Effects of carbon nanotubes on char structure and heat transfer in ethylene propylene diene monomer composites at high temperature

Effects of MWCNTs on Char Layer Structure and Physicochemical Reaction in Ethylene Propylene Diene Monomer Insulators

“…The differences in the morphological structure of the char layers are still attributed to the variations of MWCNTs and silica. For group NS, similar to the evolution trend of their char layer surface, the pores of the char layer cross-section gradually decrease with the increase in MWCNTs content, and the reason can also be attributed to the fixation of pyrolytic carbon by MWCNTs [ 27 , 28 , 29 , 31 , 32 , 33 ]. Silica can promote the deposition of pyrolysis carbon by melting to form a liquid film [ 8 , 18 ], resulting in the dense char layers of group S. However, due to the coverage of much pyrolysis carbon, the char layer cross-section of group S is difficult to observe their evolutionary way.…”

“…The loose structure can be easily invaded by the external heat flow, leading to the worst ablative resistance of NS-C-0. With the addition of MWCNTs, the high reactivity of MWCNTs promoted the deposition of pyrolysis gas [ 27 , 28 , 29 , 32 , 33 ], and some char residues appeared around the AF skeleton ( Figure 2 b,f) to improve the compactness of NS-C-0.3 char layer, and with the increase in MWCNTs, the accumulation of char residues based on AF skeleton is improved, making the char layer structure transform from looseness to porosity ( Figure 2 c,g), which enhances the ability to block heat flow and improves the ablative resistance. Furthermore, the char residues fixed by MWCNTs can prevent the carbon skeleton from contacting oxygen to protect it from oxidation [ 30 , 31 , 32 , 33 ], resulting in the improvement of oxidation resistance of the char layers.…”

“…), and thus, they were considered as highly effective ablative fillers. Especially MWCNTs with high strength and thermal conductivity are considered a promising ablative filler to improve the ablative resistance of EPDM-based insulators [ 25 , 26 , 27 , 28 , 29 ]. Li et al [ 25 , 26 ] found that the addition of MWCNTs in the EPDM-based insulators accelerates the carbothermal reduction reaction of silica to increase the char residue, resulting in the improvement of the ablative resistance.…”

“…Li et al [ 25 , 26 ] found that the addition of MWCNTs in the EPDM-based insulators accelerates the carbothermal reduction reaction of silica to increase the char residue, resulting in the improvement of the ablative resistance. In subsequent work, they [ 28 ] found that the char residues formed during the ablation can cover the surface of MWCNTs, which can effectively reduce the thermal conductivity of the char layers. In fact, the above ablation mechanisms were proposed based on the fact that the introduction of MWCNTs can affect the physicochemical reactions of silica during the ablation; however, the contribution of MWCNTs to char layer structure of EPDM-based insulators was unclear.…”

Effective recycling of end‐of‐life polyvinyl chloride foams in ethylene–propylene diene monomers rubber

“…[28] In one work, carbon nanotubes were also used to reduce the thermal conductivity and ablation rates of the char layer skeleton of EPDM composites at high temperature. [29,30] Interestingly, EPDM rubber composites with PVC as a filler have never been analyzed for its insulating properties. In fact, in the past, PVC has been used to improve the insulating properties of various materials like mortars and concrete.…”