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New Applications for Linear and Arborescent Polyisobuylene-Based Thermoplastic Elastomers

Charif Rodriguez, Andrea Carolina
http://rave.ohiolink.edu/etdc/view?acc_num=akron1425420506

Abstract Details

2015, Doctor of Philosophy, University of Akron, Polymer Science.
Linear poly(styrene-b-isobutylene-b-styrene) (l-SIBS) and arborescent poly(styrene-b-isobutylene-b-styrene) (arb-SIBS) are a type of polyisobutylene-based thermoplastic elastomers (PIB-based TPE) characterized by an excellent mechanical, thermal and chemical stability, low permeability and excellent biostability and biocompatibility. PIB-based TPE are prepared by living carbocationic polymerization with sequential monomer addition which allows to obtain narrow molecular weight distribution and to synthesize a wide variety of architectures. These materials have been extensively used for biomedical applications, however they have a unique combination of properties, not available in any other TPE, that make them suitable for potential uses in other areas as well. This work reports the evaluation of three new potential technological applications for l-SIBS and arb-SIBS. In the first part of this work a new method for the preparation of a flexible piezoelectric polymer by incorporating a bent-core liquid crystal (BLC) in a PIB-based TPE, l-SIBS was shown. The polymer composite material containing 10 wt. % of BLC showed a piezoelectric charge constant d33 (~1 nm V-1) greater than commercially available piezoelectric ceramics. Small angle X-ray scattering (SAXS) results show that the liquid crystal–polymer composite becomes aligned during compression molding leading to macroscopic polarization without electric poling. In the second part of this work l-SIBS and arb-SIBS were sulfonated to prepare block copolymer ionomers. The materials were successfully sulfonated to various sulfonation degrees (SD), and characterized for water uptake and ionic conductivity. This modification significantly increased water uptake of both S-l-SIBS and S-arb-SIBS; the associated proton conductivity of the S-l-SIBS increased with the SD, however it did not rise at the desirable levels. For the S-arb-SIBS low values of proton conductivity were obtained, possibly due to the limited solubility of the sulfonated materials that led to the poor quality of the membranes. Finally, in the last part of this work, the use of PIB-based TPE arb-SIBS and a new PIB-based TPE poly(alloocimene-b-isobutylene-b-alloocimene) (AIBA) for drug delivery systems was explored. Aspirin containing electrospun fiber mats of arb-SIBS and of AIBA were successfully prepared. The morphology, hydrophobicity and drug eluting properties of the fiber mats were characterized. The aspirin was successfully incorporated into the PIB-based fiber mats through the electrospinning process. The highly hydrophobic fiber mats showed a control release of aspirin after an initial burst release of 24 h. These findings demonstrated the capabilities of fiber mats of arb-SIBS and AIBA as drug eluting systems. It was demonstrated the versatility of the PIB-based TPEs l-SIBS and arb-SIBS by providing three novel potential applications. By taking advantage of their properties, these elastomers were used to create innovative materials with additional characteristics such as piezoelectricity, conductivity and drug eluting ability. Further research efforts on the exploration of the resourcefulness of PIB-based TPEs will surely promote the generation of original applications in a wide range of fields.
Judit E. Puskas, Dr (Advisor)
Gary R. Hamed, Dr. (Committee Member)
Mesfin Tsige, Dr. (Committee Member)
Darrell H. Reneker, Dr. (Committee Member)
Thein Kyu, Dr. (Committee Member)
282 p.
Materials Science; Polymer Chemistry; Polymers
PIB-based thermoplastic elastomers, liquid crystals, composites, liquid crystal elastomers, drug release fiber mats, sulfonated PIB-based TPE

Recommended Citations

Citations

  • Charif Rodriguez, A. C. (2015). New Applications for Linear and Arborescent Polyisobuylene-Based Thermoplastic Elastomers [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1425420506

    APA Style (7th edition)

  • Charif Rodriguez, Andrea. New Applications for Linear and Arborescent Polyisobuylene-Based Thermoplastic Elastomers. 2015. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1425420506.

    MLA Style (8th edition)

  • Charif Rodriguez, Andrea. "New Applications for Linear and Arborescent Polyisobuylene-Based Thermoplastic Elastomers." Doctoral dissertation, University of Akron, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1425420506

    Chicago Manual of Style (17th edition)

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