Co-curing preparation of flame retardant and smoke-suppressive epoxy resin with a novel phosphorus-containing ionic liquid

A multi‐element flame retardant for rail transit to improve the flame retardant performance of epoxy resin while reducing smoke density

“…At the same time, the ester group CO bond was found in DTBD in 1667 cm −1 indicating that 3,5‐diaminobenzoic acid and benzaldehyde were involved in the reaction. The PH bond corresponding to the 2450 cm −1 absorption peak in DOPO does not exist in DTBD, 21–25 and the PO bond is found in 1250 cm −1 in DTBD, indicating that the addition reaction between the intermediate and DOPO has completely occurred.…”

In Situ-Generated Heat-Resistant Hydrogen-Bonded Organic Framework for Remarkably Improving Both Flame Retardancy and Mechanical Properties of Epoxy Composites

“…On the basis of the above analysis, a diagram of the possible flame-retardant mechanism is speculated, as shown in Figure . In the condensed phase, HOF-FJU-1 has excellent char formation properties, which facilitates the rapid formation of the char layer in the combustion process . At the same time, due to the unique pore structure of HOF-FJU-1, the pyrolysis volatiles and heat must be released through a more complex pathway than the usual one, which is known as the “labyrinth effect” .…”

“…In the condensed phase, HOF-FJU-1 has excellent char formation properties, which facilitates the rapid formation of the char layer in the combustion process. 66 At the same time, due to the unique pore structure of HOF-FJU-1, the pyrolysis volatiles and heat must be released through a more complex pathway than the usual one, which is known as the "labyrinth effect". 45 In addition, the high degree of graphitization of the char layer slows down the transfer of oxygen and heat to the internal matrix.…”

Solvent-Free Synthesis of a Hyperbranched Polyphosphoramide Cocuring Agent and Its Application in Fire-Safe, Mechanically Strong, and Tough Epoxy Resin

“…20−22 In addition, the precise design of terminal groups (e.g., −OH, −NH 2 , etc.) of HBPs can impart HBPs with cocuring properties, 23 allowing HBPs to be bonded with the epoxy chains by the chemical bonds to construct a tightly cross-linking network, which is conducive to solving the pain points for poor flame-retardant durability of small molecular FRs. 24,25 Because the aggregation of HBPs is caused by intermolecular hydrogen bonding and HBPs participate in the curing reaction, HBPs with cocuring properties can construct a supramolecular/polymer interpenetrating network in the EP matrix.…”

“…The impact energy can be dissipated by the free volume provided by intramolecular cavities of HBPs, which is beneficial for making EP composites tougher. − In addition, the precise design of terminal groups (e.g., −OH, −NH 2 , etc.) of HBPs can impart HBPs with cocuring properties, allowing HBPs to be bonded with the epoxy chains by the chemical bonds to construct a tightly cross-linking network, which is conducive to solving the pain points for poor flame-retardant durability of small molecular FRs. , Because the aggregation of HBPs is caused by intermolecular hydrogen bonding and HBPs participate in the curing reaction, HBPs with cocuring properties can construct a supramolecular/polymer interpenetrating network in the EP matrix . Thus, the rational design of rigid and flexible chains for HBP with the reactive terminal groups is able to construct a highly flexible and cross-linking interpenetrating network in the EP matrix, which is expected to endow EP composites with outstanding strength and toughness .…”