Effects of Cellulose Nanocrystal and Inorganic Nanofillers on the Morphological and Mechanical Properties of Digital Light Processing (DLP) 3D-Printed Photopolymer Composites

Sang-U Bae,Birm-June Kim

doi:10.3390/app11156835

Abstract

Photopolymer composites filled with cellulose nanocrystal (CNC) and/or inorganic nanofillers were fabricated by using digital light processing (DLP) 3D printing. To investigate the effects of different CNC lyophilization concentrations and behaviors of CNC particles in the photopolymer composites, morphological and mechanical properties were analyzed. CNC loading levels affected the morphological and mechanical properties of the filled composites. Better CNC dispersion was seen at a lower lyophilization concentration, and the highest mechanical strength was observed in the 0.25 wt% CNC-filled composite. Furthermore, nano-precipitated calcium carbonate (nano-PCC) and nanoclay were added to photocurable resins, and then the effect of inorganic nanofillers on the morphological and mechanical properties of the composites were evaluated. By analyzing the morphological properties, the stress transfer mechanism of nano-PCC and nanoclay in the photopolymer composites was identified and related models were presented. These supported the improved mechanical strength of the composites filled with CNC, nano-PCC, and nanoclay. This study suggested a new approach using wood-derived cellulose nanomaterials and inorganic nanofillers as effective fillers for DLP 3D printing.

Highlights

The scanning electron microscope (SEM) images showed that the morphology of the cellulose nanocrystal (CNC) powder, which was obtained by lyophilization processes, was a large-sized agglomerate at low and high concentrations (Figures 3 and 4)
The SEM images showed that the morphology of the CNC powder, which was obThe SEM images showed that the morphology of the CNC powder, which was obtained by lyophilization processes, was a large-sized agglomerate at low and high6conof 19 tained by lyophilization processes, was a large-sized agglomerate at low and high concentrations (Figures 3 and 4)
Functional functionalnanoscale nanoscalematerials materials(CNCs, (CNCs,nano-PCC, nano-PCC,and andnanoclay) nanoclay)were wereadded added to liquid photocurable resins, and the resin blends were

Summary

Introduction

3D printing is attracting attention as a highly efficient technical alternative for manufacturing products that are difficult to produce with conventional manufacturing methods or that can only be produced through complex and numerous processes [4]. It has a lot of potentials in offering a wide range of geometrically complex structures, implementing large scale and high-precision models, and combining different technologies. The materials used for 3D printing still need to be developed and supplemented in terms of their range, usability and the physical properties of the end products [6]

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