Of Raft Synthesis Of Polymers And The Preparation Of The Ps / Ag Nanocomposites

Controlled synthesis of the copolymer is mainly controlling the structure and the molecules weight of the copolymer.At present,living radical copolymerization is one of the mostly actively study fields in macromolecules science.Living copolymerization is the ideal way to synthesis the copolymer with low polydispersity, and to control the copolymer molecules weight.What's more,block copolymers with predetermined structure and series could be easily synthesized via living copolymerization,so considerable attentions have been paid to the study on the living copolymerization.Reversible addition-fragmentation chain transfer(RAFT) is the ideal method to carry out the living copolymerization,which can realize most of the monomers to be freely/controlled radical copolymerization.In the RAFT reaction,usually by adding a reversible addition-fragmentation chain transfer agent(RAFT reagent) so that polymerization can be effectively controlled,the thio ester is a very efficient chain transfer reagent,the preparation of suitable chain transfer agent is successful Polymerization of the key.Polymer nanostructure compound materials are one emerging,multi-disciplinary industry with the broad research prospect.The silver/polymer compound materials simultaneously combine fine characteristic of nanometer silver with the polymer,and entrusts with the material some special or the new function,applying it at the photonics,electronics,the biomedicine and the information material and so on.Based on above idea,this paper has mainly completed following several aspect work:(1)Introducing the dithiobenzoate as the precursor,we successfully synthesized the cumyl dithiobenzoate and 2-(2-cyanopropyl) dithiobenzoate;Moreover,we prepare the Grignard reagent at first,then reacting with the CS₂ toobtain the S-benzyl dithiobenzoate;Preparation of trithiocarbonate compound is relatively simpler while the production rate is high,whose method is as follows,we synthesize it reacted with CS₂ under phase transfer catalysit's help and in the KOH solution as well as alkylogen system.And we has carried on the characterization with ¹H NMR to the product.The result indicated that the purity of product is high and it has provided the c hain transfer reagent for the next polymerization.(2)Using reversible addition-fragmentation chain transfer polymerization(RAFT) method, taking the dithiobenzoate as the chain transfer reagent,we have prepared polystyrene(PS), poly(methyl methacrylate)(PMMA),polystyrene-b-poly(4-vinylpyridine)-b-polystyrene (PS-b-P4VP-b-PS),poly(styrene-b-N-isopropylacrylamide)(PS-b-PNIPAM) and so on,whose polymer structure are confirmed with the FTIR and ¹H NMR.(3)Taking polystyrene(PS) as the stabilizer,we have prepared cube nanometer silver nanopaticles of good dispersivity under the ultrasonic.And we have carried on the characterization to nanocomposites.The result of FTIR indicated the chain structure of polystyrene was not destroyed under the ultrasonic.When introduced the polymer,silver nanopaticles dispersived better in the solution.The more AgNO₃ solution was added,the more silver nanopaticles are,making the surface of them absorbed completely by PS and possessing the regular morphologies.When AgNO₃ solution was added less,the quantity of Ag nanoparticles reduced at the same time,leaving PS not absorbing absolutely them and forming also the irregular PS/Ag colloid.