Date of Award

Summer 7-1-2022

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

School

Polymer Science and Engineering

Committee Chair

Jeffrey Wiggins

Committee Chair School

Polymer Science and Engineering

Committee Member 2

xiaodan gu

Committee Member 2 School

Polymer Science and Engineering

Committee Member 3

sergei nazarenko

Committee Member 3 School

Polymer Science and Engineering

Committee Member 4

Yoan Simon

Committee Member 4 School

Polymer Science and Engineering

Committee Member 5

Derek Patton

Committee Member 5 School

Polymer Science and Engineering

Abstract

We study monomer melt properties and polymer properties using two approaches. The first approach takes advantage of molecular dynamics to calculate monomer melt properties. The second approach involved an experimental investigation of polycyanurate networks with varying monomer functionality and rigidity.

For our computational study we applied an existing voids method by Solca et al. to calculate melting temperature for four different cyanate esters: (a) 2’-(4-cyanatophenyl) propane (BADCy), (b) 4,4'-(ethane-1,1-diyl) bis(cyanatobenzene) (LECy), (c) tris(4-cyantophenyl) methylsilane (SiCy-3), and (d) bis(4-cyanatophenyl) dimethylsilane (SiMCy). For systems with 1 to 10% voids, the predicted melting temperature decreased due to a decrease in the free energy barrier to melting.

We synthesized cyanate ester monomers from a plant source, resveratrol, and compared the properties to cyanate esters of bisphenol A and bisphenol E. Polymer properties were characterized via DSC, DMA, and TGA. The increase in functionality and backbone rigidity of the resveratrol polycyanurates produced networks with glass transition temperatures up to 296 °C and char yields up to 70 %. Additionally, thermal, thermo-oxidative, and ablative properties were measured by TGA, TGA-MS, cone calorimetry, SEM, and EDX. Cone calorimetry data revealed that networks from cisResCy produced a decrease in Total Heat Release.

Monofunctional and trifunctional cyanate ester monomers, cardanol-cyanate ester (1-cyanato-3-pentadecylbenzene, CardCy) and cis-resveratrol-cyanate ester (cis-3,4’,5-tricyanatostilbene, cisResCy), respectively, were synthesized from biobased cardanol and resveratrol. The cisResCy monomer was blended with varying weights of CardCy and co-cured to produce five polycyanurate networks. The organic polymers displayed outstanding thermal stability and enhanced mechanical dampening.

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