Styrene And Its Derivatives Polymerization Catalyzed By Rare-earth Metal Catalysts

In this thesis,a series of styrene derivatives were synthesized and their homo-and co-polymerization with styrene were studied.A variety of well-defined?co?polymers were obtained by using a ternary catalytic system composed by rare-earth-metalcomplexes?Flu-CH₂-Py?Y?CH₂SiMe₃?₂?THF??1?,?Flu-CH₂-Py?Lu?CH₂SiMe₃?₂?THF??2?,?Flu-CH₂-Py?Sc?CH₂SiMe₃?₂?3?or?Flu-SiMe₃?Sc?CH₂SiMe₃?₂?THF??4?,[Ph₃C][B?C₆F₅?₄]andAlⁱBu₃.The microstructures and properties of the?co?polymers were also studied.The results are listed as following.?1?Atroomtemperature,catalyticsystemsconstitutedby constrained-geometry-configuration rare-earth-metal complexes 1,2 or 3 with[Ph₃C][B?C₆F₅?₄]/AlⁱBu₃ were used to homopolymerize 2-vinylnaphthalene?2VN?or2-vinyl-6-methoxynaphthalene?MVN?with perfect syndioselectivity?rrrr>99%?.The polymerization activity could reached up to 3.15×10⁶g mol_Sc^-1h^-1 while the molecular weight distributions were narrow?PDI=1.35-1.45?.Syndiotactic poly?MVN?couldbetransformedintosyndiotactic poly?2-vinyl-6-hydroxynaphthalene?by treatment with boron tribromide at-20?.The atactic poly?1-vinylnaphthalene?[P?1VN?]was synthesized by using4/[Ph₃C][B?C₆F₅?₄]/AlⁱBu₃.?2?A series of para-alkyl(CH₃-C₂₃H₄₇)substituted styrenes were synthesized,and the syndioselective polymerizations of these monomers were realized by using a catalytic system consisting of?Flu-CH₂-Py?Y?CH₂SiMe₃?₂?THF??1?/[Ph₃C][B?C₆F₅?₄]/AlⁱBu₃.For linear alkyl-substituted styrenes,the polymerization activity increased with the increasing of the number of carbon atoms.The homopolymerization activity for 4-tricosylstyrene could reach up to 3.80×10⁶ g mol_Y^-1h^-1,and the molecular weight distributions remained narrow?PDI=1.16-1.57?.According to DSC analysis of the obtained polymers and comparison of DSC patterns of the number of carbon atoms of different substituents,it was found that the glass transition temperature of the polymer increased as the number of substituent carbon atoms increased.These polymers showed distinct crystallization behaviours,which was related to the number of carbon atoms?n?on the substituent directly.When the number of carbon atoms on the substituent is less than 7,the polymer has no melting peak;when the number of carbon atoms is 9,11,the polymers have a cold crystallization peaks;and the number of carbon atoms is over 13,the melting point tends to increase as the number of carbon atoms increases.?3?The copolymerization of 4-nonadecylstyrene and styrene was realized by using the catalytic system 1/[Ph₃C][B?C₆F₅?₄]/AlⁱBu₃.The polymers displayed different thermodynamic properties by adjusting the different contents of the4-nonadecylstyrene in the copolymers.These copolymers were characterized by DSC,TGA,AFM,etc.According to the DSC results,a melting point at about 250? could be observed when the content of comonomer was 1%or 2%.However,it appeared another melting point at about 60? when the comonomer content was 8%and 10%.The glass transition temperature of copolymers were lower than that of syndiotactic polystyrene?100??and decreased with the increasing of the comonomer content.All the copolymers have a good thermal stability and the initial decomposition temperature was above 390? by TGA.There has been a slight phase separation in all copolymers by atomic force microscopy?AFM?.