scholarly journals Piezoresistive Behaviour of Additively Manufactured Multi-Walled Carbon Nanotube/Thermoplastic Polyurethane Nanocomposites

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2613 ◽  
Author(s):  
Myoungsuk Kim ◽  
Jaebong Jung ◽  
Sungmook Jung ◽  
Young Hoon Moon ◽  
Dae-Hyeong Kim ◽  
...  
Keyword(s):  
Large Scale ◽  
Thermoplastic Polyurethane ◽  
Pressure Sensors ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Fused Deposition Modelling ◽  
Fused Deposition ◽  
Multi Walled Carbon Nanotubes ◽  
Flexible Pressure Sensors ◽  
Walled Carbon Nanotubes

To develop highly sensitive flexible pressure sensors, the mechanical and piezoresistive properties of conductive thermoplastic materials produced via additive manufacturing technology were investigated. Multi-walled carbon nanotubes (MWCNTs) dispersed in thermoplastic polyurethane (TPU), which is flexible and pliable, were used to form filaments. Specimens of the MWCNT/TPU composite with various MWCNT concentrations were printed using fused deposition modelling. Uniaxial tensile tests were conducted, while the mechanical and piezoresistive properties of the MWCNT/TPU composites were measured. To predict the piezoresistive behaviour of the composites, a microscale 3D resistance network model was developed. In addition, a continuum piezoresistive model was proposed for large-scale simulations.

scholarly journals Microstructure Evaluation and Thermal–Mechanical Properties of ABS Matrix Composite Filament Reinforced with Multi-Walled Carbon Nanotubes by a Single Screw Extruder for FDM 3D Printing

2021 ◽  
Vol 11 (19) ◽  
pp. 8798
Author(s):  
Thai-Hung Le ◽  
Van-Son Le ◽  
Quoc-Khanh Dang ◽  
Minh-Thuyet Nguyen ◽  
Trung-Kien Le ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Fused Deposition Modeling ◽  
Acrylonitrile Butadiene Styrene ◽  
Melt Flow Index ◽  
Tensile Tests ◽  
Flow Index ◽  
Fused Deposition ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Composite Filament

This paper reports the synthesis of a new printable ABS–MWCNT composite filament, for use in fused deposition modeling (FDM), using an extrusion technique. Acrylonitrile butadiene styrene (ABS) and multi-walled carbon nanotubes (MWCNTs) were the initial materials used for fabricating the filaments. The MWCNTs were dispersed in ABS resin, then extruded through a single-shaft extruder in filament form, with MWCNT contents of 0.5%, 1%, 1.5%, 2%, 3% or 4% by weight. After extrusion, the diameter of the filaments was about 1.75 mm, making them appropriate for FDM. The as-synthesized filaments were then used in FDM to print out samples, on which tensile tests and other analyses were carried out. The results demonstrate that the sample with 2% MWCNTs had the highest strength value, 44.57 MPa, comprising a 42% increase over that of the pure ABS sample. The morphology and dispersion of MWCNTs in the composite were observed by field emission scanning electron microscopy (FESEM), demonstrating the uniform distribution of MWCNTs in the ABS matrix. The thermal behavior results indicated no significant change in the ABS structure; however, the melt flow index of the filaments decreased with an increase in the MWCNT content.

Characterization of PLA/TPU composite filaments manufactured for 3D printing with FDM

2021 ◽  
pp. 089270572110625
Author(s):  
Ajay Jayswal ◽  
Sabit Adanur
Keyword(s):  
3D Printing ◽  
Fused Deposition Modeling ◽  
Thermoplastic Polyurethane ◽  
Tensile Tests ◽  
Optical Microscope ◽  
Mechanical Analysis ◽  
Uniaxial Tensile ◽  
Scanning Calorimetry ◽  
Fused Deposition ◽  
3D Printed

Polylactic acid (PLA) and thermoplastic polyurethane (TPU) were mixed in different proportions and extruded through twin-screw and single-screw extruders to obtain composite filaments to be used for 3D printing with fused deposition modeling (FDM) method. The properties of the filaments were characterized using uniaxial tensile tests, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), rheology, polarized optical microscope (POM), and scanning electron microscope (SEM). 3D printed samples from composite filaments were tested using dynamic mechanical analysis (DMA). It was found that the tensile strength and modulus of the filaments decrease while elongation at break increases with the increasing TPU content in the composite. The analysis also showed a partial miscibility of the polymer constituents in the solution of composite filaments. Finally, a flexible structure, plain weave fabric, was designed and 3D printed using the composite filaments developed which proved that the filaments are well suited for 3D printing.

scholarly journals Electrical and Thermal Conductivity of Polylactic Acid (PLA)-Based Biocomposites by Incorporation of Nano-Graphite Fabricated with Fused Deposition Modeling

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 549 ◽  
Author(s):  
Rui Guo ◽  
Zechun Ren ◽  
Hongjie Bi ◽  
Min Xu ◽  
Liping Cai
Keyword(s):  
Thermal Conductivity ◽  
Polylactic Acid ◽  
Fused Deposition Modeling ◽  
Wood Flour ◽  
Thermoplastic Polyurethane ◽  
Volume Resistivity ◽  
Fused Deposition ◽  
Multi Walled Carbon Nanotubes ◽  
Deposition Modeling ◽  
Walled Carbon Nanotubes

The aim of the study was to improve the electrical and thermal conductivity of the polylactic acid/wood flour/thermoplastic polyurethane composites by Fused Deposition Modeling (FDM). The results showed that, when the addition amount of nano-graphite reached 25 pbw, the volume resistivity of the composites decreased to 108 Ω·m, which was a significant reduction, indicating that the conductive network was already formed. It also had good thermal conductivity, mechanical properties, and thermal stability. The adding of the redox graphene (rGO) combined with graphite into the composites, compared to the tannic acid-functionalized graphite or the multi-walled carbon nanotubes, can be an effective method to improve the performance of the biocomposites, because the resistivity reduced by one order magnitude and the thermal conductivity increased by 25.71%. Models printed by FDM illustrated that the composite filaments have a certain flexibility and can be printed onto paper or flexible baseplates.

scholarly journals Low-Cost and Highly Sensitive Pressure Sensor with Mold-Printed Multi-Walled Carbon Nanotubes Dispersed in Polydimethylsiloxane

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5069
Author(s):  
Tim Mike de Rijk ◽  
Walter Lang
Keyword(s):  
Carbon Nanotubes ◽  
Pressure Sensor ◽  
Low Cost ◽  
Conductive Polymer ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Multi Walled Carbon Nanotubes ◽  
Pressure Changes ◽  
Flexible Pressure Sensors ◽  
Walled Carbon Nanotubes

Flexible pressure sensors with piezoresistive polymer composites can be integrated into elastomers to measure pressure changes in sealings, preemptively indicating a replacement is needed before any damage or leakage occurs. Integrating small percentages of high aspect ratio multi-walled carbon nanotubes (MWCNTs) into polymers does not significantly change its mechanical properties but highly affects its electrical properties. This research shows a pressure sensor based on homogeneous dispersed MWCNTs in polydimethylsiloxane with a high sensitivity region (0.13% kPa−1, 0–200 kPa) and sensitive up to 500 kPa. A new 3D-printed mold is developed to directly deposit the conductive polymer on the electrode structures, enabling sensor thicknesses as small as 100 μm.

scholarly journals Influence of fabrication parameters on the elastic modulus and characteristic stresses in 3D printed PLA samples produced via fused deposition modelling technique

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sebastián Tognana ◽  
Susana Montecinos ◽  
Rosana Gastien ◽  
Walter Salgueiro
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Tensile Tests ◽  
Maximum Tensile Stress ◽  
Specific Yield ◽  
Uniaxial Tensile ◽  
Fused Deposition Modelling ◽  
Fused Deposition ◽  
Modes Of Vibration ◽  
3D Printed

Abstract Commonly used 3D printed samples are partially infilled to reduce time and cost of printing, with mechanical properties dependent on the infill. In this work, the influence of the percentage and pattern of infill in PLA printed samples on the elastic modulus and characteristic stresses was analyzed. The elastic modulus, E, and characteristic stresses (σ 0.2, σ 4 and the maximum tensile stress) were determined for each sample using impulse excitation technique, IET, and uniaxial tensile tests. An apparent density was calculated for each pattern and infill percentage, and the mechanical parameters were studied as a function of such density. The results of IET obtained in different modes of vibration were analyzed and an apparent value of E was calculated. FEM simulations were carried out and the results were compared with the experimental ones. The mechanical properties for different infill percentages and infill patterns were studied by comparing the specific values of E and the stresses. Samples with higher infill percentages exhibit the best specific values of maximum stress and E, but the sample with 20% infill has the highest specific yield stress and a good value of the specific E from flexural vibrations.

scholarly journals Polymeric Composites Based on Polyurea Matrix Reinforced with Carbon Nanotubes

2017 ◽  
Vol 54 (1) ◽  
pp. 41-44 ◽  
Author(s):  
Maria Adina Vulcan ◽  
Celina Damian ◽  
Paul Octavian Stanescu ◽  
Eugeniu Vasile ◽  
Razvan Petre ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Thermal Stability ◽  
Scanning Electron Microscopy ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

This paper deals with the synthesis of polyurea and its use as polymer matrix for nanocomposites reinforced with multi-walled carbon nanotubes (MWCNT). Two types of materials were obtained during this research, the first cathegory uses the polyurea as matrix and the second one uses a mixture between epoxy resin and polyurea. The nanocomposites were characterized by Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM) and Tensile Tests .The elastomeric features of nanocomposites were highlighted by the results which showed low value of Tg. Also higher thermal stability with ~40oC compared with commercial products (M20) were observed, but lower mechanical properties compared to neat polyurea.

Tensile properties of the FFF-processed thermoplastic polyurethane (TPU) elastomer

2021 ◽  
Author(s):  
Budi Arifvianto ◽  
Teguh Nur Iman ◽  
Benidiktus Tulung Prayoga ◽  
Rini Dharmastiti ◽  
Urip Agus Salim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Low Cost ◽  
Thermoplastic Polyurethane ◽  
High Strength ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Fused Filament Fabrication ◽  
Raster Angle ◽  
Manufacturing Techniques

Abstract Fused filament fabrication (FFF) has become one of the most popular, practical, and low-cost additive manufacturing techniques for fabricating geometrically-complex thermoplastic polyurethane (TPU) elastomer. However, there are still some uncertainties concerning the relationship between several operating parameters applied in this technique and the mechanical properties of the processed material. In this research, the influences of extruder temperature and raster orientation on the mechanical properties of the FFF-processed TPU elastomer were studied. A series of uniaxial tensile tests was carried out to determine tensile strength, strain, and elastic modulus of TPU elastomer that had been printed with various extruder temperatures, i.e., 190–230 °C, and raster angles, i.e., 0–90°. Thermal and chemical characterizations were also conducted to support the analysis in this research. The results obviously showed the ductile and elastic characteristics of the FFF-processed TPU, with specific tensile strength and strain that could reach up to 39 MPa and 600%, respectively. The failure mechanisms operating on the FFF-processed TPU and the result of stress analysis by using the developed Mohr’s circle are also discussed in this paper. In conclusion, the extrusion temperature of 200 °C and raster angle of 0° could be preferred to be applied in the FFF process to achieve high strength and ductile TPU elastomer.

Use of polymer concrete for large-scale 3D printing

2021 ◽  
Vol 27 (3) ◽  
pp. 465-474
Author(s):  
Martin Krčma ◽  
David Škaroupka ◽  
Petr Vosynek ◽  
Tomáš Zikmund ◽  
Jozef Kaiser ◽  
...  
Keyword(s):  
3D Printing ◽  
Large Scale ◽  
Mechanical Performance ◽  
Construction Material ◽  
Polymer Concrete ◽  
Fused Deposition Modelling ◽  
Cast State ◽  
Content Type ◽  
Fused Deposition ◽  
3D Printed

Purpose This paper aims to focus on the evaluation of a polymer concrete as a three-dimensional (3D) printing material. An associated company has developed plastic concrete made from reused unrecyclable plastic waste. Its intended use is as a construction material. Design/methodology/approach The concrete mix, called PolyBet, composed of polypropylene and glass sand, is printed by the fused deposition modelling process. The process of material and parameter selection is described. The mechanical properties of the filled material were compared to its cast state. Samples were made from castings and two different orientations of 3D-printed parts. Three-point flex tests were carried out, and the area of the break was examined. Computed tomography of the samples was carried out. Findings The influence of the 3D printing process on the material was evaluated. The mechanical performance of the longitudinal samples was close to the cast state. There was a difference in the failure mode between the states, with cast parts exhibiting a tougher behaviour, with fractures propagating in a stair-like manner. The 3D-printed samples exhibited high degrees of porosity. Originality/value The results suggest that the novel material is a good fit for 3D printing, with little to no degradation caused by the process. Layer adhesion was shown to be excellent, with negligible effect on the finished part for the longitudinal orientation. That means, if large-scale testing of buildability is successful, the material is a good fit for additive manufacturing of building components and other large-scale structures.

scholarly journals 3D Printing of Drug-Loaded Thermoplastic Polyurethane Meshes: A Potential Material for Soft Tissue Reinforcement in Vaginal Surgery

Pharmaceutics ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 63 ◽  
Author(s):  
Juan Domínguez-Robles ◽  
Caterina Mancinelli ◽  
Elena Mancuso ◽  
Inmaculada García-Romero ◽  
Brendan F. Gilmore ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermoplastic Polyurethane ◽  
Vaginal Surgery ◽  
Pelvic Organ ◽  
Attenuated Total Reflection ◽  
Fused Deposition Modelling ◽  
Suitable Material ◽  
3D Print ◽  
Fused Deposition ◽  
Poly Propylene

Current strategies to treat pelvic organ prolapse (POP) or stress urinary incontinence (SUI), include the surgical implantation of vaginal meshes. Recently, there have been multiple reports of issues generated by these meshes conventionally made of poly(propylene). This material is not the ideal candidate, due to its mechanical properties leading to complications such as chronic pain and infection. In the present manuscript, we propose the use of an alternative material, thermoplastic polyurethane (TPU), loaded with an antibiotic in combination with fused deposition modelling (FDM) to prepare safer vaginal meshes. For this purpose, TPU filaments containing levofloxacin (LFX) in various concentrations (e.g., 0.25%, 0.5%, and 1%) were produced by extrusion. These filaments were used to 3D print vaginal meshes. The printed meshes were fully characterized through different tests/analyses such as fracture force studies, attenuated total reflection-Fourier transform infrared, thermal analysis, scanning electron microscopy, X-ray microcomputed tomography (μCT), release studies and microbiology testing. The results showed that LFX was uniformly distributed within the TPU matrix, regardless the concentration loaded. The mechanical properties showed that poly(propylene) (PP) is a tougher material with a lower elasticity than TPU, which seemed to be a more suitable material due to its elasticity. In addition, the printed meshes showed a significant bacteriostatic activity on both Staphylococcus aureus and Escherichia coli cultures, minimising the risk of infection after implanting them. Therefore, the incorporation of LFX to the TPU matrix can be used to prepare anti-infective vaginal meshes with enhanced mechanical properties compared with current PP vaginal meshes.

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