Fabrication and Mechanism Study of Cerium-Based P, N-Containing Complexes for Reducing Fire Hazards of Polycarbonate with Superior Thermostability and Toughness

Abstract

A superior comprehensive performance is essential for the extensive utilization of polymers. Current flame-retardant strategies for polycarbonates (PCs) usually realize satisfied fire resistance at the cost of thermostability, toughness, and/or mechanical robustness. Thus, we report a rare-earth-based P, Ncontaining complex with a lamellar aggregated structure [Ce-(DPA) 3 ] by a coordination reaction between a tailored ligand and cerium(III) nitrate. The results indicate that incorporating 3 wt % Ce(DPA) 3 enables the resultant PC composite to achieve UL-94 V-0 rating, with a 55% reduction in the peak heat release rate. Besides, the initial (T 5 ) and maximum (T max1 and T max2 ) decomposition temperatures are significantly increased by 21, 19, and 27 °C, respectively, in an air atmosphere. Moreover, the impact strength and elongation at break of the PC composite containing 3 wt % Ce(DPA) 3 are greatly increased by 20 and 59%, respectively, relative to pristine PC, while its tensile strength (57 MPa) is still close to that of bulk PC (60 MPa). Notably, this work provides a novel methodology for revealing the evolution mechanisms of chemical structures of vapor and residual products during thermal decomposition, which is conducive to guiding fire and heat resistance modification of PC in the future.

A novel lanthanum‐based phosphorus‐containing flame retardant agent and its application in polylactic acid

“…In the gas phase, NH 3 and H 2 O diluted oxygen and combustible gases to suppress the combustion process 11,51 . La@DDP released phosphorus‐containing radicals during the thermal decomposition process, which interrupted and inhibited the combustion by quenching the active radicals, which originate from PLA chain scission, thereby slowing down the degradation process of the polymer 26,52,53 . Therefore, continuous, and highly dense graphitized residual char was produced under the dual action of condensed phase and gas phase flame retardant.…”

“…11,51 La@DDP released phosphoruscontaining radicals during the thermal decomposition process, which interrupted and inhibited the combustion by quenching the active radicals, which originate from PLA chain scission, thereby slowing down the degradation process of the polymer. 26,52,53 Therefore, continuous, and highly dense graphitized residual char was produced under the dual action of condensed phase and gas phase flame retardant. This significantly hinders the transfer of heat and substances, and ultimately slows down the combustion process.…”

Recent advances in fire‐retardant carbon‐based polymeric nanocomposites through fighting free radicals

“…However, at high loading levels of IFR, the presence of PMGO does not contribute to the thermal stability of PP in air condition. Similarly, there were huge amount of efficient flame‐retardant nanocomposites fabricated by dual‐phase free‐radical capturers successfully 140–149 . Therefore, these dual‐phase hybrid free‐radical capturers often possess a higher fire‐retardant efficiency than the condensed‐phase ones.…”

“…Similarly, there were huge amount of efficient flame-retardant nanocomposites fabricated by dual-phase free-radical capturers successfully. [140][141][142][143][144][145][146][147][148][149] Therefore, these dual-phase hybrid free-radical capturers often possess a higher fire-retardant efficiency than the condensed-phase ones.…”

A silicone diphenylsulfonate for improving the flame retardancy of polycarbonate

“…So far, a variety of flame retardants (FRs) suitable for PC have been reported, and include compounds containing bromine, 4,5 phosphorus, 6,7 sulfur, 8,9 silicon, 10,11 and multielement. [12][13][14] In some regions or countries, despite their high flame retardant efficiency for PC, a majority of halogen-containing FRs for their adverse effects on environment and health have been strictly prohibited.…”