Biobased Foamed Thermoplastic Vulcanizate with Good Electromagnetic Interference and Self-Healing Performance

So far, functional polylactic acid-based thermoplastic vulcanizate (PLA-based TPV) has been less reported due to the low melt viscosity of PLA, which makes it difficult for the functional filler to be uniformly disperse in the TPV. In this work, we provide a novel stratagem to control the distribution of carbon nanotubes (CNT) in the PLA-based TPV and prepare a functional PLA-based TPV with good electromagnetic interference (EMI) and self-healing ability. We anchor the modified CNT in the PLA phase by grafting it on the PLA chains, to avoid the destruction of the conductive network by dynamic vulcanization. Simultaneously, the CNT selectively distributed in the PLA phase has little influence on the reconstruction of disulfide bonds in the epoxidized natural rubber (ENR) phase, resulting in a good self-healing ability of the TPV. When the content of CNT is 2 phr in PLA and the content of the curer is 3 phr in ENR, a PLA-based TPV with balanced electrical conductivity (1.54 × 10–4 S/m) and self-healing ability (67.5% after healing at 80 °C for 5 h) is prepared. Furthermore, the TPV can be foamed with the assistance of supercritical CO2, and the conductive path formed by CNT and the multi-interface result in a good EMI performance of the foamed TPV (up to 20 dB). The multifunctional biobased TPV shows great potential to be applied in the EMI field.