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Shape Memory Elastomers and Fatty Acid Organogelators: Functional Materials from Small Molecule Additives

Abstract Details

2013, Master of Science, University of Akron, Polymer Engineering.

The use of small molecules as additives is capable of imparting many desirable properties into materials which otherwise would not be possible for single component systems. The addition of crystallizing molecules into materials such as thermoplastic elastomers and fatty acids has shown the ability to create functional materials such as shape memory composites and organogels which have much industrial promise.

Crystalline phases comprised of small molecules were used to create styrene-ethylene/butylene-styrene (SEBS)-based shape memory elastomers and to probe the solution phase behavior of hydroxystearic acid (HSA) and stearic acid (SA). A 1:1 weight ratio of SEBS (Kraton G1650) and microcrystalline wax (IGI 5714) was used to create a tunable, triple shape memory elastomer. The shape memory composite (XSMP) exhibited a range of trigger temperatures from about 50-70°C with a fixity ratio of roughly 90%, though recovery ratios suffered due to the presence of creep. These figures of merit, however, were found to change based on the measurement method, either using dynamic mechanical analysis, or manual deformation in a water bath.

HSA and SA were mixed with co-crystallizing solvents of naphthalene, biphenyl and eicosane to create phase diagrams which were constructed from differential scanning calorimetric scans. X-ray analysis was also employed to elucidate the structural behavior of these organogelators once they have solidified from the melt. From X-ray analysis, it was concluded that the HSA and SA form triclinic crystal structures when mixed with naphthalene and biphenyl. Fitting with the Flory-Huggin’s equation shows that the melting point depressions of the crystalline solvents were best fit assuming the aggregation of the HSA and SA in the liquid state. This demonstrates the importance of entropic contributions to the solution phase behavior of these systems and should have implications for their ability to act as organogelators.

Kevin Cavicchi, Dr. (Advisor)
David Simmons, Dr. (Committee Member)
Robert Weiss, Dr. (Committee Member)
70 p.

Recommended Citations

Citations

  • Shin, J. (2013). Shape Memory Elastomers and Fatty Acid Organogelators: Functional Materials from Small Molecule Additives [Master's thesis, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1383340291

    APA Style (7th edition)

  • Shin, James. Shape Memory Elastomers and Fatty Acid Organogelators: Functional Materials from Small Molecule Additives. 2013. University of Akron, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1383340291.

    MLA Style (8th edition)

  • Shin, James. "Shape Memory Elastomers and Fatty Acid Organogelators: Functional Materials from Small Molecule Additives." Master's thesis, University of Akron, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1383340291

    Chicago Manual of Style (17th edition)