Hexakis(4-nitrophenoxy) cyclotriphosphazene (HNTP) with ammonium polyphosphate (APP) were added to acrylonitrile–butadiene–styrene copolymer (ABS) to improve the intumescent flammability and thermal properties of ABS. The effect of intumescent flame retardancy was characterized by limited oxygen index (LOI), vertical burning test (UL-94), thermos gravimetric analysis (TGA) tests, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). When the loading of ABS, HNTP and APP were 70, 15 and 15%, respectively, the LOI value reached 25.6 and UL-94 test was V-0. The TGA showed the high char yield of ABS/30%HNTP system at high temperatures. The experimental and theoretical TG curves and FTIR indicated that HNTP and APP promoted the form of cross-link structure, which acted as a barrier near the surface of material. The SEM further revealed the formation morphology of intumescent charred layer on ABS/15%HNTP/15%APP system. Tensile tests provided the possibility of using HNTP at high temperature.

A series of flame-retarded epoxy resins (EP) loaded with methyl MQ silicone resin and a novel hyperbranched polysiloxane (HPSi) acting as compatibilizer have been prepared. Compatibility of these EP composites was characterized by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The results showed that HPSi significantly improved the compatibility of EP/MQ. The flame retardancy and thermal degradation behavior of these EP composites were investigated by limiting oxygen index (LOI), UL-94 vertical burning, themogravimetric analysis test (TG), FTIR and SEM. The results showed that the incorporation of MQ into EP can improve the thermal stability dramatically. It is observed that the LOI values of epoxy resins increased obviously (from 21% to 31%) with the MQ loading, which passed V-0 rating of UL-94. Specifically, its combustion residue at 700 °C was 14.5% weight, which exceed the value of neat EP resin (5.08% weight). Moreover, structural analysis of the remaining after vertical burning by FTIR spectra verified the formation of polyaromatic carbons. Additionally, morphology of the residue char showed the compact, smooth, and tight structure of EP composites systems. These outstanding integrated properties would make EP composites attractive for practical applications.

Hexakis(4-nitrophenoxy) cyclotriphosphazene (HNTP) and oligomeric bisphenol A bis(diphenyl phosphate) (BDP), phosphorous-containing flame retardant, were mixed into polycarbonate (PC) together as intumescent flame retardancy (IFR) system. The flame retardancy and thermal decomposition behavior of composites were studied with the limiting oxygen index(LOI), UL-94 vertical burning test, microscale combustion calorimeter(MCC) and thermogravimetric analysis(TGA). The results showed the LOI of IFR system increased by 1.68 times compared with pure PC. The addition of HNTP and BDP accelerated the first decomposition peak but weaken the second decomposition peak to improve the flame retardancy of PC. Furthermore, TGA coupled with fourier transform infrared(TGA/FTIR) was used to research the gaseous products. Scanning electron microscopy (SEM) analyses and FTIR spectroscopy were used to study the structure of residual char. The results showed that HNTP and BDP formed continuous bubbles on the surface of PC during burning and exhibited synergistic effects on thermal stability of PC.

A novel hyperbranched polysiloxane (HPSi) with a great amount of epoxy groups was synthesized as a compatibilizer of epoxy resin (EP)/methyl phenyl silicone resin (Si603) blends. The structure of HPSi has been analyzed by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H-NMR) spectroscopy. The compatibility of EP/HPSi/Si603/DDM was characterized by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM), and the results showed that HPSi significantly improved the compatibility of EP/Si603. The flame retardancy and thermal degradation behavior of the EP/HPSi/Si603/DDM systems were investigated using the limiting oxygen index (LOI), UL-94 vertical burning, thermogravimetric analysis (TG), FTIR and SEM. The LOI value of the modified EP resin with 10% HPSi and 30% Si603 was 31 (about 1.4 times the corresponding value of the original EP resin), and passed V-1 of the UL-94 rating. Specifically, its combustion residue at 800 °C was about 2.24 times that of the original EP resin. Moreover, structural analysis of the combustion residue by FTIR showed the formation of polyaromatic carbons. Additionally, the morphology of the residue char showed the compact, smooth, and tight structure of the EP/HPSi/Si603/DDM systems. Mechanical properties such as tensile strength, flexural strength and flexural modulus of EP/DDM and EP/HPSi/Si603/DDM systems were evaluated and the result showed that these polymers also possess good mechanical properties. These outstanding integrated properties would make EP/HPSi/Si603/DDM systems attractive for practical applications.

One stage halogen-free flame retardant was prepared by poly(p-ethylene terephthalamide) (PETA) or poly(para-phenylene terephthanlamide) (PPTA) and ammonium polyphosphate (APP), the system had a good flame retardancy on acrylonitrile-butadiene-styrene (ABS) resin when loading was 30% or more, but once mass fraction decreased, the system did not maintain previous flame retardancy. To improve the efficiency of this kind of flame retardant, we mixed PETA with PPTA and introduced red phosphorus to play as the second acid source. This system had two charring process—swell and shrink. The flammability and thermal stability of IFR-ABS composites were investigated by limiting oxygen index (LOI), UL-94 vertical burning and thermo gravimetric analysis (TGA) test. Results showed that this IFR system had both good flame retardant and anti-dripping abilities for ABS, when the mass fractions of APP, PETA, PPTA and red phosphorus were only 12%, 4%, 1.33% and 2.66% respectively, the LOI of flame retardant ABS was 27 and UL-94 vertical burning test reached V-0. The TGA curves suggested that there was a distinct cooperation. Additionally, the structure and the mechanism of charring were studied by FTIR and SEM.