2026-09-23T04:51:53Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/114046 2023-07-11 col_2142_5131 col_2142_13836 com_2142_5130 com_2142_13835 com_2142_234

Sottos, Nancy R Sottos, Nancy R Moore, Jeffrey S Evans, Christopher M Schweizer, Kenneth S 2022-04-29T21:58:16Z 2024-04-29T21:58:46Z 2021-12 Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2023-12-01 The student, Douglas Ivanoff, accepted the attached license on 2021-10-05 at 09:13. The student, Douglas Ivanoff, submitted this Dissertation for approval on 2021-10-05 at 09:21. This Dissertation was approved for publication on 2021-10-11 at 13:07. DSpace SAF Submission Ingestion Package generated from Vireo submission #17148 on 2022-04-29 at 16:09:04 Made available in DSpace on 2022-04-29T21:58:16Z (GMT). No. of bitstreams: 2 IVANOFF-DISSERTATION-2021.pdf: 9498675 bytes, checksum: 623b1f174740307d419d6b2b89f174e6 (MD5) LICENSE.txt: 4212 bytes, checksum: 67d9db06b08947f29e5aa6e48ea5f417 (MD5) Previous issue date: 2021-10-11 Embargo set by: Seth Robbins for item 123411 Lift date: 2024-04-29T21:58:46Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system Author requested closed access (OA after 2yrs) in Vireo ETD system Limited application/pdf en text Improved properties, performance and recyclability of thermoset polymers and composites processed by frontal ring-opening metathesis polymerization (FROMP) Ivanoff, Douglas George 2021-10-11 Materials science 2022-04-29T21:58:16Z Frontal polymerization (FP) allows for a reduction in both energy and time required for production of polymeric materials by utilizing the large exothermic heat of polymerization to cure the material. The research described in this thesis explores and quantifies the effect of cure method on the thermomechanical behavior of composites and polymers while addressing the need for new FP monomers that allow for new functionalities, such as heat-resistance and recyclability. Frontal ring-opening metathesis polymerization (FROMP) of dicyclopentadiene (DCPD) has been demonstrated for the fabrication of neat polymers and fiber reinforced polymer composites (FRPC). Comparison of FRPCs with an epoxy matrix and pDCPD matrix reveals a weak interface between pDCPD and carbon fiber, reducing the mechanical properties. The limitation in interface strength is addressed in traditionally cured pDCPD by including adhesion promoters in the DCPD to react with the surface functionality of the carbon fibers. Structural components require high stiffness at elevated temperatures, necessitating high-glass transition temperature (Tg) polymers. The FROMP of DCPD resultants in thermosets with a Tg of ~130 °C, restricting use to low-temperature applications. The limitation on the maximum operating temperature of pDCPD is addressed by synthesizing norbornene-based crosslinking co-monomers. Frontally polymerizing crosslinking co-monomers with DCPD reduces the molecular weight between crosslinks (Mc), resulting in a polymer with a significantly higher Tg ( > 215 °C). Many thermosets have been designed without an end-of-life strategy and are inherently difficult to recycle into useful compounds. The incorporation of cyclic olefins featuring acetal or silyl ether linkages into DCPD allows for FROMP of pDCPD thermosets that fully deconstruct into oligomers with hydroxyl functionality. The material is upcycled by combining the deconstruction fragments with a diisocyanate to form a new polyurethane network with a Tg of 155 °C. The thermomechanical limitations imparted by the comonomers are overcome by synthesizing difunctional crosslinkers connected via a deconstructable silyl ether linkage. Development of new FROMP monomers enables control over reaction kinetics and thermodynamics, crosslinking density, and chemical stability of the resultant polymers. The research improves the library of FROMP monomers in two major categories: multifunctional crosslinking and degradable/recyclable. The first class is approached by synthesizing compounds featuring norbornene moieties, and recyclability is achieved via incorporation of dynamic silyl ether and acetal bonds in the polymer backbone and between crosslinks. Thesis eng http://hdl.handle.net/2142/114046 Copyright 2021 Douglas Ivanoff Materials Science & Engineerng Materials Science & Engr University of Illinois at Urbana-Champaign Dissertation Ph.D.