Flame-Retardant Properties and Mechanism of Polylactic Acid-Conjugated Flame-Retardant Composites

Abstract

The DOPO derivative-conjugated flame retardant 4, 4'-{1'', 4'' - phenylene - bis [amino - (10‴ - oxy -10‴-hydro-9‴-hydrogen-10‴ λ5 -phosphaphenanthrene-10''-yl)-methyl]}-diphenol (P-PPD-Ph) with two hydroxyl groups was synthesized. Polylactic acid conjugated flame-retardant composites with P-PPD-Ph were papered by using a twin-screw extruder. The flame-retardant properties of polylactic acid-conjugated flame-retardant composites were investigated. The flame-retardant properties of PLA-conjugated flame-retardant composites were characterized by the limiting oxygen index (LOI) and the vertical burning test (UL94). The results showed that the PLA-conjugated flame-retardant composites achieved a V-0 rating (UL-94, 3.2 mm) when the conjugated flame retardant was added at 5 wt%, and increase in LOI value from 22.5% to 31.4% relative to composites without added conjugated flame retardant. The flame-retardant mechanism of PLA-conjugated flame-retardant composites were further studied by TG-FTIR, the results showed that the P-PPD-Ph promoted the PLA-conjugated flame-retardant composites to decompose and also released fragments with quenching and dilution, which suggests that P-PPD-Ph for PLA-conjugated flame-retardant composites mainly play a role of the gas-phase flame retardant.

Hierarchical PBO Nanofiber/PPS Melt-Blown Mats with a Controllable Porous Microstructure for Thermal Protection under Harsh Conditions

“…As shown in Figure c, when directly exposed to a burning flame, HNMM-2.0 exhibited excellent fire-retardant properties, without being burned, and no obvious volume shrinkage after being exposed for 60 s. By contrast, PPS-MBM was combusted and melted immediately (Figure S6). As can be seen from Figures d and S7, a layer of combustion residual carbon was formed on the surface of HNMMs, which would reduce the passage of flue gas, heat, and flame diffusion and act as a physical barrier to prevent further combustion inside HNMMs. − Furthermore, LOI was used to evaluate the flame retardance of HNMMs and PPS-MBMs quantitatively. The LOI of HNMM-2.0 was tested as 32, much higher than that of PPS-MBM (LOI = 26).…”

Flame retardant properties and mechanism of PLA/P-PPD -Ph /ECE conjugated flame retardant composites

“…P-PPD-Ph is a new type of DOPO-derived flame retardant with a high number of aromatic groups in its structure, which makes P-PPD-Ph have better thermal stability due to its conjugation and “cage effect” in the process of thermal degradation. The functional modification of PLA by adding flame retardants can improve its flame retardant properties, making PLA biodegradable material can be used in electronic and electrical appliances, automotive, construction, textile and other fireproof products ( Chokwe et al, 2020 ; Sun et al, 2022 ; Zhang et al, 2022 ).…”

Flame-retardant properties and mechanism of LGF/PBT/DOPO-HQ-conjugated flame-retardant composites

“…Phosphorus is an effective flame-retardant element, and phosphorus-based flame retardants can thermally decompose and release phosphorus-containing reactive radicals (e.g., PO2-, PO-, and HPO-, etc.) in the gas phase when used ( Zhang et al, 2022a ; Zhang et al, 2022b ). The average reactivity of these radicals is 10 times that of Cl- and 5 times that of Br-, which can effectively trap hydroxyl and hydrogen radicals, terminate the radical segment, and prevent further thermal decomposition of polyester materials.…”