Volume exclusion effect and ambient temperature induced ultrahigh electromagnetic wave absorption properties of polylactic acid (PLA)/graphene nano-platelets (GNPs) composites

摘要

Conductive polymer composites (CPCs) have an excellent performance in dealing with electromagnetic (EM) radiation. The distribution of conductive fillers in CPCs plays a vital role in the electrical conductivity and EM wave-absorbing properties. Moreover, the distribution evolution of GNPs in the PLA matrix caused by the enhanced volume exclusion effect via annealing was investigated. Polylactic acid with 8 wt. graphene nano-platelets (PG8) achieved best performance among the composites. After 5-min heat treatment, the electrical conductivity and EM wave absorption properties of PLA/GNPs composites are significantly improved. With a simple treatment, the composite can reach an ultrahigh reflection loss (RL) value of -28.5 dB with a thickness of only 2.5 mm. By controlling the thickness in the range of 1-4 mm, the effective absorption bandwidth can be adjusted within 5.1-8.0 GHz. These methods provided in this work can effectively improve the EM wave absorption performance of CPCs and are worthy of being promoted.