An efficient halogen-free flame retardant for glass-fibre-reinforced poly(butylene terephthalate)

et al. 2018

Polymer Composites

Poly(butylene terephthalate) (PBT)/10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-HQ) composites with poly(ethylene-butylacrylate-glycidylmethacrylate) (PTW) as a compatibilizer were prepared by the twin-screw extruder. The flame retardant and thermal decomposition mechanism of the PBT/DOPO-HQ flame retardant composites was investigated. The limiting oxygen index (LOI), vertical burning test (UL94), cone calorimetric test, thermogravimetric analysis, laser micro-Raman spectrometer (LRS), thermogravimetric analysis-Fourier transform infrared spectrometer, and TG-differential scanning calorimetry of the PBT/DOPO-HQ flame retardant composites were carried out. The LOI results showed that the LOI value PBT/ DOPO-HQ flame retardant composites with PTW compatibilizer is higher than PBT/DOPO-HQ flame retardant composites without PTW compatibilizer. The PBT/PTW/ DOPO-HQ (20%) flame retardant composites achieved UL-94 V-0 classification, but only addition of 20% DOO-HQ to PBT just achieved vertical burning test (UL94) V-2 classification with serious flammable dripping. What's more, the mechanical properties of PBT/DOPO-HQ flame retardant composites were studied. POLYM. COMPOS., 00:000-000,

Section: Resultssupporting

confidence: 93%

Flame retardant and thermal decomposition mechanism of poly(butylene terephthalate)/DOPO‐HQ composites

Zhang

et al. 2018

Polymer Composites

“…Generally, the intumescent char layer slowed down the heat and mass transfer between the gas and solid phases, consequently providing an improved flame shield for the underlying material during combustion. 29,30 These results indicated that the EG could further promote the high-quality intumescent char formation.…”

Section: Resultsmentioning

confidence: 86%

Flame retardancy and toughening properties of epoxy composites containing ammonium polyphosphate microcapsules and expanded graphite

High Performance Polymers

Gou

et al. 2017

Ammonium polyphosphate microcapsules (BM (polybenzoxazine modified) APP) were prepared through the in situ ring-opening polymerization of allyl group containing benzoxazine monomers on the surfaces of ammonium polyphosphate (APP), and they were significantly hydrophobic than the APP. A flame retardant system of epoxy (EP) resin was prepared with BMAPP and expanded graphite (EG). Flame retardancy, the thermal degradation behavior, a mechanical property of EP and EP/BMAPP/EG composites was investigated through limited oxygen index, vertical burning test, cone calorimetry (CONE), and the thermogravimetric analysis (TGA). The flame retardancy tests indicated that the EG could improve the thermal performance, promote the charring, and enhance the char quality of EP/BMAPP. Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) were employed to analyze the morphology and composition of the char residue formed during CONE testing, and to understand the mechanism of char formation. The results of TG-FTIR confirmed the possible mechanism of flame retardancy of EP/BMAPP/EG in the gas phase during combustion. The EG content effects on Young’s modulus, the tensile strength, and the fracture toughness ( KIC) of the EP/BMAPP composites were also investigated. The KIC of the composites containing 1% of EG and 10% of BMAPP increased by approximately 76% and 153%, respectively, compared to the neat matrix and EP/BMAPP-10%. The SEM images of the fractured surface indicated that the enhanced toughness of EP/BMAPP/EG composites mainly attributed to the debonding of the BMAPP and the subsequent plastic void growth of the matrix, as well as the crack deflection effect of the BMAPP/EG.

“…Generally, the intumescent char layer could slow down the heat and mass transfer between the gas and solid phases, so it can provide better flame shield for the underlying material during combustion [26][27] . As a result, compared with EP/CSP PS-APP -20% composite, EP/CSP PS-APP -15% has a better quality intumescent char corresponding to a higher LOI value, a lower HRR, and better flame retardant properties.…”

Section: Thermal Properties Of Ep and Ep/csp Ps-app Compositesmentioning

confidence: 99%

Flame retardant and toughening mechanisms of core–shell microspheres

Wang

et al. 2015

RSC Adv.

Epoxy (EP) composites containing polystyrene-ammonium polyphosphate core-shell microspheres (CSP PS-APP ) were developed for flame retardant and toughening effects. The flame retardancy and thermal degradation behavior of the EP composites was investigated by limited oxygen index (LOI), vertical burning test (UL-94), cone calorimeter (CONE) and thermogravimetric analysis (TGA). Scanning electron microscope with energy-dispersive spectroscopy capability (SEM-EDS) was used to characterize the morphology and elements of the residual chars. A possible flame retardant mechanism of CSP PS-APP in EP matrix was proposed based on the CONE, TGA and SEM-EDS results. The influence of CSP PS-APP content on the glass transition temperature (T g ), storage modulus, Young's modulus, tensile strength and fracture toughness (K IC ) of material was also investigated. The results show that the CSP PS-APP microspheres lead to significant flame retardant and char formation effects on the EP. The Young's modulus and fracture toughness of EP/CSP PS-APP composites increase with increasing CSP PS-APP content. The fracture toughness of the composite containing 15% CSP PS-APP increased by approximately 59% compared to that of neat matrix. In addition, the critical strain energy release rate (G IC ) of the epoxy increased from 159 to 409 J.m -2 with the addition of 15% CSP PS-APP . The SEM images of fracture surface indicate that the enhanced toughness of EP/CSP PS-APP composites can be attributed to the debonding of the core-shell 2 microspheres and the subsequent plastic void growth of the matrix, as well as the crack deflection effect of CSP PS-APP .