Polycarbonate/Sulfonamide Composites with Ultralow Contents of Halogen-Free Flame Retardant and Desirable Compatibility

Abstract

A novel halogen-free flame retardant containing sulfonamide, 1,3,5,7-tetrakis (phenyl-4-sulfonamide) adamantane (FRSN) was synthesized and used for improving the flame retardancy of largely used polycarbonate (PC). The flame-retardant properties of the composites with incorporation of varied amounts of FRSN were analyzed by techniques including limited oxygen index, UL 94 vertical burning, and cone calorimeter tests. The new FR system with sulfur and nitrogen elements showed effective improvements in PC’s flame retardancy: the LOI value of the modified PC increased significantly, smoke emission suppressed, and UL 94 V-0 achieved. Typically, the composite with only 0.08 wt% of FRSN added (an ultralow content) can increase the limiting oxygen index (LOI) value to 33.7% and classified as UL 94 V-0 rating. Furthermore, the mechanical properties and SEM morphology indicated that the FRSN has very good compatibility with PC matrix, which, in turn, is beneficial to the property enhancement. Finally, the analysis of sample residues after burning tests showed that a high portion of char was formed, contributing to the PC burning protection. This synthesized flame retardant provides a new way of improving PC’s flame retardancy and its mechanical property.

Sulfonate-Group-Containing Polymeric Polyamide for Simultaneous Transparency and Flame Retardancy of Polycarbonate

“…At 200 °C, less than 5 wt % weight loss appeared for SK, which should be resulting from the evaporation of crystalline water and absorbed moisture. The sharp weight loss between 400 and 480 °C is supposed to be the decomposition of amide groups . The last decomposition of SK occurred at 450–600 °C, in which a sulfonate group and SO 2 should be produced. , The release of acidic compound SO 2 may affect the thermal decomposition of PC and promote the charring of PC.…”

“…Numerous approaches have been used to adjust the fire safety of polymers, in which the most effective method is to incorporate flame retardant additives. , However, halogen-containing flame-retardant additives usually pose environmental hazards due to their high biotoxicity and potential accumulation in organisms. , Phosphorus flame-retardant additives are low-cost and have high efficiency, but traditional phosphate flame retardants exhibit a low initial decomposition temperature, , which may deteriorate some performances of PC. Sulfur-containing flame retardants, such as sodium trichlorobenzenesulfonate (STB) and potassium diphenylsulfone sulfonate (KSS), , have also been used in PC. Previously, Yu et al investigated the effect of sodium sulfonate grafted carbon black on the flame retardancy of PC.…”

A novel P‐S‐Si‐based cage‐structural monomer for flame‐retardant modification of unsaturated polyester resin

“…The results indicated that the introduction of TDCAA‐DOPO into UPR improved its thermal stability, promoted the formation of residual char, and increased LOI value 20 . Moreover, sulfur‐containing polymers have the characteristics of excellent thermal stability 21 . The introduction of phosphorus‐ and sulfur‐containing flame retardants into materials can bring about excellent flame retardancy possibly through cooperative interaction 22 .…”

A DOPO-Based Compound Containing Aminophenyl Silicone Oil for Reducing Fire Hazards of Polycarbonate

“…Chen et al [ 23 ] prepared PC-based composites blended with phosphazene-triazine bi-group flame retardant (A3); the PC/A3 composites reached a V-0 rating and 29.3% of LOI value in the case of 13.5% A3 loading level. Yang et al [ 24 ] synthesized a halogen-free FR containing sulfonamide (FRSN), the incorporation of only 0.08 wt% FRSN endowed PC with an LOI value of 33.7% and V-0 rating. According to the report of Hu et al [ 25 ], a novel P/Si-containing FR (P(DOPO-VTES)) was synthesized and adopted to improve the flame retardancy of PC.…”