Mechanical and thermal properties of ABS/montmorillonite nanocomposites for fused deposition modeling 3D printing
Graphical abstract
Introduction
Three-dimensional (3D) printing is one of the most versatile and revolutionary additive manufacturing (AM) techniques to create 3D objects with unique structure and diverse properties [1]. Presently, various techniques such as fused deposition modeling (FDM) [2], stereolithography apparatus (SLA) [3], continuous liquid interface production (CLIP) [4], digital light processing (DLP) [5] and selective laser sintering (SLS) [6] have been developed to form stereoscopic objects with complex architecture. In the late 1980s, S. Scott Crump developed FDM 3D printer and it was commercialized by Stratasys in 1990 [7]. Now, FDM has become the most widely used 3D printing method due to its simple-to-use, low-cost and environment-friendly features and is increasingly used in product development, prototyping and manufacturing processes in a variety of industries, including household appliances, automobile, toys, architecture, medical appliances, aircraft and aerospace.
However, the followings limit the application of FDM 3D printing: the mechanical strength of the FDM printed products are usually worse compared with injection moulding due to their weakness points between the layers [8], and also, the thermoplastic materials tend to shrink during the cooling process, resulting in warp of the printed products [9]. To date, the FDM 3D printing has been studied in the fields of building equipments, materials [10], preparation techniques [11] and numerical simulation [12] and attracted more and more interests.
Usually, thermoplastic materials like ABS [13], [14], nylon [7], [15], polylactic acid (PLA) [16] and their blends [17] are used for FDM 3D printer. To enhance the mechanical properties of 3D printed thermoplastics, fiber-reinforced composites were used. However, addition of fibers often result in that the composites are susceptible to fracture during extrusion. Special additives may be necessary in the extrusion to help produce continuous and homogeneous filaments [18].
In recent years, the emergence of nanocomposites has attracted great interest amongst researchers. By using small volume fractions of nano-additives, mechanical properties [19], [20], heat distortion temperature [21], [22] and thermal stability [23], [24] of a polymer matrix can be improved. Thereinto, polymer/layered silicate (PLS) nanocomposites showed significant improvement in the properties of polymer matrix. Numerous studies reported the PLS nanocomposites exhibited better mechanical property, including dynamic mechanical [25], tensile [26], and flexural properties [21] than that of polymer matrix. Wang et al. [27] studied the thermal properties of ABS/montmorillonite nanocomposite. They observed that the intercalated-exfoliated structure was obtained and the thermal stability of ABS was improved by only 5 wt% of organ-montmorillonite. Lately, Yeh et al. [28] studied the tensile strength of ABS/organoclay nanocomposites, and found that the tensile strength can be improved 15% by adding 3 wt% of organoclay only.
Nowadays, various nanoreinforcements have been used in 3D printed materials, including nanocrystalline cellulose (NCC) [29], SiO2 [30], [31] and layered silicate [32], [33]. However, most of them were SLA 3D printed materials. FDM 3D printed nanocomposites have not been fully studied. In this work, FDM 3D printed nanocomposites were prepared. ABS nanocomposite samples were printed by a commercial FDM 3D printer. The mechanical properties of 3D printed nanocomposites samples were evaluated and compared to those of injection moulding samples. The thermal properties of ABS nanocomposites were also studied. It was found that the polymer nanocomposites could be promising high performance FDM 3D printed materials.
Section snippets
Materials
The pristine montmorillonite was purchased from Nanocor, trade name as PGW, its CEC is 145 ± 10%meq/100 g. Organic modifier, benzyldimethylhexadecylammonium chloride (HDBAC) was bought from Aladdin Industrial Inc., China. The chemical structure of HDBAC is shown in Fig. 1. ABS pellets, trade name as PA-705, was supplied by Qimei Stock Company, China.
Modification of pristine clay
According to Pinnavaia's [34], [35] method, 10 g of pristine clay was dispersed into 500 mL of distilled water at 60 °C and suspension was obtained.
Clay dispersion and morphology
Low angle X-ray diffraction (XRD) was used to determine the microstructure of the clay and its nanocomposites. The XRD patterns of pristine montmorillonite, OMMT and its nanocomposites are shown in Fig. 5. For pristine montmorillonite, a diffraction peak around 8.1° was observed, indicating a d-spacing of 1.27 nm. As for OMMT, an obvious diffraction peak at 4.4° was observed, corresponding to a d-spacing of 2.3 nm. This observation indicated that the pristine montmorillonite was modified by
Conclusions
A novel ABS/OMMT filaments used for FDM 3D printer were prepared by melt extrusion. First, pristine clay were organic modified by benzyldimethylhexadecylammonium chloride. The low angle XRD the TEM results showed that intercalated structure of ABS/OMMT structure were obtained. Second, different amount of OMMT were mixed with ABS pellets by a twin screw extruder and corresponding filament was prepared by single screw extruder. The tensile strength of ABS/OMMT nanocomposites prepared by FDM 3D
Acknowledgment
This research was financially supported by the National Natural Science Foundation of China (Grant No.: U1205114), the Natural Science Foundation of Fujian Province (Grant No.: 2014J01217 and 2015H0047), and the “Strategic Priority Research Program” of the Chinese Academy of Sciences (Grant No.: XDA09020301).
References (41)
- et al.
3D printing with polymers: challenges among expanding options and opportunities
Dent. Mater. Off. Publ. Acad. Dent. Mater.
(2016) - et al.
Development of new metal/polymer materials for rapid tooling using fused deposition modelling
Mater. Des.
(2004) - et al.
Mechanical behaviour of ABS: an experimental study using FDM and injection moulding techniques
J. Manuf. Process.
(2016) - et al.
Studies on thermal and mechanical properties of polyimide-clay nanocomposites
Polymer
(2001) - et al.
Development of controlled porosity polymer-ceramic composite scaffolds via fused deposition modeling
Mater. Sci. Eng. C Biomim. Supramol. Syst.
(2003) - et al.
Optimization of rapid prototyping parameters for production of flexible ABS object
J. Mater. Process. Technol.
(2005) - et al.
Synthesis and thermal behaviour of layered silicate-EVA nanocomposites
Polymer
(2001) - et al.
Poly(epsilon-caprolactone)/clay nanocomposites prepared by melt intercalation: mechanical, thermal and rheological properties
Polymer
(2002) - et al.
Polymer-layered silicate nanocomposites: preparation, properties and uses of a new class of materials
Mater. Sci. Eng. R. Rep.
(2000) - et al.
Preparation and thermal properties of ABS/montmorillonite nanocomposite
Polym. Degrad. Stab.
(2002)