation during storage.It was found that the reaction can proceed even when kept in freezer(-22 ℃)without any catalyst.