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Structure and Morphology Control in Polymer Aerogels with Low Crosslink Density

Shinko, Andrew
http://orcid.org/0000-0001-5051-0795
http://rave.ohiolink.edu/etdc/view?acc_num=akron1430399529

Abstract Details

2015, Doctor of Philosophy, University of Akron, Polymer Engineering.
An array of mesoporous polymeric aerogels is synthesized in this work via gelation in condensation polymer systems. The monomers are chosen to yield softer, stiffer, or packable chains, and aerogel morphologies with controllable pore size distribution and surface area. A trifunctional amine crosslinker at low concentration (<1 wt%) is used in each case. The first system consists of polyurea aerogels with the porosity and shrinkage controlled via hydrogen bonding. These aerogels have mean pore diameters 9-16 nm, bulk density 0.19-0.26 g/cm3, porosity 79-86%, surface areas 106-309 m2/g, and compressive moduli of 12-69 MPa. The second system involves resilient poly(urethane urea) aerogels synthesized from aliphatic polyols. These aerogels are slightly more dense than polyurea aerogels (0.20-0.35 g/cm3) with similar porosity (71-85%), lower surface areas (47-163 m2/g), and similar compressive moduli (12-52 MPa). The polyol weight fraction can be used to control the extent of hydrogen bonding involving urea and urethane groups and consequently the aerogel shrinkage. In the third polymer system, polyimide and poly(urethane urea) segments are combined in the same poly(imide urethane urea) chains to yield aerogels with additional stiffness from the polyimide moieties. These aerogels are less dense (0.10-0.22 g/cm3) with higher porosity (82-92 %), and surface area between 117-358 m2/g. The surface area increases and the pore size distribution narrows as the polyol content is lowered. The fourth system focuses on translucent polyimide aerogels. These aerogels have low density (0.10-0.37 g/cm3), high porosity (73-93%), and high surface area (378-858 m2/g) due to rough fibrillar building blocks and narrow pore size distributions, and high compressive moduli (13-67 MPa). In the final system, a one-pot synthesis method is used to obtain fluorinated polyimide gels and aerogels. These polyimide aerogels are structurally uniformity at nano- and micro-scales, indicating that the fluorinated and non-fluorinated groups are blended homogenously. The materials produced in this work cover a wide range of mechanical stiffness, surface area, and bulk density. It is anticipated that these materials will meet the needs in a number of applications such as nanoparticle separation from air, separators for batteries, and thermally insulating mechanically robust housing for sensors.
Sadhan Jana, Dr. (Advisor)
Mary Ann Meador, Dr. (Advisor)
Kevin Cavicchi, Dr. (Committee Chair)
Bryan Vogt, Dr. (Committee Member)
Mesfin Tsige, Dr. (Committee Member)
Gang Cheng, Dr. (Committee Member)
238 p.
Engineering; Materials Science; Polymer Chemistry; Polymers
aerogels; polymers; polyurethane; polyurea; materials science; foams; polyimide; insulation; block copolymers

Recommended Citations

Citations

  • Shinko, A. (2015). Structure and Morphology Control in Polymer Aerogels with Low Crosslink Density [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1430399529

    APA Style (7th edition)

  • Shinko, Andrew. Structure and Morphology Control in Polymer Aerogels with Low Crosslink Density. 2015. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1430399529.

    MLA Style (8th edition)

  • Shinko, Andrew. "Structure and Morphology Control in Polymer Aerogels with Low Crosslink Density." Doctoral dissertation, University of Akron, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1430399529

    Chicago Manual of Style (17th edition)

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