Effect of intercalated anions on the performance of Ni–Al LDH nanofiller of ethylene vinyl acetate composites

The dodecylsulfate (DDS) intercalated and surface uptaken nano-LDHs containing Ni were rapidly synthesized based on the coprecipitation coupled with the microwave hydrothermal treatment. The nature of the interlayer anions, the morphology, the thermal stability, the hydrophilicity and the hydrophobicity of the preparing all LDHs were investigated by IR, XRD, TEM, SEM, TGA–DTG and contact angle measurement. As a flame retardant nanofiller, DDS-intercalated LDH NiAl-DDS and EVA matrix had the best compatibility in comparison with both the carbonate intercalated LDH NiAl–CO3 and DDS surface uptaken LDH DDS-NiAl–CO3. The composite NiAl-DDS/EVA showed not only a significant decrease in the heat release rate (HRR), the smoke production rate (SPR), the average mass loss rate (AMLR) and the production of CO (COP), but also the best thermal stability and ductility in comparison with both the pristine EVA and other composites. In addition, when the addition of 20 wt.% of LDHs was chosen as the maximum content point of comparison, the tensile strength value of DDS-NiAl–CO3 was 19.8 MPa, while that of NiAl-CO3 decreased to 14.8 MPa. DDS-NiAl–CO3 was the best reinforcing filler in EVA.

Graphical abstractThe contact angles of DDS-NiAl–CO3 and NiAl-DDS are larger than that of the SDS (41°) and the unmodified LDH NiAl–CO3 (46°). Furthermore, the contact angle value of NiAl-DDS is larger than that of the EVA (85°). Therefore, the composite NiAl-DDS/EVA shows the best thermal stability, the flame retardance and the ductility.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► DDS-modified nano-LDHs were synthesized by using the microwave treatment. ► NiAl-DDS/EVA shows the highest thermal stability and ductility among the composites. ► NiAl-DDS/EVA shows the best flame retardance among the composites.