Solid-state shear pan-milling preparation of graphene/TPU-HDPE nanocomposites with thermal conductivity and electromagnetic shielding

Abstract

Electromagnetic pollution and overheating present significant challenges in the development of microelectronic devices. Polyolefins, particularly high-density polyethylene (HDPE), are frequently used polymers in these devices. Therefore, enhancing the electromagnetic shielding efficiency (EMSE) and thermal conductivity of polyolefins is crucial for their performance in such applications. In this article, we synthesized a thermoplastic polyurethane (TPU) composed of 1,5-Naphthalene Diisocyanate (NDI), poly-caprolactone diol (PCL), and 1,4-butanediol (BDO) to regulate the viscoelasticity of high-density polyethylene (HDPE). The findings demonstrate that the graphenization of expanded graphite (EG) and the formation of nanocomposites with TPU-HDPE are achieved during the solid-state shear pan-milling process. This results in the uniform dispersion and high incorporation of 1–3 layers of graphene within the TPU-HDPE matrix. At an EG mass fraction of 50 %, the composite material achieves a thermal conductivity of 6.50 W/m·K, which is 16.25 times higher than that of HDPE. Its electrical conductivity reaches 113.1 S/cm. The EMSE measured as absorption loss (A) and total losses (T), increases as the electromagnetic frequency ranges from 8 GHz to 8.67 GHz. At 8.67 GHz, maximum A and T values of 59.04 dB/mm and 63.08 dB/mm, respectively, are observed.