Heat-Resistant Polymer Networks Prepared from Processable Resveratrol-Based Propargyl Ether Monomers

Abstract

Three propargyl ether thermosetting resins were prepared from biosynthetic trans-resveratrol (1), cis-resveratrol (2), and dihydroresveratrol (3). The cure chemistry of the monomers as well as the thermal stability and mechanical properties of cross-linked networks were then characterized by techniques including differential scanning calorimetry, thermal gravimetric analysis, and dynamic mechanical analysis. The monomers were highly processable, existing as low melting solids (1, T m = 81 °C; 3, supercooled liquid with an ultimate T m = 40 °C), or a permanent room-temperature liquid (2). All three resins exhibited broad processing windows and high degrees of cure ranging from 97–99%. The glass transition temperatures (T g) of 1 and 2 were 389 and 384 °C (loss modulus), respectively, while 3 did not exhibit a well-defined T g. All three of the networks exhibited outstanding thermal stability with char yields of 66, 64, and 54% at 1000 °C (under N2) for 1, 2, and 3, respectively. Heat release capacities of 1, 2, and 3 were 53, 41, and 114 J g–1K–1, respectively, consistent with self-extinguishing (3) or non-ignitable (1, 2) polymers. The networks also exhibited low water uptakes ranging from 3.64 to 1.59 wt %. The thermal stability, fire-resistance, and mechanical properties of the resveratrol-based resins represent significant improvements over monomers derived from conventional petroleum-based bisphenols (e.g., bisphenol A). This work demonstrates that the unique morphology afforded by bio-based monomers allows for the preparation of polymer networks with enhanced properties. The resveratrol networks have potential applications as components of high-temperature and fire-resistant composite materials for aerospace applications.