No abstract

The flammability and melt dripping of the widely used bio-based polyamide 11 (PA 11) have attracted much attention in the last decade, and they are still a big challenge for the fire science society. In this work, a novel single macromolecular intumescent flame retardant (AM-APP) that contains an acid source and a gas source was prepared by supramolecular reactions between melamine and p-aminobenzene sulfonic acid, followed by an ionic exchange with ammonium polyphosphate. The chemical structure of AM-APP was characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. AM-APP and TiO were then introduced into PA 11 by melt compounding to improve the fire resistance of the composite. The fire performance of PA 11 composites was evaluated by the limiting oxygen index (LOI), vertical burning (UL-94), and cone calorimetry tests. The results showed that the presence of 22% AM-APP and 3% TiO increased the LOI value from 22.2 to 29.2%, upgraded the UL-94 rating from no rating to V-0, completely eliminated melt dripping, and significantly decreased the peak heat release rate from 943.4 to 177.5 kW/m. The thermal behaviors were investigated by thermogravimetric (TG) analysis and TG-FTIR. It is suggested that AM-APP produces an intumescent char structure and releases inert gases, whereas TiO may consolidate the char layers, leading to the improvement in the fire resistance of PA 11.

No abstract

No abstract

In this work, a bio‐based flame retardant, casein, was incorporated into poly(lactic acid) (PLA) matrix by melt compounding in order to improve the fire resistance and sustain the biodegradable character of PLA simultaneously. The fire performance of PLA composites was evaluated by limiting oxygen index, UL‐94 vertical burning, and cone calorimeter tests, respectively. The results indicated that the introduction of 20% casein increased the limiting oxygen index value of PLA composites from 20.0% to 32.2%, upgraded the UL‐94 rating from no rating to V‐0, and decreased the peak heat release rate from 779 to 639 kW/m2. The decomposition products of PLA composites were analyzed by Fourier transform infrared, and the morphology of the char after combustion was observed by scanning electron microscopy. It was suggested that casein took effects in both gas phase by releasing non‐flammable gases (such as NH3 and H2O) and condensed phase by the formation of protective char layers. However, the presence of casein in PLA induced an unavoidable deterioration in the mechanical performance. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46599.