Intrinsic flame retardant phosphonate-based vitrimers as a recyclable alternative for commodity polymers in composite materials

Abstract

Vitrimers are a promising alternative to conventional composite materials as they can be recycled and reshaped but still need additives. Herein, intrinsic flame-retardant phosphorus-containing vitrimers are presented, which were used in composites.

Renewable and recyclable covalent adaptable networks based on bio-derived lipoic acid

“…However, the implementation of sustainable feedstocks is also needed in order to transition from petroleum-derived platform chemicals that have dominated the modern materials economy, including research in the CAN material space. 8 Progress on this front has relied on the derivatisation of bio-derived chemicals to enable dynamic bonding with the most common examples of bioderived CAN materials featuring imine [9][10][11][12][13][14][15][16] and epoxy [17][18][19][20][21][22][23] chemistries. On the other hand, the use of a renewably sourced monomer that possesses inherent dynamic functionality is a more attractive feature for next-generation CAN materials since synthetic costs could be mitigated and overall sustainability improved.…”

Phosphate Triester Dynamic Covalent Networks

“…Organo-phosphorus moieties, in polymeric materials, provide useful properties like antifouling, biodegradability, , flame retardancy, − and hyperbranching . A recent study utilized phosphonates in the polymeric backbone to get a flame-retardant vitrimer . However, to the best of our knowledge, bond exchange processes based on organo-phosphorus chemistry have not been implemented so far in DCNs.…”

Review on intrinsically recyclable flame retardant thermosets enabled through covalent bonds

“…Markwart et al used dynamic vinylogous polyurethane linkages and covalently bonded phosphonates as fire resistant units to create a recyclable fire resistant vitrimer before preparing a glass fiber‐reinforced composite 113 . The phosphorous containing thermoset named poly‐1 was chopped into tiny particles and put into a mold and hot‐pressed at 150°C for 30 min under 10 kN pressure, which was repeated several times, as displayed in Figure 19a.…”

“…(a) Recycling process of poly‐1; (b) THE versus PHRR/ t ig plot of poly‐1, standard poly‐2, neat epoxy resin and BDP combined epoxy resin; (c) PHRR against time plot of poly‐1, standard poly‐2, neat epoxy resin and BDP combined epoxy resin; (d) snapshot of poly‐1 char residues after cone calorimeter test 113 [Color figure can be viewed at wileyonlinelibrary.com]…”

“…Markwart et al used dynamic vinylogous polyurethane linkages and covalently bonded phosphonates as fire resistant units to create a recyclable fire resistant vitrimer before preparing a glass fiber-reinforced composite. 113 The phosphorous containing thermoset named poly-1 was chopped into tiny particles and put into a mold and hot-pressed at 150 C for 30 min under 10 kN pressure, which was repeated several times, as displayed in Figure 19a. Poly-1 had a storage modulus (G 0 ) of 0.36 GPa at 50 C, while nonphosphonate vitrimers named poly-2 had a storage modulus of 2.4 GPa at 50 C and showed similar properties after being repeated several times with poly-1.…”