Porous thermosets via hydrolytic degradation of poly(ε-caprolactone) fragments in cyanurate-based hybrid networks

Synthesis, morphology, and thermal stability of nanoporous cyanate ester resins obtained upon controlled monomer conversion

“…First, non-extracted CER samples did not exhibit any porous structure (see supplementary material), as shown in our previous reports [10,11]. As expected, for the CER1 sample (with the lowest final degree of OCN conversion) after extraction, a nanoporous structure with the highest porosity ratio equal to 7.4% was found (cf.…”

“…Recently, we have reported on several novel approaches for producing nanoporous CER films via selective alkaline hydrolysis or partial extraction of reactive poly(-caprolactone) (PCL) sub-chains from CER/PCL hybrid networks [10,11]. During the synthesis of PCL-modified CER films, partial incorporation of the reactive modifier into CER crosslinked structures was found through condensation reactions of terminal hydroxyl groups from PCL with cyanate groups of growing CER networks [12].…”

“…Nanoporous frameworks were then derived from such CER/PCL-based hybrid networks by hydrolysis of a significant part of PCL sub-chains under mild conditions [10]. Since a non-negligible part of PCL oligomers was not chemically incorporated into the network structure, we developed an alternative and easier route to generate nanopores in films of CER/PCL hybrid networks by mere removal of free unreacted PCL through acetone extraction [11].…”

Effect of ionic liquids on kinetic parameters of dicyanate ester polycyclotrimerization and on thermal and viscoelastic properties of resulting cyanate ester resins

“…Obviously enough, Figure 10 shows the temperature dependence of storage modulus (E′) and loss factor (tan δ) for neat CER and CER/IL networks. All the samples were characterized by high α relaxation temperature values (T α > 240°C, Table 4), as typically found for thermostable cross-linked polymers, due to high temperature resistance of cross-links and high cross-linking density of polymer networks [1][2][3][4][5][6][32][33][34][35]. Unpredictably, a significant effect of the low IL content (i.e., 1.0 wt%) on the viscoelastic properties of all CER/IL networks was found compared to those of pure CER ( Figure 10, Table 4).…”

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Cyanate ester resins (CERs) represent a family of thermosetting polymers possessing attractive intrinsic features, such as excellent dimensional stability, high glass transition temperature (T g > 250°С), low dielectric constants (2.5-3.2), flame-retardancy, and high adhesion to conductor metals and composites. Therefore, they are promising materials for aerospace and microelectronic applications, especially as polymer matrices for structural composites, adhesives, potting resins, and coatings that work under severe conditions (high temperature, humidity, corrosive media, etc) [1][2][3][4][5][6]. Dicyanate ester monomers undergo thermal polycyclotrimerization to generate high T g polycyanurate networks (PCNs), i.e.

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