Vermicular Ni@RL-CS: Preparation, characterization and its applications in electromagnetic shielding

Abstract

One-dimensional conductive materials are of great significance to the construction of conductive network in the polymer matrix due to their large aspect ratio. In this work, a nickel-plated rod-like calcium silicate composite (Ni@RL-CS) with unique vermicular structure was successfully fabricated by an electroless plating method. The structure and property of as-prepared Ni@RL-CS were characterized, and its electromagnetic shielding ability was evaluated through mixing with thermoplastic polyurethane (TPU). Results indicate that the Ni@RL-CS shows good electrical conductivity, magnetic property and strong dielectric loss ability. The Ni@RL-CS with a one-dimensional vermicular structure is easier to construct a continuous conductive network in TPU matrix, which greatly improves the electromagnetic shielding effectiveness of the TPU resin. TPU/Ni@RL-CS binary composite with 20 vol% Ni@RL-CS achieves ultrahigh specific EMI SE/thickness of 92.6 dB/mm in the frequency of X-band. By further hybridizing Ni@RL-CS with GNPs, the TPU/Ni@RL-CS/GNPs trinary composite exhibits excellent electromagnetic shielding performance. When the contents of Ni@RL-CS and GNPs are 10 vol% and 1.5 vol%, respectively, the specific EMI SE/thickness of the corresponding trinary composite reaches 74.6 dB/mm in the X-band owe to the dense conductive network, which is 56.5% higher than that of the binary TPU/Ni@RL-CS composite with the same content of 10 vol% Ni@RL-CS.. The synergistic effects of dielectric loss, magnetic loss, and the interfacial polarization loss are the main shielding mechanism. This work provides a strategy to prepare a functional filler based on an insulating inorganic material for electromagnetic shielding. The as-prepared Ni@RL-CS with the unique vermicular structure and outstanding electromagnetic shielding performance can serves as a functional filler to modify polymers for electromagnetic shielding applications.