3D Printing Processability of a Thermally Conductive Compound Based on Carbon Nanofiller-Modified Thermoplastic Polyamide 12.

Zhenxue Zhang,Simon Jestin,Dionisis Semitekolos,Panagiotis-Nektarios Pappas,Xiaoying Li,Costas Charitidis,Anna Karatza,Eleni Gkartzou,Aikaterini-Flora Trompeta,Nikolaos Koutroumanis,Costas Galiotis,Panagiotis Zouboulis,Hanshan Dong

doi:10.3390/polym14030470

Abstract

A polyamide (PA) 12-based thermoplastic composite was modified with carbon nanotubes (CNTs), CNTs grafted onto chopped carbon fibers (CFs), and graphene nanoplatelets (GNPs) with CNTs to improve its thermal conductivity for application as a heat sink in electronic components. The carbon-based nanofillers were examined by SEM and Raman. The laser flash method was used to measure the thermal diffusivity in order to calculate the thermal conductivity. Electrical conductivity measurements were made using a Keithley 6517B electrometer in the 2-point mode. The composite structure was examined by SEM and micro-CT. PA12 with 15 wt% of GNPs and 1 wt% CNTs demonstrated the highest thermal conductivity, and its processability was investigated, utilizing sequential interdependence tests to evaluate the composite material behavior during fused filament fabrication (FFF) 3D printing processing. Through this assessment, selected printing parameters were investigated to determine the optimum parametric combination and processability window for the composite material, revealing that the selected composition meets the necessary criteria to be processable with FFF.

Highlights

Following the supported catalyst approach, the fibers (5–6 mm long) were impregnated in the catalyst solution (Fe particles embedded on zeolite, the same as the conventional procedure for carbon nanotubes (CNTs) synthesis in powder form) and left to dry
20 g of chopped carbon fibers (CFs) was introduced into the center of the metallic tube of the chemical vapor deposition (CVD) reactor
They were in an entangled form, withform, embedded catalyst at their end caps, implying a tip growth mechanism

Summary

Introduction

Conventional materials used for heat transfer applications, such as copper and aluminium, have the advantage of higher thermal conductivity but with higher cost and considerable weight. Low-cost thermoplastic composites with ease of manufacturability and recyclability are alternatives for such applications, with lower thermal conductivity in comparison to the metallic materials [1,2]. The conduction of thermal energy in a polymer is achieved via a phonon transfer process rather than through vibration in the pure crystalline materials. The vibrational frequency mismatches at the interfaces between impurities and lattice defects cause significant phonon “scattering”

Methods

Results

Conclusion