Synergy between piperazine pyrophosphate and aluminum diethylphosphinate in flame retarded acrylonitrile-butadiene-styrene copolymer

• Published in: Polymer degradation and stability Vol. 190; p. 109639
• Main Authors: Yuan, Zha, Wen, Hui, Liu, Yuan, Wang, Qi
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01.08.2021; Elsevier BV
• Subjects: ABS; ABS resins; Acrylonitrile butadiene styrene; Aluminum; Aluminum diethylphosphinate; calorimeters; composite polymers; Cone calorimeters; Copolymers; degradation; Dilution; Flame retardant; Flame retardants; Flammability; Fourier transform infrared spectroscopy; Fourier transforms; FTIR spectrometers; Infrared analysis; Infrared spectroscopy; Lewis acid; Melt blending; oxygen; Photoelectrons; piperazine; Piperazine pyrophosphate; Scanning electron microscopy; spectrometers; Spectroscopic analysis; Styrenes; synergism; Synergy; Thermal stability; Thermogravimetric analysis; thermogravimetry; X ray photoelectron spectroscopy; Flame retardant; Aluminum diethylphosphinate; ABS; Piperazine pyrophosphate; Synergy
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/j.polymdegradstab.2021.109639

lPiperazine pyrophosphate and aluminum diethylphosphinate were introduced to ABS as effective halogen-free flame retardants.lThe PAPP/AlPi mixture with a 4:1 mass ratio presented an optimum synergy.lThe Lewis acid-base interactions between PAPP and AlPi resulted in a char layer with superior barrier effect. Acrylonitrile-butadiene-styrene (ABS) copolymer was combined with piperazine pyrophosphate (PAPP) and aluminum diethylphosphinate (AlPi) to prepare the flame retarded ABS (FRABS) composites by melt blending method. The PAPP/AlPi mixture with a mass ratio of 4:1 achieved an optimum synergy at a 25 wt.% flame retardant loading. The relevant composite (FRABS-3) reached the UL-94 V-0 rating (3.2 mm) and got a limiting oxygen index (LOI) of 30.8%. The synergistic flame retardancy mechanism of PAPP and AlPi was investigated using thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analyzer coupled with an FTIR spectrometer (TG-FTIR), cone calorimeter test (CCT), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS). The synergism is based primarily on the Lewis acid-base interactions between PAPP and AlPi. The interactions lead to the formation of a cohesive, uniform, and thermally stable char layer before ABS starts to decompose. The barrier effect of the high-quality char layer plays a dominant role in reducing the flammability of FRABS-3. Furthermore, fuel dilution and flame inhibition effects of the evolved gases also contribute to the superior flame retardancy of FRABS-3 to some extent.