Effect of Thermal Conductive Fillers on the Flame Retardancy, Thermal Conductivity, and Thermal Behavior of Flame-Retardant and Thermal Conductive Polyamide 6

Abstract

In this work, polyamide 6 (PA6) composites with improved flame retardancy and thermal conductivity were prepared with different thermal conductive fillers (TC fillers) such as aluminum nitride (AlN) and boron nitride (BN) in a PA6 matrix with aluminum diethylphosphinate (AlPi) as a fire retardant. The resultant halogen-free flame retardant (HFFR) and thermal conductive (TC) PA6 (HFFR-TC-PA6) were investigated in detail with a mechanical property test, a limiting oxygen index (LOI), the vertical burning test (UL-94), a cone calorimeter, a thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The morphology of the impact fracture surface and char residue of the composites were analyzed by scanning electron microscopy (SEM). It was found that the thermal conductivity of the HFFR-TC-PA6 composite increased with the amount of TC fillers. The TC fillers exerted a positive effect for flame retardant PA6. For example, the HFFR-TC-PA6 composites with the thickness of 1.6 mm successfully passed the UL-94 V-0 rating with an LOI of more than 29% when the loading amount of AlN-550RFS, BN-SW08 and BN-NW04 was 30 wt%. The morphological structures of the char residues revealed that TC fillers formed a highly integrated char layer surface (without holes) during the combustion process, as compared to that of flame retardant PA6/AlPi composites. In addition, the thermal stability and crystallization behavior of the composites were studied.

3D Thermal Network Supported by CF Felt for Improving the Thermal Performance of CF/C/Epoxy Composites

“…The method of adding fillers is a fast way to improve the thermal conductivity of polymers. Metal materials (such as copper powder [ 7 , 8 , 9 ], silver powder [ 10 , 11 ], metal sheet and wire [ 12 , 13 , 14 ]), carbon materials (such as carbon fiber (CF) [ 15 , 16 , 17 ], graphene material [ 18 , 19 ], graphite material [ 20 , 21 ], carbon nanotubes [ 22 , 23 ], carbon black [ 24 , 25 ]), inorganic fillers (such as aluminum nitride [ 26 , 27 ], boron nitride [ 28 , 29 , 30 ], silicon nitride [ 31 , 32 ], silicon carbide [ 33 ], alumina [ 34 , 35 ]) and other high thermal conductivity fillers are often used to improve the thermal conductivity of polymers. When the particulate filler content is small, it is difficult to significantly improve the thermal conductivity of the matrix.…”

Influence of in‐situ growth of boron nitride with chestnut ball copper cobaltate synergistic ammonium polyphosphate on flame retardancy, smoke suppression, and thermal conductivity of polylactic acid

“…Heat accumulation is a huge hidden danger of fire, and materials with a good heat dissipation effect will reduce heat accumulation to a certain extent. The quality of thermal conductivity directly affects the heat dissipation performance of materials, and thermal conductivity mainly refers to the phenomenon of heat transfer between substances 27,28 . Figure 11 presents the thermal conductivity chart of the PLA composite material, in which the thermal conductivity of pure PLA1 is relatively low, and the value is 0.20 W/(m K).…”

“…CC grows in situ on the surface of BN and forms a special sheet‐sphere structure. This special structure has the characteristics of one‐dimensional, two‐dimensional, and spherical thermal conductive filler, which can not only prevent the thermal conductive filler from agglomerating in the matrix, but also overlap each other in the composite material to form a thermal conduction path 28 …”

“…The quality of thermal conductivity directly affects the heat dissipation performance of materials, and thermal conductivity mainly refers to the phenomenon of heat transfer between substances. 27,28 Figure 11 presents the thermal conductivity chart of the PLA composite material, in which the thermal conductivity of pure PLA1 is relatively low, and the value is 0.20 W/(m K). Compared with PLA1, the thermal conductivity of PLA4 is increased by 28.0%, reaching 0.26 W/(m K).…”

Preparation and Characterization of Cyclodextrin Coated Red Phosphorus Double−Shell Microcapsules and Its Application in Flame Retardant Polyamide6

“…PA6 often works at high temperature, humidity, or voltage, in which it is easy to cause fire. Therefore, flame retardants have been used to improve the flame retardance of PA6 [ 3 , 4 , 5 ].…”