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Anionic Synthesis of In-chain and Chain-end Functionalized Polymers

Roy Chowdhury, Sumana
http://rave.ohiolink.edu/etdc/view?acc_num=akron1156257315

Abstract Details

2006, Doctor of Philosophy, University of Akron, Polymer Science.
The objective of this work was to anionically synthesize well-defined polymers having functional groups either at the chain-end or along the polymer chain. General functionalization methods (GFM) were used for synthesizing both kinds of polymers. Chain-end functionalized polymers were synthesized by terminating the anionically synthesized, living polymer chains using chlorodimethylsilane. Hydrosilation reactions were then done between the silyl-hydride groups at the chain-ends and the double bonds of commercially available substituted alkenes. This produced a range of well-defined polymers having the desired functional groups at the chain-ends. In-chain functionalized polymers were synthesized by anionically polymerizing a silyl-hydride functionalized styrene monomer: (4-vinylphenyl)dimethysilane. Polymerizations were done at room temperature in hydrocarbon solvents to produce well-defined polymers. Functional groups were then introduced into the polymer chains by use of hydrosilation reactions done post-polymerization. The functionalized polymers produced were characterized using SEC, 1H and 13C NMR, FTIR, MALDI TOF mass spectrometry and DSC. The monomer reactivity ratios in the copolymerization of styrene with (4- vinylphenyl)dimethylsilane were also measured. A series of copolymerizaions was done with different molar ratios of styrene(S) and (4-vinylphenyl)dimethylsilane (Si). Three different methods were used to determine the values of the monomer reactivity ratios : Fineman-Ross, Kelen-Tudos and Error-In-Variable (EVM) methods. The average values of the two monomer reactivity ratios obtained were: rSi = 0.16 and rS = 1.74. From these values it was observed that in the copolymerization of styrene with(4-vinylphenyl)dimethylsilane, the second monomer was preferentially incorporated into the copolymer chain. Also, rSirS = 0.27, which shows that the copolymer has a tendency to have an alternating structure. Amino acid-functionalized polymers (biohybrids) were synthesized by using a simple and efficient, three-step method. The first step was to make a copolymer of Styrene with (4-vinylphenyl)dimethylsilane, followed by introduction of amine functional groups into the polymer chain, using a hydrosilation reaction between the silyl-hydride units in the copolymer chain and the double bond of allyl amine. The third step was a condensation reaction between these amine functional groups on the copolymer chain and the carboxyl group on N-carbobenzyloxy-phenylalanine(a protected amino acid). Although this method has been used to incorporate a particular amino acid onto the polymer chain, it maybe possible to extend this procedure to introduce virtually any amino acid or peptide group into the polymer chain. Finally a thermoplastic elastomer (TPE) was synthesized using the monomer (4- vinylphenyl)dimethylsilane. The first block of this TPE was a copolymer block of styrene with (4-vinylphenyl)dimethylsilane, followed by a polyisoprene block and finally another copolymer block of styrene and (4-vinylphenyl)dimethylsilane. This polymer was characterized using SEC, 1H and 13C NMR, FTIR, DSC, DMTA, TEM and tensile testing. It was seen to exhibit properties similar to those of a regular styrene-diene-styrene TPE. However, the silyl-hydride units introduced into this polymer chain can be easily converted to different functional groups using hydrosilation reactions. Introduction of such functional groups would be helpful in tailoring the properties of the TPE.
Roderic Quirk (Advisor)
193 p.
Anionic; hydrosilation; polymer

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Citations

  • Roy Chowdhury, S. (2006). Anionic Synthesis of In-chain and Chain-end Functionalized Polymers [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1156257315

    APA Style (7th edition)

  • Roy Chowdhury, Sumana. Anionic Synthesis of In-chain and Chain-end Functionalized Polymers. 2006. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1156257315.

    MLA Style (8th edition)

  • Roy Chowdhury, Sumana. "Anionic Synthesis of In-chain and Chain-end Functionalized Polymers." Doctoral dissertation, University of Akron, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=akron1156257315

    Chicago Manual of Style (17th edition)

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This open access ETD is published by University of Akron and OhioLINK.