Synthesis of hexa-allylamino-cyclotriphosphazene as a reactive fire retardant for unsaturated polyesters

Improving the curing and flame retardancy of epoxy resin composites by multifunctional Si-containing cyclophosphazene derivatives

Novel star-like molecules containing P, N and Si with dual functions of flame retardance and curing promotion (abridged as HCCP–KH540) were successfully synthesized through the nucleophilic substitution reaction of hexachlorocyclotriphosphazene (HCCP) and 3-aminopropyltrimethoxysilane (KH540). HCCP–KH540 was incorporated with the matrix of epoxy resin (EP) to form a flame retardant composite abridged as E-HK. The activation energy of the curing reaction of the E-HK composite was reduced but the curing reaction rate was accelerated by HCCP–KH540. The E-HK composite with 30 phr content of HCCP–KH540 exhibited excellent flame retardancy with limiting oxygen index of 29.6% and V-1 rating in the vertical burning test as well as excellent thermal stability with a char yield of 23.77% at 700 °C, compared with only 8.64% for pure EP.

Novel star-like molecules containing P, N and Si with dual functions of flame retardance and curing promotion were synthesized through the nucleophilic substitution reaction of hexachlorocyclotriphosphazene and 3-aminopropyltrimethoxysilane.

Synthesis of a Cyclophosphazene Derivative Containing Multiple Cyano Groups for Electron-Beam Irradiated Flame-Retardant Materials

A cyclophosphazene derivative containing multiple cyano groups, denoted as hexa(4-cyanophenoxy)cyclotriphosphazene (CN-CP), was synthesized by a one-step nucleophilic substitution reaction for a phosphorus-nitrogen flame retardant. To meet the strict requirement of safe and environment-protective insulation materials, a series of composites based on low-density polyethylene-poly(ethylene-co-vinyl acetate) containing CN-CP/Mg(OH)₂/Al(OH)₃ organic-inorganic synergistic flame retardants was fabricated. High-energy electron beam irradiation was subsequently applied to obtain a halogen-free flame-retardant crosslinked system. The relationship between crosslinking degree and irradiation dose was studied, and crosslinking degrees ranging within 63-85% were obtained under 100-190 kGy. Furthermore, the effects of CN-CP filler and irradiation dose on the properties of the composites were carefully investigated. The maximum tensile stress and limiting oxygen index values of most composites irradiated by EB were more than 15 MPa and 28%. Results revealed that the obtained materials had excellent thermal and mechanical, flame-retardant, and insulation properties, thereby suggesting their promising prospects for wire and cable applications.

A Review on Synthesis, Structural, Flame Retardancy and Dielectric Properties of Hexasubstituted Cyclotriphosphazene

Hexachlorocyclotriphosphazene is a ring compound consisting of an alternating phosphorus and nitrogen atom with two chlorine substituents attached to the phosphorus atom. The six chlorine atoms attached to this cyclo compound can be substituted with any different nucleophile that leads to changes in different chemical and physical properties. The major topics that were investigated in this research are the flame retardancy and dielectric properties of cyclotriphosphazene compounds. Cyclotriphosphazene compounds have high potential to act as a flame retardant, and this compound consists of two active elements attributed to its high flame-retardant character. This compound also demonstrated good ability as a flame retardant due to its low toxicity and less smoke produced. In addition, cyclotriphosphazene compounds were also investigated for their dielectric properties. Cyclotriphosphazene has high potential in the electrical field since it has dielectric properties that can be widely studied in the investigation of any potential application. This review presented literature studies focused on recent research development and studies in the field of cyclotriphosphazene that focused on synthesis, structural, flame retardancy, and dielectric properties of hexachlorocyclotriphosphazene compounds.

Synthesis and spectroscopic characterizations of hexakis[(1-(4'-oxyphenyl)-3-(substituted-phenyl)prop-2-en-1-one)]cyclotriphosphazenes: their in vitro cytotoxic activity, theoretical analysis and molecular docking studies

The hexachlorocyclotriphosphaze compound (N₃P₃Cl₆, HCCP) was reacted with excess (E)-(1-(4'-oxyphenyl)-3-(substituted-phenyl)prop-2-en-1-ones (2-11) to produce hexakis[(1-(4-oxyphenyl)-3-(substituted-phenyl)prop-2-en-1-one)]cyclotriphosphazenes (CP 2-11). The structures of products (CP 2-11) were confirmed using elemental analysis, FT-IR, MS spectral analysis as well as ³¹P, ¹H and ¹³C-APT NMR techniques and their thermal properties determined by TGA and DSC techniques. The HOMO-LUMO energy gap and chemical reactivity identifiers were calculated and HOMO and LUMO images were viewed. According to the calculations, all the chemical potential values of CP 2-11 are negative and it shown that the molecules are stable. The in vitro cytotoxic of CP 2-11 investigated and their activity potentials were evaluated by molecular docking studies with Autodock Vina softwares. CP 2-11 compounds were found to demonstrate cytotoxic activity against human cancer cell lines (A2780, LNCaP and PC-3). The CP 2-11 compounds reduced the cell viability against all cancer cell lines in the range 36%-90% especially. The results showed that these compounds are powerful candidate molecules for pharmaceutical applications.

A Green Water-Soluble Cyclophosphazene as a Flame Retardant Finish for Textiles

Poly- and cyclophosphazenes are excellent flame retardants but currently, are not used as textile finishing agents because water-soluble and permanent washing systems are missing. Here, we demonstrate for the first time, the successful usage of a water-soluble cyclotriphosphazene derivative for textile finishing for cotton, different cotton/polyester, and cotton/polyamide blend fabrics. A durable finish was achieved using a photoinduced grafting reaction. The flame retardant properties of the various fabrics were improved with a higher limiting oxygen index, a reduced heat release rate, and an exhibition of intumescent. Furthermore, the finished textiles passed several standardized flammability tests.

Study of the flame retardancy and thermal properties of unsaturated polyester resin via incorporation of a reactive cyclic phosphorus-containing monomer

A reactive cyclic phosphorus-containing monomer (ethyl acrylate cyclic glycol phosphate; EACGP) was synthesized in a facile way and various amounts of EACGP were combined with unsaturated polyester by radical bulk polymerization. The resulting flame-retardant unsaturated polyester resin (UPR) samples were investigated using thermogravimetric analysis, limiting oxygen index (LOI), and microscale combustion calorimetry tests. Due to the high phosphorus content of EACGP, incorporation of this monomer led to a marked decrease in the peak heat release rate and the total heat release, an increase in the LOI and the combustion char formation. Furthermore, real-time Fourier transform infrared spectroscopy was employed to investigate the thermooxidative degradation behavior of UPRs and the charring effect of EACGP as well as the UPR char morphology was studied, illustrating the flame retardancy mechanism in UPR.

Phosphorus-nitrogen compounds. Part 23: syntheses, structural investigations, biological activities, and DNA interactions of new N/O spirocyclotriphosphazenes

The Schiff base compounds (1 and 2) are synthesized by the condensation reactions of 2-furan-2-yl-methylamine with 2-hydroxy-3-methoxy- and 2-hydroxy-5-methoxy-benzaldehydes and reduced with NaBH(4) to give the new N/O-donor-type ligands (3 and 4). The monospirocyclotriphosphazenes containing 1,3,2-oxazaphosphorine rings (5 and 6) are prepared from the reactions of N(3)P(3)Cl(6) with 3 and 4, respectively. The reactions of 5 and 6 with excess pyrrolidine, morpholine, and 1,4-dioxa-8-azaspiro [4,5] decane (DASD) produce tetrapyrrolidino (5a and 6a), morpholino (5b and 6b), and 1,4-dioxa-8-azaspiro [4,5] deca (5c and 6c) spirocyclotriphosphazenes. The structural investigations of the compounds are examined by (1)H, (13)C, (31)P NMR, DEPT, HSQC, and HMBC techniques. The solid-state structures of 5, 5a, and 6 are determined using X-ray crystallography. The compounds 5a, 5b, 5c, 6a, 6b, and 6c are subjected to antimicrobial activity against six patojen bacteria and two yeast strains. In addition, interactions between these compounds and pBR322 plasmid DNA are presented by agarose gel electrophoresis.