Polymers derived from bio-renewable resources are finding an increase in global
demand. In addition, polymers with distinctive functionalities are required in certain
advanced fields, such as aerospace and civil engineering. In an attempt to meet both these
needs, the goal of this work aims to develop a range of bio-based thermosetting matrix
polymers for potential applications in multifunctional composites. Ring-opening
metathesis polymerization (ROMP), which recently has been explored as a powerful
method in polymer chemistry, was employed as a unique pathway to polymerize
agricultural oil-based reactants.
Specifically, a novel norbornyl-functionalized castor oil alcohol (NCA) was
investigated to polymerize different cross-linking agents using ROMP. The effects of
incorporating dicyclopentadiene (DCPD) and a norbornene-based crosslinker (CL) were
systematically evaluated with respect to curing behavior and thermal mechanical
properties of the polymers. Isothermal differential scanning calorimetry (DSC) was used
to investigate the conversion during cure. Dynamic DSC scans at multiple heating rates
revealed conversion-dependent activation energy by Ozawa-Flynn-Wall analysis. The
glass transition temperature, storage modulus, and loss modulus for NCA/DCPD and
NCA/CL copolymers with different cross-linking agent loading were compared using
dynamic mechanical analysis. Cross-link density was examined to explain the very
different dynamic mechanical behavior. Mechanical stress-strain curves were developed
through tensile test, and thermal stability of the cross-linked polymers was evaluated by
v
thermogravimetric analysis to further investigate the structure-property relationships in
these systems.