Synthesis And Characterization Of Homopolymers And Copolymers Of N-vinylpyrrolidone And Its Derivatives

Amphiphilic polymer is a special kind of polymer,which has double affinity to the external environment.The biggest characteristic is that it could occur microphase separation in selective solvents to form diversified structures.Monomer is the foundation of polymer,the structure,feeding ratio and order of monomers are the decisive factors affecting the microstructure of polymer.In this paper,a series of random or block copolymers were prepared by free radical polymerization based N-vinylpyrrolidone monomer(NVP)and lauryl methacylate(LMA)as the research objects.The effects of the structures of copolymers on the properties were discussed in detail.The details are listed as bellow.Two novel functionalized NVP monomers were synthesized by simple and efficient one-pot method(TBSE-NVP and[TBSE]₂-NVP,TBSE-NVP represents the uni-functional monomer and[TBSE]₂-NVP represents the difunctional monomer).Free radical homopolymerization based NVP monomers and LMA using AIBN as initiator was investigated at 70 ^oC.The results showed that the free radical polymerization exhibited good controllability and high conversion for monomers.Meanwhile,the introduction of the hydrophobic chain segment of butyl dimethylsiloxy decreases the activity of the monomer and enhances the hydrophobicity of the polymers.The free radical copolymerizations of NVP/[TBSE]₂-NVP,NVP/LMA,TBSE-NVP/LMA were researched by one-pot method.The results revealed that the copolymerization could occur in the NVP/[TBSE]₂-NVP system,which the two monomers has similar structures.In the NVP/LMA system,when the monomer feed ratio was increased to a certain extent,free radical copolymerization could occur and random copolymers could be formed,which the two monomers has different structure and property.While free radical copolymerization occurred between TBSE-NVP and LMA,which are both hydrophobic groups,indicating that the structure and property of monomers are the decisive factors for the occurrence of free radical copolymerization.It also showed that the hydrophilicity/hydrophobicity,thermal stability,T_m and the morphology of the self-assembly for the polymers were determined by the polymer components.The free radical copolymerizations of NVP/LMA and TBSE-NVP/LMA systems were prepared by sequential feeding method.In the NVP/LMA or TBSE-NVP/LMA system,when the monomer feed ratio was relatively low,the copolymerization did not occur.While increasing the feed ratio to a certain extent,the copolymerization could occur and copolymers could be formed.For the sequential feeding method,the feed ratio and structure of the monomers are the key factors for the free radical copolymerization.However,the obtained copolymers are block or random copolymers,it still needs to be certified by NMR and the kinetics of polymerization reaction.In this paper,the homopolymerization and copolymerization of N-vinylpyrrolidone derivatives and LMA were researched by one-pot or sequential feeding method.The structures and the properties were studied in detail and the results indicated the structure,property and feeding ratio of the monomers are the key factors for the free radical polymerizations.This result provides certain theoretical basis and reference for the functional copolymers and laids a solid theoretical foundation for the synthesis and application of copolymers.