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Applications of Styrenic Thermoplastic Elastomers in Stimuli Responsive Dynamically Porous Materials and Ice Anti-Slip Composites

Namdari, Navid
http://orcid.org/0000-0003-4016-8900
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1639861934488202

Abstract Details

2021, Doctor of Philosophy, University of Toledo, Engineering.
Thermoplastic elastomers (TPEs) are a class of materials known for their low Young’s modulus and high yield strain. Their applications range from adhesives and seals to automotive parts, footwear, and medical components. This dissertation aims to develop new applications for styrenic TPEs in areas of stimuli sensing and winter safety. First, TPEs with controlled volumetric shape change sensitive to heat and chemical vapors are developed through the concept of dynamic porosity. Dynamically porous films are developed mainly from poly(styrene-ethylene/butylene-styrene) (SEBS) using an eco-friendly CO2 manufacturing method. It is shown that omnidirectional pore size changes above a glass transition temperature (Tg) for polystyrene (PS) physical crosslinks (i.e. 125 °C), which imparts the films with a controlled pore density and a porous-to-solid transition (PST). The tunable PST at a specific temperature is also concomitant with an opaque-to-transparent transition (OTT) useful for indication/detection of temperature. The PST and OTT concepts were further exploited for developments of actuators and vapor responsive films. The second part of this dissertation describes the development of an unconventional and facile strategy for crafting dynamically porous TPEs with an ability to undergo a PST in response to applied mechanical contact pressure at ambient conditions. The PST is shown to be reversible for multiple cycles by applying an in-plane stretch on the activated non-porous films. The PST transition leads to a three orders of magnitude reduction of pore density, resulting in a strong OTT contrast, which can act as a visual indicator for pore reversion and re-generation. Finally, it is shown that the pore reversion can be exploited to locally control the films’ mechanical and heat transfer characteristics. Given thousands of injuries involved with ice, sleet, or snow during winter, the development of surfaces with enhanced grip on such slippery surfaces would be deemed a significant societal benefit. The last part of this dissertation discusses damage induced surface texturing (DIST) which is a process that involves with the transversal cutting of TPE-based composites reinforced with fibers. The shearing process leads to debonding and pullout of fibers, resulting in surface texturing, which is beneficial for increasing grip on icy surfaces through fibers’ penetration into ice. Furthermore, ice friction measurements reveal a transition from a sliding regime to a stick-slip one, when 36 wt % of carbon nanofibers are used, thereby exhibiting a ×24 increase in the coefficient of friction (COF) compared to pristine samples. Two-dimensional materials are also employed to manufacture durable ice-traction materials. Lastly, a new large-area and low-cost approach is proposed to fabricate anti-slip surfaces. The novel approaches presented in this dissertation expand the rich diversity of TPEs’ applications.
Reza Rizvi (Advisor)
Engineering; Materials Science; Mechanical Engineering; Polymers
Thermoplastic elastomers; responsive polymers; optical functional polymers; pressure-responsive polymer, stretch-responsive polymers; slip-resistance; winter safety; surface texturing; ice traction; nanocomposite surfaces

Recommended Citations

Citations

  • Namdari, N. (2021). Applications of Styrenic Thermoplastic Elastomers in Stimuli Responsive Dynamically Porous Materials and Ice Anti-Slip Composites [Doctoral dissertation, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1639861934488202

    APA Style (7th edition)

  • Namdari, Navid. Applications of Styrenic Thermoplastic Elastomers in Stimuli Responsive Dynamically Porous Materials and Ice Anti-Slip Composites . 2021. University of Toledo, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1639861934488202.

    MLA Style (8th edition)

  • Namdari, Navid. "Applications of Styrenic Thermoplastic Elastomers in Stimuli Responsive Dynamically Porous Materials and Ice Anti-Slip Composites ." Doctoral dissertation, University of Toledo, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1639861934488202

    Chicago Manual of Style (17th edition)

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This open access ETD is published by University of Toledo and OhioLINK.
Release 3.2.12