Chain Extension and Synergistic Flame-Retardant Effect of Aromatic Schiff Base Diepoxide on Polyamide 6/Aluminum Diethylphosphinate Composites

Abstract

A way to suppress the deterioration in mechanical properties of polyamide 6 (PA6) is required, especially with high loading of flame retardants in the matrix. In this study, a novel aromatic Schiff base diepoxide (DES) was synthesized. It exhibited an efficient chain extension effect on PA6 and a synergistic flame-retardant effect with aluminum diethylphosphinate (AlPi) for PA6. The PA6 composite with 16 wt.% AlPi only passed UL-94 V-0 rating at 1.6 mm thickness, while the combination of 1.5 wt.% DES with 13 wt.% AlPi induced PA6 to achieve a UL-94 V-0 rating at 0.8 mm thickness. The tensile, flexural, and Izod notched impact strengths were increased by 16.2%, 16.5%, and 24.9%, respectively, compared with those of V-0 flame-retarded PA6 composites with 16 wt.% AlPi. The flame-retarded mechanism of PA6/AlPi/DES was investigated by cone calorimetry and infrared characterization of the char residues and pyrolysis products. These results showed that DES had a synergistic effect with AlPi in condensed-phase flame retardation by promoting the production of aluminum phosphorus oxides and polyphosphates in the char residues.

Flame Retarding and Strengthening Poly(ethylene 2,5-furandicarboxylate-co-ethylene terephthalate) Using Phosphonate Containing Genistein

“…The TSP of all PEFT20 blends is increased evidently, and the incorporation of TGIC increases the TSP slightly. Diphenyl phosphonate tends to act in the gas phase, leading to more smoke release than that of the matrix . DPGE has two diphenyl phosphonate groups that may scavenge the free radical, but it also induces smoke.…”

“…The hydroxyl characteristic peak at 3077 cm −1 in DPGE is retained, suggesting that the hydroxyl next to the carbonyl group in genistein has not been replaced by a diphenylphosphonyl group. 33 The 1 H NMR, 31 P NMR, and FTIR spectra results indicate that DPGE has been synthesized successfully. In addition, the melting point of DPGE is 220 °C, indicating that it is melted during processing, which helps it to be dispersed in PEFT20 uniformly.…”

A novel organic‐inorganic flame retardant of ammonium polyphosphate chemically coated by Schiff base‐containing branched polysiloxane for polyamide 6

“…The 3D TG‐IR spectra and the relevant FTIR spectra of pyrolysis volatiles evolved from PA6, PA6/APP, and PA6/SP‐APP‐3 are plotted in Figure 9. It is evident that the typical pyrolysis volatiles of PA6 and its composites are water (H 2 O, 3800‐3600 cm −1 ), hydrocarbons (2945 cm −1 ), CO 2 (2352 cm −1 ), carbonyl compounds (1708 cm −1 , CO of caprolactam) and aromatic compounds (1493 cm −1 ) 15,29,30 . However, some different pyrolysis products are observed in PA6/APP and PA6/SP‐APP‐3 in contrast with PA6 such as PO containing compounds (1076 cm −1 ) ascribed to PO· free radicals and NH 3 (963 and 919 cm −1 ) owing to the addition of APP or SP‐APP.…”

Alloying synergistic flame retardant effect improving fire resistance and mechanical properties of polyamide 6

“…The research of Yang et al 18 achieved PA6 composites with low heat release rate and high smoke suppression by compounding POSS and ADP. Zhao et al 19 using the Schiff base‐containing structures (DES) with ADP to flame retardant PA6. 1.5wt.%DES and 13wt.%ADP with PA6 can pass the V‐0 rating of UL94 in 0.8 mm thickness and increase the tensile, flexural, and impact strength.…”