Synthesis And Property Of Antimicrobial Poly(amino Acid)s And Poly(ester Amide)s

Amino acids are a kind of renewable resources with various structures and low price.With the increasing progress of biotechnology,the industrial production of amino acids has developed rapidly.Such as,the production of lysine are overcapacity.However,the synthesis of poly(amino acid)s materials with high added-value are deficient.Therefore,it is a project need to studied eagerly that develop the polymerization method from cyclic amino acids in polymer science.In previous work,we synthesized the antimicrobial poly(ε-lysine)via ring opening polymerization of cyclic lysine,which gain breakthrough development.Based on the previous research work,the aim of this work is to develop efficient catalytic system and copolymerization of cyclic lysine and caprolactam to achieve synthesis of antimicrobial poly(ε-lysine)and copolymer of lysine and caprolactam.In addition,the functional poly(ester amide)s were develop via organocatalytic ring-opening polymerization of methionine derived cyclic monomer.The main results obtained in this dissertation are summarized as follows:1 We screened six commercial catalysts,including organic and inorganic bases.we performed a detailed investigation of the ring-opening polymerization of cyclic lysine by the six bases.Among these bases,NaH and t-BuP2 are the most effective.The mechanism of ring-opening polymerization of cyclic lysine shows that the deprontonation of cyclic lysine in base is the key to generate anionic active species,which confirm the strength of base is crucial for the effective polymerization.In addition,poly(ε-lysine)with maximum number-average of 10.0 kDa was obtained in lage-scale.2 Antimicromial copolymer of lysine-caprolactam was synthesized via organocatalytic ring-opening copolymerization of dimethyl-protected cyclic lysine(DMCL)and caprolactam(CL)and followed by quaternization reaction.Antimicromial copolymer of lysine-caprolactam not only exhibit enough physical and mechanical properties but also demonstrate potent antimicrobial activities.The antimicromial copolymer of lysine-caprolactam with 25 mol%quaternary ammonium groups incorporation demonstrated complete killings for both S.aureus(Gram-positive)and E.coli(Gram-negative).3 We designed and synthesized a series of methionine-derived morpholine-2,5-dione monomers.We performed a detailed investigation of the organocatalyzed ring-opening polymerization of methionine-derived morpholine-2,5-dione monomers,and controlled ring-opening polymerization was delivered successfully.Functional poly(ester amide)s was obtained by "methionine click".The structures of methionine-derived morpholine-2,5-dione monomers and poly(ester amide)s were characterized by 1H NMR,13C NMR and MALDI-TOF MS.We studied the thermal properties of the poly(ester amide)s with different substituents by DCS,and the results show that the glass transition temperature can be adjusted by changing substituents.Poly(ester amide)s could be processed into a transparent film by the hot-pressing approach.