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Anionically Polymerized Supramolecular Thermoplastic Elastomers

Kumar, Nishant C
http://rave.ohiolink.edu/etdc/view?acc_num=akron1427128414

Abstract Details

2015, Doctor of Philosophy, University of Akron, Polymer Science.
Oligomers of Nylon 3 (Oligo(β-alanine)) were used as monodisperse hard blocks in poly(butadiene) and poly(isoprene) based thermoplastic elastomers. All polymers were of linear ABA tri-block architecture. The dicarboxy or dihydroxy terminated diene mid-blocks were synthesized via anionic polymerization and served as the B block while oligo(β-alanine) served as the A block. A series of low-vinyl content (Mn ~60K, 12% vinyl) poly(butadiene)s were functionalized with oligo(β-alanine)n (n = 2, 3, 4) and hydrogenated, forming low-butyl content poly(ethylene-butylene) (PEB) polymers. To reduce the crystallinity of the hydrogenated mid-block, two other diene mid-blocks were synthesized. The first was a set of high-vinyl content, dicarboxy terminated poly(butadiene)s (A. Mn ~44K, 30% vinyl B. Mn ~116K, 46% vinyl). High-butyl content PEB polymers resulted after hydrogenation. The second was a set of dicarboxy terminated poly(isoprene)s (Mn ~15K, 44K, 98K), forming poly(ethylene-propylene) (PEP) polymers after hydrogenation. Another dihydroxy terminated poly(isoprene) (Mn ~18K) was synthesized. Each polymer was oligo(β-alanine)4 functionalized. FT-IR spectroscopy showed β-sheet formation for all of the synthesized polymers. The low-butyl set behaved as a physically cross-linked network and acted as an elastomeric solid at 105 °C by rheological measurements at ≤1.2 wt% of β-alanine peptide. These materials were classified as `solids’. The high-butyl content PEBs formed physically cross-linked networks but did not act as stable, elastomeric solids at 105 °C. The dihydroxy terminated PEP acted in similar fashion to the high-butyl PEB after oligo(β-alanine) functionalization. These were classified as `solid-liquid’ materials. The remaining PEP samples did not form physically cross-linked networks and acted as higher molecular weight, chain-extended structures. They were classified as `liquid’ materials. The sterics of the mid-block end-group immediately adjacent to the oligo(β-alanine) end-group likely led to disruption in the β-sheet stacking, thus not allowing complete crystallization of the oligo(β-alanine) units to take place. The varying degree of disruption led to three types of materials, indicating that the mid-block end-group was a key factor in determining the formation of a physically cross-linked network. When β-sheet stacking was completely disrupted as in the `liquid’ classified polymer, the addition of a supramolecular filler resulted in the formation of a physically cross-linked network.
Li Jia, Dr. (Advisor)
Matthew Becker, Dr. (Committee Member)
Gary Hamed, Dr. (Committee Member)
Coleen Pugh, Dr. (Committee Member)
Kevin Cavicchi, Dr. (Committee Member)
177 p.
Chemistry; Polymer Chemistry; Polymers
Anionic Polymerization, Thermoplastic Elastomer, Nylon 3, Beta-alanine

Recommended Citations

Citations

  • Kumar, N. C. (2015). Anionically Polymerized Supramolecular Thermoplastic Elastomers [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1427128414

    APA Style (7th edition)

  • Kumar, Nishant. Anionically Polymerized Supramolecular Thermoplastic Elastomers . 2015. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1427128414.

    MLA Style (8th edition)

  • Kumar, Nishant. "Anionically Polymerized Supramolecular Thermoplastic Elastomers ." Doctoral dissertation, University of Akron, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1427128414

    Chicago Manual of Style (17th edition)

akron1427128414
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This open access ETD is published by University of Akron and OhioLINK.