Nanocomposite Filaments Research Articles

Mechanical behavior of additively manufactured nanoclay/HDPE nanocomposites

Nanoclay (NC) has blended with relatively inexpensive, widely consumed HDPE (high density polyethylene) for the development of filament to be used in 3D printers. NC/HDPE blends are prepared by varying NC wt. % (0.5, 1, 2, and 5) and are subjected to melt flow index (MFI) measurements. MFI has noted to be decreasing with NC loadings. NC/HDPE nanocomposite blends are further extruded using a single screw extruder. Developed nanocomposites filaments are fed to the fused filament fabrication (FFF) based 3D printer for realizing NC/HDPE nanocomposite prints. The density of printed sample increases with filler content. Filament and printed samples thermal study is carried out using differential scanning calorimeter (DSC). NC addition increases crystallinity and crystallization temperature without significant change in melting peak temperature. Freeze fractured prints reveal the uniform distribution of NC in HDPE. The tensile test is conducted on the filaments and prints. Further printed nanocomposites are subjected to flexural investigations. Tensile modulus and strength of filament increase with NC additions in HDPE matrix. Tensile and flexural properties (modulus and strength) of the nanocomposite prints increases with NC content. Finally, results obtained from the tensile and flexural tests of prints are compared with different HDPE composites available in the literature.

Mechanical and Electrical Properties Investigation of 3D-Printed Acrylonitrile–Butadiene–Styrene Graphene and Carbon Nanocomposites

Acrylonitrile–butadiene–styrene (ABS) nanocomposite filaments for 3D-printing were produced by melt compounding and extrusion. Two types of nanoadditives were employed: (a) graphene nanoplatelets (GnP) at various concentrations and (b) carbon nanotubes (CNTs). Fused filament fabrication (FFF) 3D printer was used for the fabrication of specimens, according to international standards to be employed for the determination of the tension and flexural mechanical properties of the specimens and the correlation with their microstructure. Nanocomposite filaments were also tested in tension, to evaluate the effect of 3D printing on the material. Moreover, the electrical properties of the specimens were also determined. As found out, a decrease in the tensile strength, the tensile modulus of elasticity, the flexural strength, and the flexural modulus of elasticity can be observed with the increase in the GnP concentration, in every case. ABS specimens filled with CNTs exhibited higher tensile and flexural strength and a more brittle behavior when compared to pure ABS and ABS with GnP. Regarding the electrical properties of the composites, it was found that dielectric constant increases by increasing GnP content, the specimens remaining at the same time rather nonconductive, even at a concentration of 10 wt.% in GnP. In contrast, ABS filled with CNTs at a concentration of 10% illustrated a large conductivity.

Mechanical properties of nanocomposite biomaterials improved by extrusion during direct ink writing

In this study, single filaments of acrylated epoxidized soybean oil (AESO)/polyethylene glycol diacrylate (PEGDA)/nanohydroxyapatite (nHA)-based nanocomposites intended for bone defect repair have displayed significant improvement of their mechanical properties when extruded through smaller needle gauges before UV curing. These nanocomposite inks can be deposited layer-by-layer during direct ink writing (DIW) – a form of additive manufacturing.Single filaments were prepared by extruding the nanocomposite ink through needles with varying diameters from 0.21 mm to 0.84 mm and then UV cured. Filaments and cast specimens were tensile tested to determine elastic modulus, strength and toughness. The cured nanocomposite filaments were further characterized using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM).SEM confirmed that the hydroxyapatite nanoparticles were well dispersed in the polymer matrices. The ultimate tensile strength and moduli increased as the diameter of the extrusion needle was decreased. These correlated with increased matrix crystallinity and fewer defects. For instance, filaments extruded through 0.84 mm diameter needles had ultimate tensile stress and modulus of 26.3 ± 2.8 MPa and 885 ± 100 MPa, respectively, whereas, filaments extruded through 0.21 mm needles had ultimate tensile stress and modulus of 48.9 ± 4.0 MPa and 1696 ± 172 MPa, respectively.This study has demonstrated enhanced mechanical properties resulting from extrusion-based direct ink writing of a new AESO-PEGDA-nHA nanocomposite biomaterial intended for biomedical applications. These enhanced properties are the result of fewer defects and increased crystallinity. A means of achieving mechanical properties suitable for repairing bone defects is apparent.

Graphene/Carbon Nanotube Hybrid Nanocomposites: Effect of Compression Molding and Fused Filament Fabrication on Properties.

The present work reports on the production and characterization of acrylonitrile butadiene styrene (ABS) hybrid nanocomposite filaments incorporating graphene nanoplatelets (GNPs) and carbon nanotubes (CNTs) suitable for fused filament fabrication (FFF). At first, nanocomposites with a total nanofiller content of GNP and/or CNT of 6 wt.% and a GNP/CNT relative percentage ratio of 0, 10, 30, 50, 70, and 100 were produced by melt compounding and compression molding. Their mechanical, electrical resistivity, and electromagnetic interference shielding effectiveness (EMI SE) properties were evaluated. The hybrid nanocomposites showed a linear increase in modulus and decrease in strength as a function of GNP content; on the other hand, the addition of CNT in hybrid nanocomposites determined a positive increase in electrical conductivity, but a potentially critical decrease of melt flow index. Due to the favorable compromise between processability and enhancement of performance (i.e., mechanical and electrical properties), the hybrid composition of 50:50 GNP/CNT was selected as the most suitable for the filament production of 6 wt.% carbonaceous nanocomposites. EMI SE of ABS-filled single CNT and hybrid GNP/CNT nanofillers obtained from compression molding reached the requirement for applications (higher than −20 dB), while slightly lower EMI SE values (in the range −12/−16 dB) were obtained for FFF parts dependent on the building conditions.

Effects of Filament Extrusion, 3D Printing and Hot-Pressing on Electrical and Tensile Properties of Poly(Lactic) Acid Composites Filled with Carbon Nanotubes and Graphene.

In this study, the effects of three processing stages: filament extrusion, 3D printing (FDM), and hot-pressing are investigated on electrical conductivity and tensile mechanical properties of poly(lactic) acid (PLA) composites filled with 6 wt.% of multiwall carbon nanotubes(MWCNTs), graphene nanoplatelets (GNPs), and combined fillers. The filaments show several decades’ higher electrical conductivity and 50–150% higher values of tensile characteristics, compared to the 3D printed and the hot-pressed samples due to the preferential orientation of nanoparticles during filament extrusion. Similar tensile properties and slightly higher electrical conductivity are found for the hot-pressed compared to the 3D printed samples, due to the reduction of interparticle distances, and consequently, the reduced tunneling resistances in the percolated network by hot pressing. Three structural types are observed in nanocomposite filaments depending on the distribution and interactions of fillers, such as segregated network, homogeneous network, and aggregated structure. The type of structural organization of MWCNTs, GNPs, and combined fillers in the matrix polymer is found determinant for the electrical and tensile properties. The crystallinity of the 3D printed samples is higher compared to the filament and hot-pressed samples, but this structural feature has a slight effect on the electrical and tensile properties. The results help in understanding the influence of processing on the properties of the final products based on PLA composites.

Interfacial Nanoparticle Complexation of Oppositely Charged Nanocelluloses into Functional Filaments with Conductive, Drug Release, or Antimicrobial Property.

Construction of colloidal nanoparticles (NPs) into advanced functional nanocomposites and hybrids with the predesigned hierarchical structure and high-performance is attractive, especially for natural biological nanomaterials, such as proteins and polysaccharides. Herein, a simple and sustainable approach called interfacial NP complexation (INC) was applied to construct diverse functional (conductive, drug-loaded, or antimicrobial) nanocomposite filaments from oppositely charged colloidal nanocelluloses. By incorporating different additives during the INC process, including multiwalled carbon nanotube, an antitumor drug (doxorubicin hydrochloride), and metal (silver) NPs (Ag NPs), high-performance functional continuous filaments were synthesized, and their potential applications in electronics, drug delivery, and antimicrobial materials were investigated, respectively. This novel INC method based on charged colloidal NPs opens new avenues for building various functional filaments for a diversity of end uses.

Fibrous PEBA-graphene nanocomposite filaments and membranes fabricated by extrusion and additive manufacturing

Polyether block amide (PEBA) and PEBA based nanocomposites are one of the most promising materials in environmental technology, used for separation and filtration. Applications of Pebax are studied extensively, however, most of the previous studies focused on its use as a dense membrane without giving due attention to fibrous membranes. This research presents a novel approach to prepare fibrous PEBA Nanocomposite (PNC) membranes while giving special attention to achieving uniform nanomaterial dispersion and applicability of the technology on an industrial scale. For that purpose, extrusion process was used to prepare PNC filaments in the presence of 0.2 wt% of Paraffin Liquid (adhesive layer) and 0.05–0.4 wt% of Graphene (nanofiller material with high aspect ratio). The prepared filaments were spun into fibrous membranes using melt electrospinning as environmentally-friendly additive manufacturing technology. The spinning process was performed with a constant collector diameter (150 mm), at different drum rotational speeds (30–60 rpm), and different spinning temperatures (160–180 °C, based on the Graphene concentration) to study the effect of these conditions on the morphology of the formulated PNC membranes. Potential applications of the produced PNC membranes in the cleanup of oil spills were studied. Morphology and dispersion of the obtained PNC filaments and membranes were investigated by SEM and TEM. Chemical, thermal, and mechanical properties were studied using XRD, FTIR, TGA, DSC, and universal testing machine. The results showed that in both cases (PNC filaments and fibrous membranes) at 0.3 wt% of Graphene material with optimum properties, such as uniform dispersion, high tensile strength, elastic modulus, melting temperature, crystallinity degree (65% improvement in filaments and 58% improvement in fibrous membranes compared with pure PEBA), and low plasticity was achieved. Spinning results showed that aligned fibers with an average diameter 5 μm were produced at the highest rotational speeds (such fibers can be used in textiles) while at the lowest speeds cross-linked microfibers in form of membrane with small inter-fiber pores were produced (the membranes can be used in cleanup of oil spills). The developed approach for preparation of nanocomposite filaments can be used to produce raw material for melt spinning or 3D Printing in general.

Production and characterization of PEEK/IF-WS2 nanocomposites for additive manufacturing: Simultaneous improvement in processing characteristics and material properties

Successful printing of high-performance material with suitable properties using additive manufacturing methods such as Fused Filament Fabrication (FFF) can create many advanced applications in industries. However, the high viscosity of high-performance polymers causes complications during the FFF process and reduces the final print quality. To overcome this challenge, Inorganic Fullerene Tungsten Sulphide (IF-WS2) nanoparticles are applied in this study to enhance the flowability of poly-ether-ketone-ketone (PEEK) without compromising its mechanical and thermal properties. In the first step, different loadings of IF-WS2 nanoparticles are melt compounded with PEEK and the nanocomposites are characterized. SEM and EDX images of fractured surfaces indicate that a good dispersion of nanoparticles is achieved without any pre-treatment or pre-dispersion. A reduction in melt viscosity of 25%, and a simultaneous growth in storage modulus, crystallization and degradation temperature of about 60%, 53% and 100 °C is found with addition of 2 wt% IF-WS2 to PEEK, respectively. This great achievement is mainly ascribed to the unique characteristics of IF-WS2 nanoparticles, acting as both reinforcing and lubricating agents, indicated by a reduction in coefficient of friction. There is no significant increase of crystallization and melting temperatures with the addition of IF-WS2 nanoparticles, which is beneficial in the FFF process. In the second step, the PEEK nanocomposite filaments are printed via FFF. The print quality and mechanical properties of the printed PEEK are also improved with the incorporation of IF-WS2 nanoparticles. Hence, incorporation of IF-WS2 nanoparticles into PEEK via melt compounding is an effective approach for the development of suitable high-performance engineering materials for FFF.

Tensile Performance of Fused Deposition Modeling PA 6 Polymer Composites With Nanoparticle Reinforcement and/or Continuous Fiber Reinforcement

AbstractFused deposition modeling (FDM) printing of continuous fiber reinforced polymers had been a challenge until about 5 years ago. With the reinforcement of continuous fiber, the mechanical properties of FDM printed polymers are improved by leaps and bounds. In this paper, we aim to investigate the possibility of further improvement in the mechanical properties of three-dimensional (3D) printed continuous fiber reinforced polymers by adding nanoreinforcements to the polymer matrix. Kevlar fiber is selected as the continuous fiber reinforcement, nylon 6 (PA 6) is selected as the polymer matrix material, and carbon nanotubes (CNTs) or graphene nanoplatelets (GNPs) nanoparticles are selected as the nanoreinforcements. In the experiment, CNT or GNP nanoparticles are first mixed with nylon 6 pellets to make nanocomposites, the nanocomposites are then extruded into filaments for 3D printing, and finally, both Kevlar filament and nanocomposite filament are fed through the printing nozzle and deposited on the platform. Tensile specimens are directly printed from pure PA 6 and three types of nanocomposites, namely, CNT/PA 6, GNP/PA 6, and GNP-NH2/PA 6, as well as Kevlar fiber reinforced PA 6 and three types of Kevlar fiber reinforced nanocomposites. The results indicate that although Kevlar fibers dominate the enhancement of mechanical properties for the printed composite materials, the existence of GNP nanofillers also provide a noticeable contribution to the enhancement of tensile strengths and moduli, while the effect of CNTs is much less pronounced.

In situ prepared polyamide 6/DOPO-derivative nanocomposite for melt-spinning of flame retardant textile filaments

A novel flame retardant polyamide 6 (PA6)/bridged 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)-derivative (PHED) nanocomposite textile filament yarns were developed. The scalable production approach includes in situ water-catalyzed ring-opening polymerization of ε-caprolactam in the presence of the flame retardant PHED followed by melt-spinning of nanocomposite filament yarns and production of knitted fabrics. The specific chemical structure of the PHED additive enabled its excellent miscibility with molten ε-caprolactam and the uninterrupted polymerization of ε-caprolactam. The produced PA6/PHED nanocomposite was characterized by the preserved molecular structure of the polyamide 6 and uniformly distributed nano-dispersed FR at concentrations of 10 and 15 wt %. The PA6/PHED nanocomposite structure was successfully preserved after the melt-spinning processing. The PA6 nanocomposite filament yarns at the applied 15 wt %. loading of PHED showed (a) increased thermo-oxidative stability compared to neat PA6 up to 500 °C, with a 43% higher residue at 500 °C and (b) self-extinguishment of fiber strand and knitted samples within 1 s in standard vertical flame spread tests (ASTM D6413), followed by the significant reduction of the melt-dripping and the melt-drop flammability. Additionally, 1.2 mm-tick PA6/PHED bar samples achieved a V0 rating in UL94 vertical burning test at the applied 10 wt % concentration of PHED. This innovative and scalable approach could pave the way for the production of new-generation nanocomposite PA6 filament yarns with self-extinguishing properties at the macro-scale, which would be highly beneficial for increasing fire safety, whilst maintaining the use of a DOPO derivative at the minimum level.

Extrudable hydroxyapatite/plant oil-based biopolymer nanocomposites for biomedical applications: Mechanical testing and modeling

Towards developing bone-inspired, high performance composite biomaterials, two nanocomposite inks, consisting of a plant oil-based biopolymer resin (soybean oil epoxidized acrylate (SOEA)) and silanized nano-hydroxyapatite (Si-nHA) particles with and without diluent hydroxyethyl acrylate (HEA), were extruded using direct ink writing to fabricate filaments of differing volume fractions. HEA was hypothesized to lower ink viscosity, improve Si-nHA dispersion and extrudability, and therefore result in better relative improvements in mechanical properties over those of the base resin. Thermogravimetric analysis, scanning electron microscopy and uniaxial tensile tests were conducted. Strength, toughness, and stiffness of both resins were improved by the addition of Si-nHA. The HEA improved dispersion and extrudability. This resulted in better particle alignment and relatively greater augmentation of mechanical properties. The experimental data for both biopolymer resins were used to calibrate 3D representative volume element (RVE) finite element micromechanical models, while the experimental data for the nanocomposite filaments were employed to validate these models. The Young's moduli from the computational models were also compared with experimental data and with analytical predictions calculated using the Mori-Tanaka method. The predictions of 3D RVE models correlated well with the experimental data while, for higher volume fractions, the Mori-Tanaka results diverged, similar to previous reports.

VOC Emissions and Formation Mechanisms from Carbon Nanotube Composites during 3D Printing.

A commercially available, 3D printer nanocomposite filament of carbon nanotubes (CNTs) and acrylonitrile-butadiene-styrene (ABS) was analyzed with respect to its VOC emissions during simulated fused deposition modeling (FDM) and compared with a regular ABS filament. VOC emissions were quantified and characterized under a variety of conditions to simulate the thermal degradation that takes place during FDM. Increasing the residence time and temperature resulted in significant increases in VOC emissions, and the oxygen content of the reaction gas influenced the VOC profile. In agreement with other studies, the primary emitted VOC was styrene. Multiple compounds are reported in this work for the first time as having formed during FDM, including 4-vinylcyclohexene and 2-phenyl-2-propanol. Our results show that printing 222.0 g of filament is enough to surpass the reference concentration for inhalation exposure of 1 mg/m3 according to the EPA's Integrated Risk Information System (IRIS). The presence of CNTs in the filament influenced VOC yields and product ratios through three types of surface interactions: (1) adsorption of O2 on CNTs lowers the available O2 for oxidation of primary backbone cleavage intermediates, (2) adsorption of styrene and other VOCs to CNTs leads to surface-catalyzed degradation, and (3) CNTs act as a trap for certain VOCs and prevent them from entering vapor emissions. While the presence of CNTs in the filament lowered the total VOC emission under most experimental conditions, they increased the emission of the most hazardous VOCs, such as α-methylstyrene and benzaldehyde. The present study has identified an increased risk associated with the use of CNT nanocomposites in 3D printing.

Transport properties of 3D printed polymer nanocomposites for potential thermoelectric applications

We report the transport and thermoelectric properties of three-dimensional printed samples, which are composed by polymer nanocomposites. For the purposes of the current study, the well-known fused deposition modeling three-dimensional printing method was employed. Commercially available PLA-based nanocomposite filaments, such as PLA–graphite and PLA–graphene, are used to produce mm-scale samples. Electrical conductivity and Seebeck coefficient were investigated, as a function of temperature. PLA–graphene samples exhibit effective thermoelectric performance, comparable to the other state-of-the art polymer nanocomposites, indicating that commercial polymer nanocomposites can be promising candidates for 3D printed thermoelectric devices.

Heterophase materials for fused filament fabrication of structural electronics

In this work, new electrically conductive composite filaments are developed for the fabrication of conductive paths, 3D printed with FDM technology. These composite materials consist of electrically conductive copper powder and a polymer matrix. The influence of three different polymers (ABS, PLA, PS) on the electrical properties of the composites was examined. Electrical measurements of the composite filaments with the increasing copper powder concentrations, allow identifying the percolation threshold for elaborated composites. Results show that the lowest resistivity (0.156 × 10−5 Ωm) was achieved for the ABS/Cu composite at the 84.6 wt% Cu concentration. The obtained resistivity values are much lower than for other conductive composites and nanocomposites filaments reported in the literature. Voltage-current characteristics determined for each composite material showed that composites have Ohmic characteristics in low voltage regime. At high voltage regime, the electrical power dissipated in the composites caused a rapid increase in temperature. It was discovered that a polymer matrix influences the maximum value of the electrical power that can be dissipated in the filament before losing electrical conductivity. Examples of conductive 3D printed structures made from elaborated composites are also presented.

Interfacial interactions in PMMA/silica nanocomposites enhance the performance of parts created by Fused Filament Fabrication

As an additive manufacturing method, Fused Filament Fabrication (FFF) is conceptually attractive due to its agility and adaptability. However, FFF-printed parts exhibit poor mechanical properties as compared to parts manufactured by traditional methods. Here, the addition of silica nanoparticles (Si NPs) into FFF-printed parts is demonstrated to markedly improve a variety of thermomechanical properties. Specifically, dynamic mechanical analysis (DMA) and tensile tests indicate that the glass transition temperature, Young's modulus, elongation at break, ultimate tensile strength, and storage and loss moduli all increase with the Si NP loading. Small-angle X-ray scattering (SAXS) and scanning electron microscopy (SEM) demonstrate similar hierarchical structures in all FFF-printed nanocomposites, which suggests that improvements in material properties with Si NP loading are likely due to an increasing number of hydrogen bonding interactions between PMMA matrix chains and hydroxyl groups on the Si NP surface. The potential of nanocomposite filaments to increase the thermomechanical properties of FFF-printed specimens provides a facile route to overcome limitations in FFF-printed part strength by combining the properties of hard and soft matter.

Restructuring of confined crystalline morphology in the drawing process of VGCF-iPP nanocomposite filaments

Solid-state drawing to high extension ratios of melt-extruded VGCF-iPP nanocomposite filaments results in remarkable increases in modulus and strength, which mask any contribution of nano-reinforcement or inter-particle confinement observed previously. Based on X-ray diffraction and thermal analyses it is shown that the drawing process involves crumpling of the original 'shish-kebab' structure, accompanied by lateral shrinkage of the 'kebabs', disappearance and reorientation of daughter lamellae and significant increases in the degree of crystallinity by solid-state recrystallization. The effects of the initial diameter of the as-extruded filaments and those of the nanofibers and the 'shish-kebab' structure are dominated by the drawing process, which produces a highly aligned fibrillar structure with superior mechanical properties. A cartoon model of the effect of solid-state drawing of extruded iPP and nanocomposite filaments on the transition from 'shish-kebab' to fibril morphology is presented.

Antimicrobial Activity of PET-Silver Nanocomposite Filaments

This study evaluated the antimicrobial activity of PET-Silver nanocomposite filaments at different concentrations (0, 0.180%, 0.135%, 0.090%, 0.045% and 0.022% w/w) of silver nanoparticles in order to determine the minimum inhibitory concentration and minimum bactericidal concentration of silver incorporated in the PET matrix. The in vitro antibacterial activity was evaluated by the AATCC standard 100: 2012 method, against Staphylococcus aureus ATCC 6538, and Klebsiella pneumonia ATCC 4532. The filaments were tested after one and twenty-one months of preparation to evaluate the effect of time on the antimicrobial activity of the nanocomposites. Moreover, the antimicrobial activity was also evaluated after dyeing the filaments. The silver-free PET filaments have not demonstrated antimicrobial activity and cytotoxicity against human dermal fibroblasts. Nevertheless, excepted for the filament with 0.022% of silver nanoparticles, all PET-Silver nanocomposites reduced more than 99% the colony-forming units (CFU) of Staphylococcus aureus and Klebsiella pneumonia after one and twenty-one months of preparation. This suggests that the MIC of silver nanoparticles incorporated in the PET matrix is lower than 220 ppm (w/w) and the MBC is between 0.022 and 0.045% (w/w). However, after the dyeing process, no antimicrobial activity was observed for any PET-Silver nanocomposite filaments. This may be attributed to the release of silver from the PET matrix during the dyeing process or to the reaction/inactivation of the silver ions by the salts used in this chemical treatment.

Electrically Conductive Polyetheretherketone Nanocomposite Filaments: From Production to Fused Deposition Modeling.

The present work reports the production and characterization of polyetheretherketone (PEEK) nanocomposite filaments incorporating carbon nanotubes (CNT) and graphite nanoplates (GnP), electrically conductive and suitable for fused deposition modeling (FDM) processing. The nanocomposites were manufactured by melt mixing and those presenting electrical conductivity near 10 S/m were selected for the production of filaments for FDM. The extruded filaments were characterized for mechanical and thermal conductivity, polymer crystallinity, thermal relaxation, nanoparticle dispersion, thermoelectric effect, and coefficient of friction. They presented electrical conductivity in the range of 1.5 to 13.1 S/m, as well as good mechanical performance and higher thermal conductivity compared to PEEK. The addition of GnP improved the composites’ melt processability, maintained the electrical conductivity at target level, and reduced the coefficient of friction by up to 60%. Finally, three-dimensional (3D) printed test specimens were produced, showing a Young’s modulus and ultimate tensile strength comparable to those of the filaments, but a lower strain at break and electrical conductivity. This was attributed to the presence of large voids in the part, revealing the need for 3D printing parameter optimization. Finally, filament production was up-scaled to kilogram scale maintaining the properties of the research-scale filaments.

3D structured nanocomposites by FDM process: a novel approach for large-scale photocatalytic applications

In this work, we report for the first time the fabrication of nanocomposite polystyrene filaments enriched with ZnO and TiO2 nanoparticles with mass concentrations up to 20%w/w, and the production of 3D photocatalytic structures using a typical FDM-type 3D printer. We provide evidence that the fabricated 3D structures offer promising photocatalytic properties, reaching an efficiency of almost 70% after five cycles of reuse in 20 ppm of Methylene Blue aqueous solution, under UV irradiation. Thus, a novel low-cost alternative route for fabricating large-scale photocatalysts, suitable for practical real-life applications, is proposed.

Investigation of polylactide and carbon nanocomposite filament for 3D printing

Fused deposition modeling (FDM) has been used to manufacture complicated structures and robots in the past few years. However, most FDM machines do not fabricate fully functional robots that are ready for use. One of the requirements of fully functional 3D printed robots is electrical connection in some part of the printed structure. Recently, electrically conductive commercial filaments are emerging to the market, but the actual chemical compositions of the filler and host materials as well as mechanical properties are not available. This paper presents composite materials consisting of conductive carbon nanoparticles, thermoplastics, and solvents to create thin filaments for 3D printing. The mechanical and electrical properties of the filaments fabricated using a composition of 0–15% weight of carbon nanoparticles (NC) in polylactide (PLA) and dichloromethane (DCM) solvent were investigated. The DCM is used for dissolving the PLA and dispersion of the NC, which is subsequently evaporated by drying. The electrical conductivity of the composite filament is compared with commercial and academia counterparts. Possible applications of the composite materials for fabrication of electrical circuitry for 3D printed robots were also discussed.