scholarly journals Dielectric Spectroscopy and Thermal Properties of Poly(lactic) Acid Reinforced with Carbon-Based Particles: Experimental Study and Design Theory

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2414
Author(s):  
Giovanni Spinelli ◽  
Rumiana Kotsilkova ◽  
Evgeni Ivanov ◽  
Vladimir Georgiev ◽  
Radost Ivanova ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Dielectric Spectroscopy ◽  
Design Theory ◽  
Fused Deposition Modeling ◽  
Interfacial Polarization ◽  
Poly Lactic Acid ◽  
Neat Polymer ◽  
Carbonaceous Particles ◽  
Fused Deposition ◽  
3D Printed

In the present study, polylactic acid (PLA) enriched with carbonaceous particles like multi-walled carbon nanotubes (MWCNTs), graphene nanoplates (GNPs) or a combination of both up 12 wt % of loading are used for producing 3D-printed specimens with fused deposition modeling (FDM) technology which are then experimentally and theoretically investigated. The goal is to propose a non-conventional filaments indicated for additive manufacturing process with improved dielectric and thermal properties, compared to the performances exhibited by the unfilled polymer. In the light of the above, a wide dielectric spectroscopy and a thermal analysis, supported by a morphological investigation, are performed. The results highlight that the introduction of 1-dimensional filler (MWCNTs) are more suitable for improving the dielectric properties of the resulting materials, due to the enhancement of the interfacial polarization and the presence of functionalized groups, whereas 2-dimensional nanoparticles (GNPs) better favor the thermal conduction mechanisms thanks to the lower thermal boundary resistance between the two phases, polymer/filler. In particular, with a loading of 12 wt % of MWCNTs the relative permittivity reaches the value of 5.35 × 103 much greater than that of 3.7 measured for unfilled PLA while for the thermal conductivity the enhancement with 12 wt % of GNPs is about 261% respect the thermal behavior of the neat polymer. The experimental results are correlated to theoretical findings, whereas a design of experiment (DoE) approach is adopted for investigating how the different fillers influence the dielectric and thermal performances of the 3D-printed parts, thus assisting the design of such innovative materials that appear promising for development and applications in the electromagnetic (EM) field and heat transfer.

scholarly journals Pressure Orientation-Dependent Recovery of 3D-Printed PLA Objects with Varying Infill Degree

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1275 ◽  
Author(s):  
Guido Ehrmann ◽  
Andrea Ehrmann
Keyword(s):  
Shape Memory ◽  
Fused Deposition Modeling ◽  
Static Load ◽  
Shape Memory Polymer ◽  
Applied Pressure ◽  
Poly Lactic Acid ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
Load Tests ◽  
3D Printed

Poly(lactic acid) is not only one of the most often used materials for 3D printing via fused deposition modeling (FDM), but also a shape-memory polymer. This means that objects printed from PLA can, to a certain extent, be deformed and regenerate their original shape automatically when they are heated to a moderate temperature of about 60–100 °C. It is important to note that pure PLA cannot restore broken bonds, so that it is necessary to find structures which can take up large forces by deformation without full breaks. Here we report on the continuation of previous tests on 3D-printed cubes with different infill patterns and degrees, now investigating the influence of the orientation of the applied pressure on the recovery properties. We find that for the applied gyroid pattern, indentation on the front parallel to the layers gives the worst recovery due to nearly full layer separation, while indentation on the front perpendicular to the layers or diagonal gives significantly better results. Pressing from the top, either diagonal or parallel to an edge, interestingly leads to a different residual strain than pressing from front, with indentation on top always firstly leading to an expansion towards the indenter after the first few quasi-static load tests. To quantitatively evaluate these results, new measures are suggested which could be adopted by other groups working on shape-memory polymers.

Development of three-dimensional printing filaments based on poly(lactic acid)/hydroxyapatite composites with potential for tissue engineering

2021 ◽  
pp. 002199832098856
Author(s):  
Marcela Piassi Bernardo ◽  
Bruna Cristina Rodrigues da Silva ◽  
Luiz Henrique Capparelli Mattoso
Keyword(s):  
Tissue Engineering ◽  
Lactic Acid ◽  
Fused Deposition Modeling ◽  
Three Dimensional ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Three Dimensional Printing ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
3D Printed

Injured bone tissues can be healed with scaffolds, which could be manufactured using the fused deposition modeling (FDM) strategy. Poly(lactic acid) (PLA) is one of the most biocompatible polymers suitable for FDM, while hydroxyapatite (HA) could improve the bioactivity of scaffold due to its chemical composition. Therefore, the combination of PLA/HA can create composite filaments adequate for FDM and with high osteoconductive and osteointegration potentials. In this work, we proposed a different approache to improve the potential bioactivity of 3D printed scaffolds for bone tissue engineering by increasing the HA loading (20-30%) in the PLA composite filaments. Two routes were investigated regarding the use of solvents in the filament production. To assess the suitability of the FDM-3D printing process, and the influence of the HA content on the polymer matrix, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were performed. The HA phase content of the composite filaments agreed with the initial composite proportions. The wettability of the 3D printed scaffolds was also increased. It was shown a greener route for obtaining composite filaments that generate scaffolds with properties similar to those obtained by the solvent casting, with high HA content and great potential to be used as a bone graft.

scholarly journals Effects of Rice Straw Powder (RSP) Size and Pretreatment on Properties of FDM 3D-Printed RSP/Poly(Lactic Acid) Biocomposites

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3234
Author(s):  
Wangwang Yu ◽  
Lili Dong ◽  
Wen Lei ◽  
Yuhan Zhou ◽  
Yongzhe Pu ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Rice Straw ◽  
Fused Deposition Modeling ◽  
Flexural Modulus ◽  
Tensile Modulus ◽  
Cost Effective ◽  
Poly Lactic Acid ◽  
Fused Deposition ◽  
Interfacial Compatibility ◽  
3D Printed

To develop a new kind of environment-friendly composite filament for fused deposition modeling (FDM) 3D printing, rice straw powder (RSP)/poly(lactic acid) (PLA) biocomposites were FDM-3D-printed, and the effects of the particle size and pretreatment of RSP on the properties of RSP/PLA biocomposites were investigated. The results indicated that the 120-mesh RSP/PLA biocomposites (named 120#RSP/PLA) showed better performance than RSP/PLA biocomposites prepared with other RSP sizes. Infrared results showed that pretreatment of RSP by different methods was successful, and scanning electron microscopy indicated that composites prepared after pretreatment exhibited good interfacial compatibility due to a preferable binding force between fiber and matrix. When RSP was synergistically pretreated by alkaline and ultrasound, the composite exhibited a high tensile strength, tensile modulus, flexural strength, and flexural modulus of 58.59, 568.68, 90.32, and 3218.12 MPa, respectively, reflecting an increase of 31.19%, 16.48%, 18.75%, and 25.27%, respectively, compared with unmodified 120#RSP/PLA. Pretreatment of RSP also improved the thermal stability and hydrophobic properties, while reducing the water absorption of 120#RSP/PLA. This work is believed to provide highlights of the development of cost-effective biocomposite filaments and improvement of the properties of FDM parts.

scholarly journals Effects of wood flour and MA-EPDM on the properties of fused deposition modeling 3D-printed poly lactic acid composites

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 7122-7138
Author(s):  
Sang-U Bae ◽  
Young-Rok Seo ◽  
Birm-June Kim ◽  
Min Lee
Keyword(s):  
Lactic Acid ◽  
3D Printing ◽  
Fused Deposition Modeling ◽  
Wood Flour ◽  
Poly Lactic Acid ◽  
Common System ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
3D Printed ◽  
Material Composite

Fused deposition modeling (FDM) 3D printing technology is the most common system for polymer additive manufacturing (AM). Recent studies have been conducted to expand both the range of materials that can be used for FDM and their applications. As a filler, wood flour was incorporated into poly lactic acid (PLA) polymer to develop a biocomposite material. Composite filaments were manufactured with various wood flour contents and then successfully used for 3D printing. Morphological, mechanical, and biodegradation properties of FDM 3D-printed PLA composites were investigated. To mitigate brittleness, 5 phr of maleic anhydride grafted ethylene propylene diene monomer (MA-EPDM) was added to the composite blends, and microstructural properties of the composites were examined by scanning electron microscopy (SEM). Mechanical strength tests demonstrated that elasticity was imparted to the composites. Additionally, test results showed that the addition of wood flour to the PLA matrix promoted pore generation and further influenced the mechanical and biodegradation properties of the 3D-printed composites. An excellent effect of wood flour on the biodegradation properties of FDM 3D-printed PLA composites was observed.

scholarly journals Fabrication of 3D-Printed Biodegradable Porous Scaffolds Combining Multi-Material Fused Deposition Modeling and Supercritical CO2 Techniques

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1080 ◽  
Author(s):  
Raúl Sanz-Horta ◽  
Carlos Elvira ◽  
Alberto Gallardo ◽  
Helmut Reinecke ◽  
Juan Rodríguez-Hernández
Keyword(s):  
Additive Manufacturing ◽  
Supercritical Co2 ◽  
Fused Deposition Modeling ◽  
Poly Lactic Acid ◽  
Porous Scaffolds ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
3D Printed ◽  
Internal Pore ◽  
A Current

The fabrication of porous materials for tissue engineering applications in a straightforward manner is still a current challenge. Herein, by combining the advantages of two conventional methodologies with additive manufacturing, well-defined objects with internal and external porosity were produced. First of all, multi-material fused deposition modeling (FDM) allowed us to prepare structures combining poly (ε-caprolactone) (PCL) and poly (lactic acid) (PLA), thus enabling to finely tune the final mechanical properties of the printed part with modulus and strain at break varying from values observed for pure PCL (modulus 200 MPa, strain at break 1700%) and PLA (modulus 1.2 GPa and strain at break 5–7%). More interestingly, supercritical CO2 (SCCO2) as well as the breath figures mechanism (BFs) were additionally employed to produce internal (pore diameters 80–300 µm) and external pores (with sizes ranging between 2 and 12 μm) exclusively in those areas where PCL is present. This strategy will offer unique possibilities to fabricate intricate structures combining the advantages of additive manufacturing (AM) in terms of flexibility and versatility and those provided by the SCCO2 and BFs to finely tune the formation of porous structures.

Silane-Treated Muscovite as Reinforcement for 3D-Printed ABS via Fused Deposition Modeling

2021 ◽  
Vol 877 ◽  
pp. 67-72
Author(s):  
Niño B. Felices ◽  
Bryan B. Pajarito
Keyword(s):  
Thermal Properties ◽  
Fused Deposition Modeling ◽  
Acrylonitrile Butadiene Styrene ◽  
Mechanical And Thermal Properties ◽  
Scanning Calorimetry ◽  
Mechanical Reinforcement ◽  
Fused Deposition ◽  
The Matrix ◽  
Deposition Modeling ◽  
3D Printed

Epoxysilane-treated muscovite (ETM) was used as reinforcing filler to 3D-printed acrylonitrile butadiene styrene (ABS) via fused deposition modeling (FDM). Its effects to the mechanical and thermal properties of ABS were investigated. ETM was loaded at 1, 3, and 5wt%. ABS/ETM composites were characterized via scanning electron microscopy (SEM), tensile test, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Mechanical reinforcement of ABS was observed for ABS/ETM composites loaded at 1 and 3 wt% wherein it was noted that the tensile strength and elastic modulus increased by up to 83.6% and 76.6%, respectively. Reinforcement was brought by interfacial adhesion of ETM with the ABS matrix. There was a sharp decline in mechanical properties for ABS/ETM composites loaded at 5wt% due to agglomeration of ETM in the matrix and discontinuities in the printed layers. The glass transition temperature (Tg) of ABS increased and the onset of its degradation shifted towards higher temperatures with the addition of ETM. It can be concluded that the addition of ETM to ABS for FDM 3D printing improved its mechanical and thermal properties.

scholarly journals Mechanical Properties of FDM Printed PLA Parts before and after Thermal Treatment

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1239
Author(s):  
Ali Chalgham ◽  
Andrea Ehrmann ◽  
Inge Wickenkamp
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Process Parameters ◽  
Fused Deposition Modeling ◽  
Poly Lactic Acid ◽  
Three Point Bending ◽  
Fused Deposition ◽  
Before And After ◽  
Deposition Modeling ◽  
3D Printed

Fused deposition modeling (FDM) is one of the most often-used technologies in additive manufacturing. Several materials are used with this technology, such as poly(lactic acid) (PLA), which is most commonly applied. The mechanical properties of 3D-printed parts depend on the process parameters. This is why, in this study, three-point bending tests were carried out to characterize the influence of build orientation, layer thickness, printing temperature and printing speed on the mechanical properties of PLA samples. Not only the process parameters may affect the mechanical properties, but heat after-treatment also has an influence on them. For this reason, additional samples were printed with optimal process parameters and characterized after pure heat treatment as well as after deformation at a temperature above the glass transition temperature, cooling with applied deformation, and subsequent recovery under heat treatment. These findings are planned to be used in a future study on finger orthoses that could either be printed according to shape or in a flat shape and afterwards heated and bent around the finger.

Sign in / Sign up

Export Citation Format

Share Document