Zirconium‐Embedded Polyhedral Oligomeric Silsesquioxane Containing Phosphaphenanthrene‐Substituent Group Used as Flame Retardants for Epoxy Resin Composites

Abstract

A zirconium hybrid polyhedral oligomeric silsesquioxane derivative (Zr-POSS-bisDOPO) is synthesized by the corner-capping and Kabachnik-Fields reactions. It is characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR), and then used as a flame retardant in diglycidyl ether of bisphenol A (DGEBA) to endow epoxy resin (EP) with flame retardancy. The flame retardancy, thermal stability, and mechanical properties of the cured EP/Zr-POSS-bisDOPO composites are investigated. The results show that when Zr-POSS-bisDOPO is added by 5-7 wt%, the EP/Zr-POSS-bisDOPO composites pass the UL-94 V-0 rating test. In addition, they have a better flame-retardant effect than pure EP. The combination of Zr atom embedded in the Si-O cubic cage and the two phosphaphenanthrene substituent groups in one corner of cubic cage is expected to realize the Zr/Si/P ternary intramolecular hybrid synergistic effect and achieve the possibility of dispersing metal-POSS cages at a sub-micrometer-scale level into polymer matrix. It also proves that Zr-POSS-bisDOPO produces phosphorus-containing free radicals and terminates the chain reactions in gas phase. Meanwhile the Si-O-Si and Zr-O units are retained in the solid phase, which promote the char formation and enhance the flame retardancy. This kind of Zr-doped POSS will be helpful for developing the new metal-POSS hybrid flame-retardant and polymer composites.

Cage-like manganesesilsesquioxanes: features of their synthesis, unique structure, and catalytic activity in oxidative amidations

“…[6][7][8][9][10][11][12][13][14][15][16] In addition to an enormous variety of CLMS nuclearities/molecular topologies, metallasilsesquioxanes are attractive candidates for applications in catalysis, [17][18][19][20] and designing new magnetic 21,22 or photoemissive materials. [23][24][25] In the context of materials chemistry, we could also mention the applicability of CLMSs to designing anodes for fast sodium storage, 26 flame retardants [27][28][29][30][31] and polyfunctional (SMM/luminescent) objects. 32 Surprisingly scarce information is available about manganese-based silsesquioxanes.…”

A Novel Family of Cage-like (CuLi, CuNa, CuK)-phenylsilsesquioxane Complexes with 8-Hydroxyquinoline Ligands: Synthesis, Structure, and Catalytic Activity

“…As a result, CLMSs offer an impressively wide scope of applications. These include the investigation of flame-retardant properties [ 25 , 26 , 27 , 28 , 29 , 30 ] and the development of approaches to anode [ 31 , 32 ] and ceramic [ 33 ] materials. Recent results revealed intriguing magnetic effects [ 34 , 35 ] (including the observation of spin glass [ 36 ] and single-molecule magnet [ 37 ] behaviors) and photophysical properties [ 38 , 39 , 40 , 41 , 42 , 43 , 44 ] of CLMSs.…”

Acetone Factor in the Design of Cu4-, Cu6-, and Cu9-Based Cage Coppersilsesquioxanes: Synthesis, Structural Features, and Catalytic Functionalization of Alkanes

“…The investigation of partly condensed POSS is also appealing, leading to the design of new monomers for copolymerization reactions, H-bond donor catalysts, OLED’s emission layers, three-dimensional emulsifiers, different films (e.g., transparent, scratch resistant, self-healing, or Langmuir–Blodgett/Langmuir–Schaefer films), and spin-on-glass networks with ultralow dielectric constants . By design, partly condensed polyhedral silsesquioxanes can be also regarded as versatile ligands for the construction of various cagelike metallacomplexes. − These intriguing compounds attract significant interest for the potential removal of radioactive elements, fabrication of flame retardants, − biomedical agents, luminescent materials, , or molecular magnets . Magnetic studies revealed rare cases of single-molecule magnets (SMMs), , spin glass, or spin–flip transition effects.…”