Laser sintering of graphene nanoplatelets encapsulated polyamide powders
Binling Chen, Richard Davies, Yaan Liu, Nan Yi, Dayuan Qiang, Yanqiu Zhu, Oana Ghita
Abstract
This paper presents a comprehensive study in the fabrication and safety of new nanocomposite powders for laser sintering. The nanocomposite powder is based on a core-shell structure where nanoparticles (graphene nanoplatelets, GNP) are encapsulated on the surface of the polymeric particles (polyamides PA12) in a thin layer of poly(vinyl alcohol) (PVA). Powder rheology data as well as SEM and TEM showed that GNP were dispersed well in the PVA coating and improved flow. Half time crystallisation kinetics was used to determine differences induced in the polymer and the laser sintering process by the presence of GNP. Nanosafety aspects, critical in a manufacturing environment, are also considered here and exposure monitoring tests were carried out. Results confirmed a low nanoparticle air exposure and therefore confirmed the successful surface encapsulation of the GNP in nanocomposite powders. The laser-sintered 0.1GNP/PVA-PA12 parts showed enhanced mechanical properties in tensile, compression and 3-point bending test.