An Investigation Into the Synthesis of Poly(Co-Maleic Anhydride/Iso-Butyl Vinyl Ether) with RAFT Polymerisation

An Investigation Into the Synthesis of Poly(Co-Maleic Anhydride/Iso-Butyl Vinyl Ether) with RAFT Polymerisation

The University of New South Wales Faculty of Engineering School of Chemical Sciences and Engineering Centre for Advanced Macromolecular Design (CAMD) An investigation into the Synthesis of Poly(co-maleic anhydride/iso-butyl vinyl ether) with RAFT polymerisation A Thesis in Industrial Chemistry by S. C. Lea Submitted for the degree of Masters of Science in Industrial Chemistry October 2006 Table of contents List of symbols.............................................................................................. i Chapter 1. Introduction .............................................................................. 1 References................................................................................................. 3 Chapter 2. Chemistry and mechanism of radical polymerisation............. 4 2.1 Free radical polymerisation ………………………………………...4 2.1.1 Initiation .................................................................................... 4 2.1.2 Propagation............................................................................... 6 2.1.3 Termination ............................................................................... 7 2.1.4 Chain transfer........................................................................... 8 2.1.4.1 Transfer agents....................................................................... 9 2.1.4.2 The transfer constant Ctr and the re-initiation constant Cri... 9 2.1.5 Number and weight average molecular weight ...................... 10 2.1.6 Kinetics of FRP ....................................................................... 11 2.1.7 Kinetic chain length and degree of polymerisation ................ 14 2.1.8 Effect of the transfer agent on the degree of polymerisation.. 15 2.1.9 Molecular weight distribution................................................. 16 2.2 Living radical polymerisation (LRP)……………………………...18 2.3 Features of living radical polymerisation(LRP)…………………..18 2.3.1 LRP processes: Nitrogen Mediated Polymerisation (NMP)... 20 2.3.2 LRP processes: Atom Transfer Radical Polymerisation (ATRP) ………………………………………………………………………..21 2.3.3 LRP processes: Reversible Addition-Fragmentation chain Transfer (RAFT) .................................................................................. 21 2.3.3.1 Mechanism of the RAFT polymerisation.............................. 22 2.3.3.2 Choice of the RAFT agent.................................................... 25 2.3.3.3 Side reactions in RAFT polymerisation ............................... 27 2.3.3.4 Copolymerisation using the RAFT system ........................... 28 2.3.3.4.1 Random copolymers....................................................... 28 2.3.3.4.2Diblock and triblock copolymers.................................... 29 References...............................................................................................30 Chapter 3. Copolymerisation systems in radical polymerisation............ 32 3.1 Definitions………………………………………………………...32 3.2 Copolymer composition…………………………………………..33 3.2.1 The Terminal model ................................................................ 34 3.2.2 Explicit and Implicit Penultimate Models............................... 37 3.2.3 The Q-e approach to the theory of reactivity.......................... 39 3.3 Influence of the reaction medium…………………………………41 3.4 Alternating copolymers…………………………………………...42 3.4.1 Copolymers of vinyl ethers and maleic anhydride.................. 43 3.4.1.1 Maleic anhydride (MAn)...................................................... 44 3.4.1.2 Vinyl ethers........................................................................... 45 3.4.1.3 Co (maleic anhydride-alt-methyl vinyl ether)...................... 46 3.4.1.4 The synthesis of co (maleic anhydride-alt-iso-butyl vinyl ether)……………………………………………………………….47 References……………………………………………………………...48 Chapter 4. The free radical polymerisation of iso-butyl vinyl ether and maleic anhydride....................................................................................... 50 4.1 Experimental procedure................................................................. 50 4.1.1 Purification of reagents and solvents...................................... 50 4.2 Polymerisation procedures ............................................................ 51 4.2.1 Polymerisation in Schlenck tubes............................................ 51 4.2.2 Polymerisation in the presence of DDM as a chain transfer agent…………………………………………………………………………..51 4.2.3 In situ NIR-FTIR spectroscopy polymerisation....................... 52 4.3 Polymerisation kinetics ................................................................. 52 4.3.1 In situ FT- NIR spectroscopy .................................................. 52 4.3.2 1H NMR spectroscopy ............................................................. 54 4.3.3 Gravimetric analysis ............................................................... 55 4.4 Copolymer characterisation........................................................... 56 4.4.1 13C NMR spectroscopy ............................................................ 56 4.4.2 Size Exclusion Chromatography ............................................. 56 4.5 Results and discussion................................................................... 58 4.5.1 FRP in dioxane as a solvent.................................................... 58 4.5.2 FRP in MEK and Acetone as solvents..................................... 61 4.6 Reliability of FT-NIR spectroscopy for the evaluation of the conversion............................................................................................... 66 4.7 Reliability of NMR spectroscopy for the determination of the conversion............................................................................................... 70 4.8 Experiments with dodecylmercaptan (DDM) as a chain transfer agents ...................................................................................................... 72 4.9 Conclusions ................................................................................... 75 References............................................................................................... 75 Chapter 5. Use of RAFT agents to control the radical copolymerisation of MAn and IBVE..................................................................................... 76 5.1 Experimental procedure................................................................. 76 5.1.1. Purification of reagents and solvents...................................... 76 5.2 RAFT agents synthesis.................................................................. 76 5.2.1. Synthesis of benzyl dithiobenzoate (BDTB) ............................ 76 5.2.2. Synthesis of 3-benzyl sulfanyl thiocarbonyl sulfanyl-propionic acid (RAFT acid) ................................................................................. 76 5.2.3. Synthesis of dibenzyl trithiocarbonate (DBTTC) .................... 77 5.3 Polymerisation procedures ............................................................ 77 5.3.1. Polymerisation in Schlenck tubes............................................ 77 5.3.2. In situ NIR-FTIR spectroscopy polymerisation....................... 78 5.4 Polymerisation kinetics ................................................................. 78 5.4.1. In situ FT-NIR spectroscopy .................................................. 78 5.4.2. 1H NMR spectroscopy ............................................................. 78 5.4.3. Gravimetric analysis ............................................................... 78 5.5 Copolymer characterisation........................................................... 79 5.5.1. 13C NMR spectroscopy ............................................................ 79 5.5.2. Size Exclusion Chromatography…………………………………79 5.6 Use of RAFT agents for the control of the molecular weight....... 79 5.6.1. 3-benzyl sulfanyl thiocarbonyl sulfanyl-propionic acid (RAFT acid) and dibenzyl-trithiocarbonate (DBTTC) as RAFT agents. ........ 83 5.7 BDTB as a RAFT agent ................................................................ 89 5.7.1. RAFT polymerisation with BDTB in polar solvents................ 89 5.7.1.1 Acetone................................................................................. 89 5.7.1.2 Ethyl acetate and N, N, dimethyl acetamide........................ 97 5.7.1.3 Characterisation of the two phases....................................... 98 5.7.2. RAFT polymerisation with BDTB in 1,4 dioxane as a solvent ………………………………………………………………………105 5.7.3. Tetrahydrofuran as a solvent ................................................ 117 5.8 Investigation into the colour alteration of a polymerisation mixture containing BDTB as a RAFT agent...................................................... 125 5.9 Conclusions ................................................................................. 127 References............................................................................................. 129 List of symbols and abbreviations Ac = acetone AM = acrylamide CM = chain transfer constant for chain transfer to the monomer CS = chain transfer constant for chain transfer to the solvent or chain transfer agent DMAc = N, N dimethyl acetamide DEE – diethyl ether DPn = number average degree of polymerisation DPw = weight average degree of polymerisation d = number of chains generated by radical-radical termination Eth Ac = ethyl acetate f =initiator efficiency I = generic initiator molecule I = generic

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