Page 58 - MSAM-3-4

Materials Science in

Additive Manufacturing

ORIGINAL RESEARCH ARTICLE
Anti-microbial plastic parts fabricated by

high-speed sintering

Saleh Alkarri * , Zahir Bashir 2 , Marco Wimmer 3,4 , Johann Schorzmanm 3 ,
1
and Frank Döpper 3,4
1 School of Packaging, Michigan State University, East Lansing, Michigan, United States of America
2 Catenated Carbon Consultancy Ltd., Birmingham, England
3 Chair of Manufacturing and Remanufacturing Technologies, Faculty of Engineering, University of
Bayreuth, Bayreuth, Germany
4 Fraunhofer Institute for Manufacturing Engineering and Automation IPA, Bayreuth, Germany

Abstract

This study utilizes Mg(OH) nanocrystals (a non-leaching biocide) to develop plastic
2
articles with anti-microbial activity. The standard method for manufacturing plastic
nanocomposites involves melt compounding Mg(OH) nanocrystals into a polymer
2
melt, followed by injection molding; however, this approach did not produce a part
with anti-microbial activity because there were no Mg(OH) nanocrystals on the
2
surface of the parts. Anti-microbial polyamide 12 (PA 12) parts could be produced
using a specific 3D printing method called high-speed sintering (HSS). The HSS-
printed parts were subsequently dip-coated with an anti-microbial suspension of
*Corresponding author: Mg(OH) nanoplatelets (NPs). The Mg(OH) NPs embedded on the surface of the
2
2
Saleh Alkarri HSS-printed part exhibited a log 4 reduction (effective killing) of the bacterium
10
(Alkarris@msu.edu) Escherichia coli K-12 MG1655 (E. coli). The Mg(OH) NPs adhered well to the HSS-
2
Citation: Alkarri S, Bashir Z, printed parts and could be used repeatedly with no loss of anti-microbial activity.
Wimmer M, Schorzmanm J, In contrast, the dip-coated injection-molded PA 12 part was ineffective because
Döpper F. Anti-microbial plastic
parts fabricated by high-speed the Mg(OH) NPs did not adhere to it. The surface of the HSS-printed part naturally
2
sintering. Mater Sci Add Manuf. allows the binding of the Mg(OH) nanocrystals. The anti-microbial activity of
2
2024;3(4):4970. Mg(OH) NPs depends on direct contact between them and the microbe, which is
doi: 10.36922/msam.4970 2
feasible with the dip-coated HSS-printed part but not with the injection-molded
Received: September 27, 2024 nanocomposite. The work illustrates some of the unique possibilities arising from
Revised: October 18, 2024 3D printing.
Accepted: October 23, 2024
Published Online: December 3, Keywords: Anti-microbial plastics; E. coli K-12 MG1655; Magnesium hydroxide;
2024 Non-leachable; Polyamide 12; High-speed sintering; Additive manufacturing
Copyright: © 2024 Author(s).
This is an Open-Access article
distributed under the terms of the
Creative Commons Attribution
License, permitting distribution, 1. Introduction
and reproduction in any medium,
provided the original work is Many microbes cause infections, with highly infectious diseases typically spreading
properly cited. through respiratory means and physical contact. Bacterial infections may be curable
Publisher’s Note: AccScience post-infection by antibiotics, but the rise of drug-resistant bacteria has posed a significant
Publishing remains neutral with challenge. One way to reduce the spread of infections is to reduce the accumulation
regard to jurisdictional claims in
published maps and institutional of disease-causing microbes on surfaces that are handled in hospitals and public
affiliations. spaces. Polymeric materials play a crucial role in healthcare as components of medical

Volume 3 Issue 4 (2024) 1 doi: 10.36922/msam.4970