scholarly journals Advanced mechanical and thermal characterization of 3D bioextruded poly(e-caprolactone)-based composites

2018 ◽  
Vol 24 (4) ◽  
pp. 731-738 ◽  
Author(s):  
Hanxiao Wang ◽  
Marco Domingos ◽  
Fabio Scenini
Keyword(s):  
Mechanical Performance ◽  
Raw Materials ◽  
Thermal Characterization ◽  
Nano Particles ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Content Type ◽  
Bioactive Scaffolds ◽  
3D Printed ◽  
Mechanical Performances

Purpose The purpose of this paper is to study the effect of nano hydroxyapatite (HA) and graphene oxide (GO) particles on thermal and mechanical performances of 3D printed poly(ε-caprolactone) (PCL) filaments used in bone tissue engineering (BTE). Design/methodology/approach Raw materials were prepared by melt blending, followed by 3D printing via 3D Discovery (regenHU Ltd., CH) with all fabricating parameters kept constant. Filaments, including pure PCL, PCL/HA and PCL/GO, were tested under the same conditions. Several techniques were used to mechanically, thermally and microstructurally evaluate properties of these filaments, including differential scanning calorimetry, tensile test, nano indentation and scanning electron microscope. Findings Results show that both HA and GO nano particles are capable of improving mechanical performance of PCL. Enhanced mechanical properties of PCL/HA result from reinforcing effect of HA, while a different mechanism is observed in PCL/GO, where degree of crystallinity plays an important role. In addition, GO is more efficient at enhancing mechanical performance of PCL compared with HA. Originality/value For the first time, a systematic study about effects of nano HA and GO particles on bioactive scaffolds produced by additive manufacturing for BTE applications is conducted in this work. Mechanical and thermal behaviors of each sample, pure PCL, PCL/HA and PCL/GO, are reported, correlated and compared with literature.

Study of the annealing influence on the mechanical performance of PA12 and PA12 fibre reinforced FFF printed specimens

2020 ◽  
Vol 26 (10) ◽  
pp. 1761-1770
Author(s):  
Isaac Ferreira ◽  
Carolina Melo ◽  
Rui Neto ◽  
Margarida Machado ◽  
Jorge Lino Alves ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Flexural Modulus ◽  
Tensile Modulus ◽  
Annealing Treatment ◽  
Degree Of Crystallinity ◽  
Fibre Reinforcement ◽  
Scanning Calorimetry ◽  
Content Type ◽  
The Degree Of Crystallinity

Purpose The purpose of this study is to evaluate and compare the mechanical performance of FFF parts when subjected to post processing thermal treatment. Therefore, a study of the annealing treatment influence on the mechanical properties was performed. For this, two different types of Nylon (PA12) were used, FX256 and CF15, being the second a short fibre reinforcement version of the first one. Design/methodology/approach In this study, tensile and flexural properties of specimens produced via FFF were determined after being annealed at temperatures of 135°C, 150°C or 165°C during 3, 6, 12 or 18 h and compared with the non-treated conditions. Differential scanning calorimetry (DSC) was performed to determine the degree of crystallinity. To evaluate the annealing parameters’ influence on the mechanical properties, a full factorial design of experiments was developed, followed by an analysis of variance, as well as post hoc comparisons, to determine the most significative intervening factors and their effect on the results. Findings The results indicate that CF15 increased its tensile modulus, strength, flexural modulus and flexural strength around 11%, while FX256 presented similar values for tensile properties, doubling for flexural results. Flexural strain presented an improvement, indicating an increased interlayer behaviour. Concerning to the DSC analysis, an increase in the degree of crystallinity for all the annealed parts. Originality/value Overall, the annealing treatment process cause a significant improvement in the mechanical performance of the material, with the exception of 165°C annealed specimens, in which a decrease of the mechanical properties was observed, resultant of material degradation.

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.

Characterization of nano-enhanced interconnect materials for fine pitch assembly

2014 ◽  
Vol 26 (1) ◽  
pp. 12-17 ◽  
Author(s):  
Yan Zhang ◽  
Janusz Sitek ◽  
Jing-yu Fan ◽  
Shiwei Ma ◽  
Marek Koscielski ◽  
...  
Keyword(s):  
Filler Content ◽  
Nano Particles ◽  
Differential Scanning Calorimetry Measurement ◽  
Conductive Adhesives ◽  
Scanning Calorimetry ◽  
Loading Test ◽  
Content Type ◽  
Fine Pitch ◽  
Silver Flakes ◽  
Silver Spheres

Purpose – Multiple fillers are adopted to study the filler influences on electrical and mechanical properties of the conductive adhesives. The performances of the developed nano-enhanced interconnect materials in printing process are also evaluated. The paper aims to discuss these issues. Design/methodology/approach – Micron-sized silver flakes are used as the basic fillers, and submicro- and nano-sized silver spheres and carbon nanotubes (CNTs) are adopted to obtain conductive adhesives with multiple fillers. Differential scanning calorimetry measurement is carried out to characterize the curing behavior of the samples with different fillers, four-probe method is used to obtain the bulk resistivity, shear test is conducted for adhesive strength, and environmental loading test is also involved. Furthermore, printing trials with different patterns have been carried out. Findings – The electrical resistivity of the adhesives with submicro-sized silver spheres does not monotonically change with the increasing sphere proportion, and there exists an optimized value for the ratio of silver flakes to spheres. Samples with relatively small amount of CNT additives show improved electrical properties, while their mechanical strengths tend to decrease. For the printing application, the adhesives with 18.3 volume% filler content behave much better than those with lower filler content of 6 percent. The presence of the nano-particles makes a slight improvement in the printing results. Research limitations/implications – More detailed printing performance and reliability test of the samples need to be carried out in the future. Originality/value – The conductive adhesives as interconnect materials exhibit some improved properties with optimized bimodal or trimodal fillers. The additive of the nano-fillers affects slightly on the printing quality of the bimodal conductive adhesives.

Soft-tissue-mimicking using silicones for the manufacturing of soft phantoms by fresh 3D printing

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Aitor Tejo-Otero ◽  
Arthur Colly ◽  
Edwin-Joffrey Courtial ◽  
Felip Fenollosa-Artés ◽  
Irene Buj-Corral ◽  
...  
Keyword(s):  
Soft Tissue ◽  
3D Printing ◽  
Three Dimensional ◽  
Mechanical Analysis ◽  
Living Tissue ◽  
Scanning Calorimetry ◽  
Content Type ◽  
Microscopy Analysis ◽  
3D Printed ◽  
Liver Phantom

Purpose The purpose of this study is to use the Freeform Reversible Embedding of Suspended Hydrogels (FRESH) additive manufacturing (AM) technique for manufacturing a liver phantom which can mimic the corresponding soft living tissue. One of the possible applications is surgical planning. Design/methodology/approach A thermo-reversible Pluronic® F-127-based support bath is used for the FRESH technique. To verify how three-dimensional (3D)-printed new materials can mimic liver tissue, dynamic mechanical analysis and oscillation shear rheometry tests are carried out to identify mechanical characteristics of different 3D printed silicone samples. Additionally, the differential scanning calorimetry was done on the silicone samples. Then, a validation of a 3D printed silicone liver phantom is performed with a 3D scanner. Finally, the surface topography of the 3D printed liver phantom was fulfiled and microscopy analysis of its surface. Findings Silicone samples were able to mimic the liver, therefore obtaining the first soft phantom of the liver using the FRESH technique. Practical implications Because of the use of soft silicones, surgeons could practice over these improved phantoms which have an unprecedented degree of living tissue mimicking, enhancing their rehearsal experience before surgery. Social implications An improvement in surgeons surgery skills would lead to a bettering in the patient outcome. Originality/value The first research study was carried out to mimic soft tissue and apply it to the 3D printing of organ phantoms using AM FRESH technique.

Investigation on selective laser sintering of PA12: dimensional accuracy and mechanical performance

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Achille Gazzerro ◽  
Wilma Polini ◽  
Luca Sorrentino
Keyword(s):  
Mechanical Performance ◽  
Selective Laser Sintering ◽  
Central Zone ◽  
Dimensional Accuracy ◽  
Laser Sintering ◽  
Point Of View ◽  
Content Type ◽  
Mechanical Performances ◽  
The Many ◽  
Additional Support

Purpose Selective laser sintering (SLS) has passed other techniques, thanks to its high print resolution, its ability to print microscale geometries without any additional support, its surface quality and its long-term thermal stability. However, despite the many advantages of SLS compared to fusion deposition modelling, there are still today some limitations on the materials to be printed. A limit critical from an industrial point of view is the aging of PA12 powder, i.e. the degradation of its physical and chemical performances, due to the high temperatures and the long printing cycles, thus involving a decrease of the mechanical properties of the printed parts. The purpose of this study was to charaterize mechanically and dimensionally specimens printed in PA12 through SLS by means of virgin or aged powder, i.e. powder just used for five printing cycles. Design/methodology/approach To achieve this aim, a set of specimens were designed, built, measured and mechanically tested; the obtained results were put into relationship with the values of the process parameters used to print them. Statistical tools to design the experiments and to analyse the obtained results were used. Findings The results show that the SLS process carried out through a Sintratec machine on PA12 powder has a good repeatability. To obtain the best dimensional and mechanical performances, it is needed to use virgin powder and place the part in the central zone of the printing area. Originality/value There are no scientific articles dealing with the influence of both the aging of the powder and the manufacturing parameters on the dimensional and mechanical characterization of specimens printed with SLS technique in PA12.

Ultra-high Molecular Weight Polyethylene /Graphite Nanocomposites Prepared by High-energy Cryomilling.

2013 ◽  
Vol 1453 ◽  
Author(s):  
Sofía Vazquez-Rodriguez ◽  
Gloria E. Rodríguez-Vázquez ◽  
Selene Sepulveda-Guzman ◽  
Martín E. Reyes-Melo ◽  
Aaron Morelos-Gomez ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Mechanical Performance ◽  
Thermal Characterization ◽  
High Energy ◽  
Graphite Nanoplatelets ◽  
Scanning Calorimetry ◽  
Ultra High Molecular Weight ◽  
Graphite Nanocomposites

ABSTRACTUltra-high molecular weight polyethylene/graphite nanocomposites were prepared by high-energy cryogenic milling followed by syntering. Microstructure changes shows that graphite was reduced to graphite nanoplatelets by high-energy cryomilling and partial exfoliation of graphite to few layered graphene nanoplatelets occurred in a small extent. The resulting nanocomposites revealed high electrical conductivity and good mechanical performance. Thermal characterization of the nanocomposites was also carried out by differential scanning calorimetry.

scholarly journals Thermoplastic Starch (TPS) Films Added with Mucilage from Opuntia Ficus Indica: Mechanical, Microstructural and Thermal Characterization

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 1000 ◽  
Author(s):  
Fabrizio Scognamiglio ◽  
Daniele Mirabile Gattia ◽  
Graziella Roselli ◽  
Franca Persia ◽  
Ugo De Angelis ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Potato Starch ◽  
Thermal Characterization ◽  
Thermoplastic Starch ◽  
Vegetable Waste ◽  
Scanning Calorimetry ◽  
Plasticization Effect ◽  
Magnesium Salts ◽  
The One ◽  
Loading Modes

Opuntia cladodes are a typical vegetable waste, from which mucilage in gel form can be extracted. This work proposes blending it with a self-produced thermoplastic starch (TPS), originating from potato starch with a high content in glycerol (ca. 30%). Three methods were compared for extraction, bare maceration (MA), mechanical blending (ME) and mechanical blending following maceration (MPM) to produce films with an approximate thickness of 150 μm. For the comparison, tensile testing, differential scanning calorimetry and scanning electron microscopy were used. The MPM process proved the most effective, not only for extraction yielding, but also to obtain a larger deformation of the samples with respect to the one allowed by the pure TPS films. A considerable plasticization effect was observed. Despite this, the mechanical performance is still not completely satisfactory, and the expected effect of the calcium and magnesium salts contained in the mucilage to improve the rigidity of the TPS film was not really revealed. Prospected improvements would concern the fabrication process and the investigation of other possible loading modes and sample geometries.

scholarly journals Selective laser melting using holographic beam manipulation: influence of polypropylene molecular weight

2018 ◽  
Vol 24 (1) ◽  
pp. 93-105 ◽  
Author(s):  
Barry Haworth ◽  
John R. Tyrer ◽  
Zhou Zhou
Keyword(s):  
Molecular Weight ◽  
Selective Laser Melting ◽  
Mechanical Performance ◽  
Analytical Techniques ◽  
Polymeric Materials ◽  
Laser Melting ◽  
Scanning Calorimetry ◽  
Content Type ◽  
Potential Use ◽  
Beam Manipulation

Purpose There is a requirement to match selective laser melting (SLM) technologies to a wider range of polymeric materials, as the existing market for SLM powders is dominated by polyamide PA12. Drivers include the tailoring of physical properties to individual applications or cost reduction. Polypropylene (PP) currently has limited use in SLM; so, this paper aims to explore the potential use of PP materials of varying molecular weight (Mw). Design/methodology/approach PP polymers of differing Mw were characterised using a range of analytical techniques, including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), rotational rheometry and real-time hot-stage (optical) microscopy. Findings The techniques are sufficiently sensitive to distinguish Mw effects, notably in terms of material viscosity. The stable sintering region for SLM has been defined clearly. Some success was achieved in melting parts using all grades of PP, including higher Mw grades, which potentially offer improved mechanical performance. Research limitations/implications The range of techniques (DSC, oxidative induction time and TGA) form an effective analytical package with which to consider new polymeric materials for SLM. Practical implications High-Mw PP polymers, in tape or powder form, have potential use in SLM processes, providing scope to enhance part properties in future. Originality/value This is believed to be the first in-depth study noting the influence of PP Mw on important physical performance in a proprietary SLM process, using holographic beam manipulation.

Spectrally selective nano-absorber pigments

2015 ◽  
Vol 44 (6) ◽  
pp. 347-357
Author(s):  
Fawzia Fahim Abdel-Mohsen ◽  
Hassan Salah Aly Emira
Keyword(s):  
Electron Microscope ◽  
Sol Gel ◽  
Nano Particles ◽  
Nickel Oxides ◽  
Scanning Calorimetry ◽  
Lower Efficiency ◽  
Content Type ◽  
Molar Ratios ◽  
Spectrally Selective ◽  
Cobalt And Nickel

Purpose – The purpose of this study was to prepare colour pigments for use as spectrally selective coatings for solar absorbers. Design/methodology/approach – Nano-particles cobalt and nickel oxides were prepared by sol–gel techniques. These oxides were prepared with its molar ratios and annealed at 200, 400, 600 and 800°C. The structure of the pigments was characterized by infrared spectrometer, differential scanning calorimetry analysis, X-ray diffraction, transmission electron microscope and scanning electron microscope. Findings – Encapsulated cobalt and nickel oxides were completely formed at 800 and 600°C, and its colour was black and dark green, respectively. The results confirmed that black and green pigments combined selectivity with colour. Optical properties such as absorption and reflection were affected by the firing temperatures on cobalt and nickel oxides–gel polymers. All synthesized pigments consisted of nano-particles. Research limitations/implications – The prepared samples used in the present work were synthesized from cobalt chloride and nickel acetate. The salts were dispersed in polyacrylamide as a precursor. Practical implications – The prepared metal oxides had good solar properties. Originality/value – Colour becomes more important for thermal solar collectors, and it has attracted interest. This might be related to a generally growing attention towards architectural integration of solar energy systems into building. Architects would prefer different colours besides black, even if lower efficiency would have to be accepted.

A review on fibre reinforced composite printing via FFF

2019 ◽  
Vol 25 (6) ◽  
pp. 972-988 ◽  
Author(s):  
Isaac Ferreira ◽  
Margarida Machado ◽  
Fernando Alves ◽  
António Torres Marques
Keyword(s):  
High Performance ◽  
Mechanical Performance ◽  
Fused Filament Fabrication ◽  
Content Type ◽  
Performance Improvements ◽  
Different Types ◽  
Significant Research ◽  
Comprehensive Survey ◽  
3D Printed ◽  
Reinforced Thermoplastics

Purpose In industry, fused filament fabrication (FFF) offers flexibility and agility by promoting a reduction in costs and in the lead-time (i.e. time-to-market). Nevertheless, FFF parts exhibit some limitations such as lack of accuracy and/or lower mechanical performance. As a result, some alternatives have been developed to overcome some of these restrictions, namely, the formulation of high performance polymers, the creation of fibre-reinforced materials by FFF process and/or the design of new FFF-based technologies for printing composite materials. This work aims to analyze these technologies. Design/methodology/approach This work aims to study and understand the advances in the behaviour of 3D printed parts with enhanced performance by its reinforcement with several shapes and types of fibres from nanoparticles to continuous fibre roving. Thus, a comprehensive survey of significant research studies carried out regarding FFF of fibre-reinforced thermoplastics is provided, giving emphasis to the most relevant and innovative developments or adaptations undergone at hardware level and/or on the production process of the feedstock. Findings It is shown that the different types of reinforcement present different challenges for the printing process with different outcomes in the part performance. Originality/value This review is focused on joining the most important researches dedicated to the process of FFF-printed parts with different types reinforcing materials. By dividing the reinforcements in categories by shape/geometry and method of processing, it is possible to better quantify performance improvements.

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