Sulfur/Selenium/Telelium Ether Functionalized Lactone:Synthesis,Polymerization And Polymer Property

Polyester materials are widely used in many fields such as biomedicine,automobile manufacturing,electronics manufacturing,construction materials,and environmental protection.Ring-opening polymerization of cyclic lactones is one of the important ways to prepare polyester materials.Among these lactones,poly(y-butyrolactone)is currently the focus of research in the field of polymer materials and synthesis due to its property of completely degrading and recycling monomers However,y-butyrolactone was considered a non-polymerizable monomer in earlier years due to its low strain energy.In recent years,researchers have achieved efficient polymerization of ?-butyrolactone through the development of new high-efficiency catalysts,such as:lanthanide metal complexes,a novel cyclic phosphazene superbase CTPB and a thiourea/tBu-P4 dual-functional organic catalytic system.The conditions for these polymerizations are still relatively harsh and need to be carried out at low temperatures which is not conducive to large-scale production.However,it has been found through research that the introduction of a fused ring structure enables the polymerization to proceed efficiently at 30? and obtain a polyester material whose structure of main chain is the same as poly(?-butyrolactone).In this thesis,based on previous investigations,a monomer with a new structure of y-butyrolactone was synthesized by introducing functional groups.A new polyester was synthesized through ring-opening polymerization and the monomer structure was expanded to synthesize a series of functional monomers.The polymerization reactions involved in them have been studied.The details were summarized as the following(1)Preparation of high performance polyester containing sulfur/sulfone/sulfoxide and improvement of hydrophilicity of PET fiberA novel functionalized lactone monomer,4-(phenylthio)-6-oxabicyclo[3.2.1]octane-7-one(PhSGBL),was successfully prepared by reaction of a commercial diphenyl disulfide with an unsaturated carboxylic acid.A novel sulfide-containing polyester PPhSGBL was prepared by the ring opening polymerization of PhSGBL achieved at 30? using ethylene glycol as the initiator and the commercial reagent 1,5,7-triazabicyclo[4.4.0]dec-5-ene(TBD)as the catalyst.The kinetics studies of polymerization show that the process of polymerization is living polymerization and the monomer can be randomly copolymerized with caprolactone.The glass transition temperature of polyester is 94.2? which is significantly higher than that of common polyester materials.At the same time,the glass transition temperature of the copolymer obtained by random copolymerization with caprolactone could be adjusted in the range of-60?-94.2? by adjusting the ratio of the two monomers.The ester group structure in the main chain of PPhSGBL also imparts good degradation ability to the polyester.The thioether group could be controlled to be oxidized into sulfone or sulfoxide by m-chloroperoxybenzoic acid utilizing the controllable oxidative reactivity of the phenyl sulfide group on the side chain.A sulfone or sulfoxide-containing polyester was successfully prepared.The obtained polyester showed significantly higher hydrophilicity than the phenylsulfide polyester owing to the relatively polar structure of the sulfone and sulfoxide.At the same time,the glass transition temperature and thermal decomposition temperature of the polymer obtained by oxidation were improved to a certain degree.The moisture absorption rate of PET fiber was increased from 0.845%to 1.56%by blending the sulfone-containing polyester with better hydrophilicity with polyethylene terephthalate(PET).(2)Preparation of selenium-containing high performance polyesterWe synthesized 3,5-cis six-membered ring containing phenyl selenide group-fused ?-butyrolactone(GBL)by classical selenone lactonization[3,5-6CPhSeGBL(PhSeGBL)].A novel selenium-containing polyester was obtained by ring-opening polymerization using ethylene glycol as an initiator and catalyzed by a commercial catalyst 1,5,7-triazabicyclo[4.4.0]dec-5-ene(TBD)at 30?.The glass transition temperature of functional polyester PPhSeGBL is up to 112.1? and its initial decomposition temperature is 231.0?.The monomer can be copolymerized randomly with caprolactone and the glass transition temperature of the copolymer obtained by random copolymerization with caprolactone could be adjusted in the range of-60?-112.1? by adjusting the ratio of the two monomers.The initial decomposition temperature can also be adjusted in the range of 231.0?-314.5? by adjusting the ratio of the two monomers.At the same time,the polyester can be degraded by acid under heating conditions or can be selectively degraded into monomers under heating conditions using ZnCl2 as a catalyst and a single monomer recovery rate can reach up to 92.3%.It provides a strategy for the preparation of high-performance selenium-containing polyester.At the same time,the introduction of multi-reactive group selenium ether group is expected to achieve multifunctional integration of polyester materials(3)Synthesis of telluride-containing caprolactone and its regulation on free radical polymerization of styrene?-Phenyl telluride caprolactone(PhTeCL)was synthesized by the introduction of phenyl telluride into ?-position of caprolactone through organic reaction.Azobisisobutyronitrile(AIBN)was used as the initiator and PhTeCL was used as the regulator.The reaction temperature was 70? and the reaction time was 12 hours.The free radical polymerization of styrene was carried out.The molecular weight of Polystyrene obtained by the polymerization above was up to 15400 g/mol and the molecular weight distribution was only 1.27 indicated that PhTeCL has a good regulation effect on the free radical polymerization of styrene.Under the same conditions,the polystyrene prepared by this method was used as a macromolecular initiator to regulate the radical polymerization of styrene.The molecular weight of the polymer increased from 15400 g/mol to 25200 g/mol and the molecular weight distribution changed from 1.27 to 1.22.The polymerization activity was confirmed.On the other hand,it is expected to realize new-type ring-opening and radical hybridization polymerization to prepare new polymer materials owing to the ROP of lactones.