Biography
Prof. Shu-Lin Bai
Prof. Shu-Lin Bai
School of Materials Science and Engineering, Peking University, Beijing, China
Title: FDM 3D printing of thermally conductive polymer nanocomposites
Abstract: 
Two-dimensional (2D) materials such as graphene and carbon nanotubes, exhibit distinguished electrical, thermal and mechanical properties. The polymers filled with such 2D materials are multifunctional with great potential to be applied in diverse fields. Due to extraordinary thermal conductivity (TC) of graphene, graphene filled polymer composites are thermally conductive and so can be used in heat management of electronic devices. However, the randomly dispersed graphene filled polymer composites meet the bottleneck of reinforcement of performance due to the agglomeration of graphene sheets. Therefore, many methods have been proposed to align high aspect-ratio graphene sheets like shear force, unidirectional/bidirectional freezing method, etc. Among them, shear force induced alignment is a facile and convenient way which exists in many extrusion processes. Specifically, extrusion-based three-dimensional (3D) printing following this principle is one of the emerging techniques to fabricate 3D entities with programmed microscopic and macroscopic structures. Generally, the fused deposition modelling (FDM) follows a simple and convenient fused deposition process through the extrusion of thermoplastic filaments. 
The combination of 3D printing and two-dimensional (2D) materials enables infinite possibilities for hierarchical aligned structure programming. In this work, we report the formation of asymmetrically aligned structure of graphene filled thermoplastic polyurethane (TPU) composites. The as-printed vertically aligned structure demonstrates a through-plane TC up to 12 W m-1 K-1 at 45 wt% graphene loading, which is ~8 times that of horizontally printed structure and surpasses many of the traditional particle reinforced polymer composites. The superior TC is mainly attributed to the anisotropic structure design benefited from the preferable degree of orientation of graphene and the multiscale dense structure realized by finely controlling the printing parameters. Finite element method (FEM) confirms the essential impact of anisotropic TC design for highly thermal conductive composites. 
Keywords: 3D printing, FDM, polymer nanocomposites, thermal properties
Biography: 
Professor Shu-Lin Bai obtained his PhD degree from Ecole Centrale de Arts et Manufactures de Paris, France in1993. He obtained his MS degree from Dept. of Engineering Mechanics in 1986 and BS degree in 1983 from Dept. of Materials Engineering of Dalian University of Technology, China. He joined Peking University from 1996. His expertise is in the area of polymer matrix composites filled with particles (graphene, CNTs, BN, SiO2, etc.) and fibers (carbon fiber, glass fiber, etc.), specially on processing and properties including thermal, electrical and mechanical properties. He has published about 130 journal papers and 40 conference papers. His current research focuses on design, manufacture and thermal/electrical/ mechanical properties of nanofillers filled polymer nanocomposite, as well as processing and application of long fiber reinforced thermoplastics (LFT). He is founder, chairman/co-chairman of Asia-Europe Symposium on Processing and Properties of Reinforced Polymers for many times.