scholarly journals EFFICIENT FLAME RETARDANTS FOR EPOXY RESINS: SYNTHESIS, STRUCTURE, PROPERTIES

Fire Safety ◽  
2020 ◽  
Vol 36 ◽  
pp. 101-107
Author(s):  
P. Pastuhov ◽  
V. Petrovskii ◽  
O. Lavrenyuk ◽  
B. Mykhalitchko

Introduction. In modern conditions, the combustibility of polymers plays a dominant role in the process of the appearance and spread of fires. This is because the extremely wide use of polymeric materials in all areas of the national economy. Due to the organic structure, the high content of carbon and hydrogen that make up the macromolecules of the polymers, they are extremely combustible. Combustion of polymers is accompanied by high temperature and flame propagation rate, as well as significant smoke generation and the release of a large number of toxic combustion products. Therefore, the search for new ways to reduce combustibility is one of the priority tasks in the creation and implementation of new polymer materials in various industries. Purpose. The aim of the work is the synthesis of fundamentally new complex compounds of transition metals, the study of their structure and properties, as well as predicting the possibility of their use to reduce the fire hazard of polymeric materials based on epoxy resins. Metods. Modern research methods are used in the work: X-ray diffraction, differential thermal and thermogravimetric analyzes, the method of quantum chemical calculations and IR spectroscopy. The ignition and self-ignition temperatures were determined by standard methods according to GOST 12.1.044-89 using metrologically certified equipment and calibrated measuring instruments. Results. By the direct interaction of the combustible organic amine pepa with inorganic salts of copper(II), a number of chelate complexes were obtained. By methods of x-ray phase analysis and IR spectroscopy, their structure was established. The results of quantum-chemical calculations of the complexation process showed that, as a result of the formation in the pepa–Cu(II) salt system, the chelate complexes [Cu(deta)H2O]SO4·H2O, [{Cu(deta)(H2O)(CO3)}2]·6H2O та [Cu(deta)(eda)]SiF6, the energy state of the chemically bonded pepa changes with respect to free molecules. In addition, the results of thermogravimetric studies and the measured ignition and self-ignition temperatures for pepa and complex compounds clearly showed that the process of bonding a combustible organic amine with a non-combustible inorganic salt into a solid complex ensures a decrease in the combustibility of nitrogen-containing hydrocarbon. All this is an extremely important prerequisite in the implementation of the complex mechanism of flame retardant action of transition metal salts. Conclusion. The results of the studies showed that complex compounds based on transition metal salts, and in particular copper(II), can be successfully used as flame retardants that can effectively reduce the fire hazard of nitrogen-containing synthetic polymers, including those based on epoxy resins.

2021 ◽  
Vol 7 (8) ◽  
pp. 110
Author(s):  
Songjie Yang ◽  
Matteo Zecchini ◽  
Andrew Brooks ◽  
Sara Krivickas ◽  
Desiree Dalligos ◽  
...  

The syntheses of new BEDT-TTF derivatives are described. These comprise BEDT-TTF with one ethynyl group (HC≡C-), with two (n-heptyl) or four (n-butyl) alkyl side chains, with two trans acetal (-CH(OMe)2) groups, with two trans aminomethyl (-CH2NH2) groups, and with an iminodiacetate (-CH2N(CH2CO2−)2 side chain. Three transition metal salts have been prepared from the latter donor, and their magnetic properties are reported. Three tris-donor systems are reported bearing three BEDT-TTF derivatives with ester links to a core derived from benzene-1,3,5-tricarboxylic acid. The stereochemistry and molecular structure of the donors are discussed. X-ray crystal structures of two BEDT-TTF donors are reported: one with two CH(OMe)2 groups and with one a -CH2N(CH2CO2Me)2 side chain.


2014 ◽  
Vol 69 (11-12) ◽  
pp. 1429-1440
Author(s):  
Markus Granitzka ◽  
Peter Stollberg ◽  
Dietmar Stalke

Abstract Bis-2-thienyldiethylaminophosphane (C4H3S)2PNEt2 (1) is introduced as a ligand for late transition metal complexes ([(H3C4S)2PNEt2]nMXmLp), with M = Ni(II), Au(I), Cu(I), Pd(II), Ir(I), X = Cl, Br and L = NCMe, COD, (2-7). Reactions of 1 with the late transition metal salts NiCl2·dme, (Me2S)AuCl, CuCl, PdCl2(PhCN)2, and [Ir(COD)Cl]2 yield the complexes [{(H3C4S)2PNEt2}2 · NiCl2] (2), [(H3C4S)2PNEt2 · AuCl] (3) [(H3C4S)2PNEt2·CuCl(CH3CN)]2 (4), [{(H3C4S)2PNEt2}2 · PdCl2] (5), [{(H3C4S)2PNEt2}2·PdCl2]2 (6), and [(H3C4S)2PNEt2·IrCl(COD)] (7). In addition, the transformation of 1 to the valuable chlorine-substituted starting material (H3C4S)2PCl (8) and the related conversion of 8 to the secondary phosphane (H3C4S)2PH (9) is reported. The complexes 2-7 are stable under inert gas conditions and were characterized by single-crystal X-ray studies, NMR spectroscopy, and elemental analysis.


2017 ◽  
Vol 4 (12) ◽  
pp. 171064 ◽  
Author(s):  
Corey L. Jones ◽  
Elizabeth A. Marsden ◽  
Adam C. Nevin ◽  
Benson M. Kariuki ◽  
Mohan M. Bhadbhade ◽  
...  

A series of new group 2 coordination polymers, MgL  ={MgL(H 2 O)(DMF) 0.75 } ∞ , CaL  = {CaL(DMF) 2 } ∞ , SrL  = {SrL(H 2 O) 0.5 } ∞ and BaL  = {BaL(H 2 O) 0.5 } ∞ , were synthesized using a flexible benzimidazolone diacetic acid linker ( H 2 L ) in which the two carboxylic acid binding sites are connected to a planar core via {–CH 2 –} spacers that can freely rotate in solution. In a ‘curiosity-led' diversion from group 2 metals, the first row transition metal salts Mn 2+ , Cu 2+ and Zn 2+ were also reacted with L to yield crystals of MnL = {MnL(DMF)(H 2 O) 3.33 } ∞ , Cu 3 L 2  = {Cu 3 L 2 (DMF) 2 (CHO 2 ) 2 } ∞ and ZnL  = {ZnL(DMF)} ∞ . Crystal structures were obtained for all seven materials. All structures form as two-dimensional sheets and contain six-coordinate centres, with the exception of ZnL, which displays tetrahedrally coordinated metal centres, and Cu 3 L 2 , which contains square planar coordinated metal centres and Cu paddle-wheels. In each structure, the linker adopts one of two distinct conformations, with the carboxylate groups either cis or trans with respect to the planar core. All materials were also characterized by powder X-ray diffraction and thermogravimetric analysis.


1998 ◽  
Vol 53 (9) ◽  
pp. 965-972 ◽  
Author(s):  
Markus Prem ◽  
Werner Bauer ◽  
Kurt Polbom ◽  
Wolfgang Beck

A series of chelate complexes 1-12 of Cu(II), Ni(II), Pd(II), and Ru(III) with the anion of 2-(2′-hydroxyphenyl)-5(4H)-oxazolone and with 2-(2′-aminophenyl)-5(4H)-oxazolone were prepared from metal salts or from chloro-bridged complexes [(R3P)MCl2]2 (M = Pd, Pt) and [(p-cymene)RuCl2]2. Nucleophilic addition of α-amino acid esters to the bis-chelate complexes M(oxophenyloxazolone)2(M = Ni, Cu) gave the dipeptide derivatives 13-18. Dinuclear Pd(II) and Pt(II) chelate complexes 19-23 were obtained from phenylene- and ethylenebridged bis(oxazolones). The structures of (Et3P)(Cl)Pd(O,N-oxophenyloxazolone) (6) and of Cl2(Et3P)Pt(2,2′-phenylene-bis(4-methyloxazolone)Pt(PEt3)Cl2 (20) were determined by X-ray diffraction. In complex 20 a close proximity of two phenylene H atoms to the metal is observed.


Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3901 ◽  
Author(s):  
Markwart ◽  
Battig ◽  
Velencoso ◽  
Pollok ◽  
Schartel ◽  
...  

The current trend for future flame retardants (FRs) goes to novel efficient halogen-free materials, due to the ban of several halogenated FRs. Among the most promising alternatives are phosphorus-based FRs, and of those, polymeric materials with complex shape have been recently reported. Herein, we present novel halogen-free aromatic and aliphatic hyperbranched polyphosphoesters (hbPPEs), which were synthesized by olefin metathesis polymerization and investigated them as a FR in epoxy resins. We compare their efficiency (aliphatic vs. aromatic) and further assess the differences between the monomeric compounds and the hbPPEs. The decomposition and vaporizing behavior of a compound is an important factor in its flame-retardant behavior, but also the interaction with the pyrolyzing matrix has a significant influence on the performance. Therefore, the challenge in designing a FR is to optimize the chemical structure and its decomposition pathway to the matrix, with regards to time and temperature. This behavior becomes obvious in this study, and explains the superior gas phase activity of the aliphatic FRs.


2021 ◽  
Vol 18 (2) ◽  
pp. 76-80
Author(s):  
Yu.A. Amelkovich ◽  

The disadvantage of polymeric materials, including epoxy resins, is their increased fire hazard. Reducing the flammability of polymeric materials is a serious problem that needs to be addressed. One of the ways to reduce the flammability of polymers is the introduction of special additives into the polymer matrix with flame retarding properties, which leads to a change in the nature of the processes occurring during the combustion of the polymer, or to blocking the combustion process with non-combustible or inhibiting substances. In this work, aluminum trihydroxide, melamine polyphosphate, and melamine poly(magnesium phosphate) were used as flame retardants to enhance the flame-resistant properties of epoxy resin. The filler loading in the epoxy composites was 10 wt. %. The experimental studies have been carried out to determine the ignition temperature of the produced epoxy composites. The data obtained were compared with the ignition temperature of a control sample of epoxy resin without filler. The results indicated that the incorporation of all the flame retardants studied resulted in an increase in the ignition temperature. The ignition temperature of the samples filled with melamine polyphosphate and melamine poly(magnesium phosphate) increased by 28 and 11 °C, respectively. However, the best result was obtained for a sample filled with aluminum trihydroxide: the ignition temperature of this sample was 40 °C higher than that of the unfilled epoxy resin.


1956 ◽  
Vol 102 (3) ◽  
pp. 632-635 ◽  
Author(s):  
H. P. Hanson ◽  
J. R. Knight

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