Effect of Ammonium Polyphosphate to Aluminum Hydroxide Mass Ratio on the Properties of Wood-Flour/Polypropylene Composites

Synergistic Flame Retardant Effect of Barium Phytate and Intumescent Flame Retardant for Epoxy Resin

Recently, widespread concern has been aroused on environmentally friendly materials. In this article, barium phytate (Pa-Ba) was prepared by the reaction of phytic acid with barium carbonate in deionized water, which was used to blend with intumescent flame retardant (IFR) as a flame retardant and was added to epoxy resin (EP). Afterward, the chemical structure and thermal stability of Pa-Ba were characterized by Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA), respectively. On this basis, the flammability and flame retardancy of EP composites were researched. It is shown that EP/14IFR/2Ba composite has the highest limiting oxygen index (LOI) value of 30.7%. Moreover, the peak heat release rate (PHRR) of EP/14IFR/2Ba decreases by 69.13% compared with pure EP. SEM and Raman spectra reveal the carbonization quality of EP/14IFR/2Ba is better than that of other composites. The results prove that Pa-Ba can cooperate with IFR to improve the flame retardancy of EP, reducing the addition amount of IFR in EP, thus expanding the application range of EP. In conclusion, adding Pa-Ba to IFR is a more environmentally friendly and efficient method compared with others.

Mechanical and Fire Properties of Multicomponent Flame Retardant EPDM Rubbers Using Aluminum Trihydroxide, Ammonium Polyphosphate, and Polyaniline

In this study, multicomponent flame retardant systems, consisting of ammonium polyphosphate (APP), aluminum trihydroxide (ATH), and polyaniline (PANI), were used in ethylene propylene diene monomer (EPDM) rubber. The multicomponent system was designed to improve flame retardancy and the mechanical properties of the rubber compounds, while simultaneously reducing the amount of filler. PANI was applied at low loadings (7 phr) and combined with the phosphorous APP (21 phr) and the mineral flame retardant ATH (50 phr). A comprehensive study of six EPDM rubbers was carried out by systematically varying the fillers to explain the impact of multicomponent flame retardant systems on mechanical properties. The six EPDM materials were investigated via the UL 94, limiting oxygen index (LOI), FMVSS 302, glow wire tests, and the cone calorimeter, showing that multicomponent flame retardant systems led to improved fire performance. In cone calorimeter tests the EPDM/APP/ATH/PANI composite reduced the maximum average rate of heat emission (MARHE) to 142 kW·m-2, a value 50% lower than that for the unfilled EPDM rubber. Furthermore, the amount of phosphorus in the residues was quantified and the mode of action of the phosphorous flame retardant APP was explained. The data from the cone calorimeter were used to determine the protective layer effect of the multicomponent flame retardant systems in the EPDM compounds.

Improved Flame-Retardant and Ceramifiable Properties of EVA Composites by Combination of Ammonium Polyphosphate and Aluminum Hydroxide

Ceramifiable flame-retardant ethylene-vinyl acetate (EVA) copolymer composites for wire and cable sheathing materials were prepared through melt compounding with ammonium polyphosphate (APP), aluminum hydroxide (ATH) and fluorophlogopite mica as the addition agents. The effects of ammonium polyphosphate, alumina trihydrate, and APP/ATH hybrid on the flame retardant, as well as on the thermal and ceramifiable properties of EVA composites, were investigated. The results demonstrated that the composites with the ratio of APP:ATH = 1:1 displayed the best flame retardancy and the greatest char residues among the various EVA composites. The tensile strength of the composites was 6.8 MPa, and the residue strength sintered at 1000 °C reached 5.2 MPa. The effect of sintering temperature on the ceramifiable properties, microstructures, and crystalline phases of the sintered specimen was subsequently investigated through X-ray diffraction, Fourier transform infrared, and scanning electron microscopy. The XRD and FTIR results demonstrated that the crystal structure of mica was disintegrated, while magnesium orthophosphate (Mg₃(PO₄)₂) was simultaneously produced at an elevated temperature, indicating that the ceramization of EVA composites had occurred. The SEM results demonstrated that a more continuous and compact microstructure was produced with the rise in the sintering temperature. This contributed to the flexural strength improvement of the ceramics.

Combination of Magnetic Lignocellulosic Particles, High-Density Polyethylene, and Carbon Black for the Construction of Composites with Tunable Functionalities

Biocomposites with unique functionalities for tailored applications are promising products for a sustainable future. In this work, a process concept of forming functional composites by combining of high-density polyethylene, carbon black, and magnetic lignocellulosic particles (wood flour) was demonstrated. The impacts of process parameters on morphologies, crystalline phase, and magnetic intensity of wood flour were identified. Magnetic, antistatic and mechanical properties of biocomposites were also evaluated. Lignocellulosic particles were encapsulated with magnetic nanoparticles, and the resulting composites exhibited tunable magnetic and antistatic properties. A noticeable feature is that magnetic nanoparticles were uniformly distributed in the matrices as a result of anchorage to lignocellulosic particles. Magnetic lignocellulosic particles and polymer resin had good compatibility. The resulting composites provided another opportunity for shielding materials, which could reduce the radiation in the living environment. These findings could provide a tunable strategy of the tailored use of lignocellulose-based composites in functional applications.