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FIBER-COMPOSITE IN SITU FABRICATION: MULTILAYER COEXTRUSION AS AN ENABLING TECHNOLOGY

Jordan, Alex Michael
http://rave.ohiolink.edu/etdc/view?acc_num=case1467832877

Abstract Details

2016, Doctor of Philosophy, Case Western Reserve University, Macromolecular Science and Engineering.
Polymeric biomaterials, in the form of fibrous constructs and hydrogels, have received substantial attention in recent years, showing great promise in the field of regenerative medicine. The first half of this dissertation will discuss recent advances in multilayer coextrusion technology to fabricate matrix/fiber polyester composites of poly(ethylene oxide) (PEO) and poly(e-caprolactone) (PCL) and subsequent isolation of highly aligned rectangular fibers with micro- to nano-scale dimensions achieved through post-process uniaxial drawing with two kinetic regimes. Uniaxial drawing resulted in a 2.5-fold increase in specific surface area, a 30-fold increase in elastic modulus, and 10-fold tensile strength. Rectangular coextruded PCL fibers exhibited a 6-fold increase in specific surface area over corresponding circular, electrospun PCL fibers while maintaining similar thermo-mechanical properties. A two-stage distillation process was employed to recover ~100% pure water (95% recovery) and methanol (87% recovery) utilized during PEO removal. The distillation process enabled ~94% recovery of ~100% pure PEO coextruded as sacrificial matrix material that may be reintroduced to the coextrusion process, substantially decreasing process waste. The second segment of this talk focuses on a straightforward in situ post-process PEO crosslinking scheme to fabricate well dispersed, sub-micron scale fiber-reinforced hydrogels. By systematically varying feed rate, hydrogel compressive stiffness was tailored ranging between ~0.5 - 2 kPa, on par with values obtained from articular cartilage. Uniaxial drawing before hydrogel fabrication resulted in a 225% increase in hydrogel stiffness, while use of rigid poly(L-lactic acid) (PLLA) fibers increased gel stiffness 350%. Hydrogels fabricated using the in situ fabrication technique displayed increased stiffness and similar fibroblast cell viability when evaluated against hydrogels developed using electrospun PCL fibers and traditional additive gel impregnation. Finally, the influence of fiber type on hydrogel mechanics utilizing the in situ fabrication method provided a robust method to achieve targeted oligopotent cell differentiation. Advances in multilayer coextrusion technology have provided a flexible platform for in situ fiber-reinforced hydrogel development with a wide range of material and architectural control for tailored mechanical properties and achieving targeted stem cell differentiation in robust 3D hydrogel biomaterial constructs.
LaShanda Korley (Advisor)
Eric Baer (Committee Member)
Gary Wnek (Committee Member)
Mark Griswold (Committee Member)
257 p.
Chemical Engineering; Polymer Chemistry; Polymers
Multilayer Coextrusion; Matrix-Fiber Composites; Hydrogels; Tissue Engineering; Cell Scaffold; Polyesters

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Citations

  • Jordan, A. M. (2016). FIBER-COMPOSITE IN SITU FABRICATION: MULTILAYER COEXTRUSION AS AN ENABLING TECHNOLOGY [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1467832877

    APA Style (7th edition)

  • Jordan, Alex. FIBER-COMPOSITE IN SITU FABRICATION: MULTILAYER COEXTRUSION AS AN ENABLING TECHNOLOGY. 2016. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1467832877.

    MLA Style (8th edition)

  • Jordan, Alex. "FIBER-COMPOSITE IN SITU FABRICATION: MULTILAYER COEXTRUSION AS AN ENABLING TECHNOLOGY." Doctoral dissertation, Case Western Reserve University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1467832877

    Chicago Manual of Style (17th edition)

case1467832877
595
© 2016, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.