Production of 3d printer filament using exfoliated graphene and recycled pp composite and their application to 3d printing

Micro-supercapacitors (MSCs) show great potential as on-chip energy storage devices for portable electronics. The major flaw of thin-film MSCs is their low energy density. To improve the energy density, thicker electrodes are required. However, the fabrication of MSCs with thick electrodes remains a challenge. In this work, a novel 3D printing method is employed to fabricate high-performance MSCs with interdigitated exfoliated graphene (EG)/carbon nanotube (CNT)/silver nanowire (AgNW) electrodes. The nanowelding of AgNW junction plays a critical role in the realization of 3D printing. To enhance the electrochemical performances of EG, phosphorus atoms are incorporated into the carbon framework with 1.7 at%. The areal capacitance of the 3D printed MSC is 21.6 mF cm−2 at a scan rate of 0.01 V s−1. The areal energy density of the MSC ranges from 0.5 to 2 μWh cm−2 with a maximum power density of 2.5 mW cm−2.

The three-dimensional (3D) printing of recycled carbon fiber was demonstrated by the fused filament fabrication technique. A recycled carbon fiber spun yarn was processed into a filament for 3D printing using polyamide 6 and polyamide 12 as the matrix. The fibers were aligned in the axial direction of the filament, and the filament followed the print path during 3D printing. Four specimens were prepared from the filament by 3D printing. The effect of the 3D printing process on the tensile properties of the recycled carbon fiber filament was evaluated. The comparison of the four specimens showed that the 3D-printing process adversely affected the tensile properties of the composite by damaging the fibers and dispersing the fiber direction. Multiplying the filament compensated for the variability in the tensile properties and improved the tensile properties of the 3D-printed coupon. The 3D-printed recycled carbon fiber-reinforced polyamide showed intermediate properties between those of 3D-printed continuous and milled carbon fiber composites. 3D printing is an effective molding technique for the use of recycled carbon fibers.

We present a synergetic combination of two previously separate process technologies to create novel lightweight structures.3D textiles and 3D printing.We will outline the development of a novel material system that consisted of flexible and foldable 3D textiles that are combined with stiff, linear 3D printed materials.Our aim is to produce material-reduced lightweight elements for building applications with an extended functionality and recyclability.Within an ongoing research project (6dTEX), we explore a mono-material system, which uses the same base materials for both the filament for 3D printing and the yarn of the fabrication of the 3D textiles. Based on preliminary 3D printing tests on flat textiles key process parameters were identified. Expertise has been established for 3D printing on textiles as well as for using printable recycled polyester materials (PES textile and PETG filament. Lastly for 3D printing on non-combustible material (alkali-resistant (AR) glass textiles and for 3D concrete printing (3DCP).The described process-knowledge facilitates textile architectures with an extended vocabulary, ranging from flat to single curved and folded topologies.Whereas the foundations are laid in the research project on a meso scale, we also extended our explorations into an architectural macro scale.For this, we used a more speculative design-build studio that was based on a more loose combination of 3D textiles and 3D printed elements.Lastly, we will discuss, how this first architectural application beneficially informed the research project.

3D printing of novel and smart materials has received considerable attention due to its applications within biological and medical fields, mostly as they can be used to print complex architectures and particular designs. However, the internal structure during 3D printing can be problematic to resolve. We present here how time-resolved synchrotron microbeam Small-Angle X-ray Diffraction (μ-SAXD) allows us to elucidate the local orientational structure of a liquid crystal elastomer-based printed scaffold. Most reported 3D-printed liquid crystal elastomers are mainly nematic; here, we present a Smectic-A 3D-printed liquid crystal elastomer that has previously been reported to promote cell proliferation and alignment. The data obtained on the 3D-printed filaments will provide insights into the internal structure of the liquid crystal elastomer for the future fabrication of liquid crystal elastomers as responsive and anisotropic 3D cell scaffolds.

Novel composite 3D-printed filament made from fish scale-derived hydroxyapatite, eggshell and polylactic acid via a fused fabrication approach

This study aimed to examine an innovative approach for recycling and repurposing used disposable face masks to create a new 3D printing filament and to compare the mechanical properties of the developed 3D printing filament (DF) with recycled filament (RF) and commercial filament (CF). The development of the new 3D printing filaments involved examining three key pieces of information: (1) optimal melting point ranges, (2) weight, and (3) visual colors for each layer of the face mask. Using an experimental research design, the researchers melted-down disposable face masks to create the filament and analyzed its properties in comparison with RF and CF. No significant differences were identified in terms of strength among CF, RF, and DF types. The findings highlight the potential effectiveness of using disposable face masks as an alternative 3D printing material, contributing to the design and production in the 3D printing industry.

Influence of biobased plasticizers on 3D printed polylactic acid composites filled with sustainable biofiller

Particle and volatile organic compound emissions from a 3D printer filament extruder

This experimental study aims to explore the failure behavior of a pre- and post-cracked polymeric 3D printed components subjected to tensile mode. A set of through-thickness pre-cracked specimens of different cracks patterns and geometry was designed and implemented in the 3D printed parts. The specimens are then subjected to a tensile test mode. Besides, analogous intact samples were produced by 3D printing technology where the through-thickness post-cracks were created using laser cutting process of a geometry with cracks similar to those of the pre-cracked specimens. It has been observed that the pre-cracked samples initially introduced, and 3D printed cracked specimens have more resistance to fracture mechanics failure due to crack-bridging caused by the 3D printing filament profile around the crack profile. On the other hand, the samples with post-cracks made by laser cutting demonstrated a significant drop in the fracture failure resistance due to the interruption of the 3D printed filaments of the intact specimens. In conclusion, this study revealed that pre-cracked 3D printed components did not show the actual failure and fracture mechanics behavior. This is because the cracks could be introduced in the components after the additive manufacturing process during the service life and that would damage the 3D printed filament path of the components and, hence, will cause high-stress concentration that leads to unpredicted and fast failure.KeywordsFDMFracture mechanicsCrack3D printing

Industrial Cannabis sativa (hemp or fibre) is mainly used to produce paper, ropes, food, medicines, cosmetics, hempcrete, leather, bioplastic, biochar, 3D printing homes and textiles. Hempcrete is a building construction material made from Industrial hemp fibers, lime and water. Hempcrete is a cost effective and sustainable properties which makes as a promising material in both new projects and those involving renovation. 3D printing, also known as additive manufacturing, is a method of creating a three dimensional object layer-by-layer using a computer created design. The process works by laying down thin layers of material in the form of liquid or powdered plastic, metal or cement, and then fusing the layers together. Hemp has been applied in filaments for 3D printing. Hemp filament is a promising and sustainable alternative to traditional 3D printing materials. The 3D printing industry has been integrating hemp into its technology. Hemp can be transformed into filament to be used for 3D printing. 3D printing is used to apply computer-aided design (CAD) files of 3D objects, which are digitally designed for use in different applications or obtained by scanning an existing object through therapeutic prototyping or rapid manufacturing. The building construction with 3D printing technologies could be a game-changer and Tvasta Manufacturing Solutions, Chennai, with IIT Madras, Tamil Nadu, India has constructed the first 3D printed buildings in India. The efficiency of 3D printing outpaces traditional building times and methods. As the world of 3D printing continues to evolve, hemp filament is emerging as a viable and eco-friendly alternative. Hemp filament shares many printing properties with polylactic acid (PLA), making it easy to use for various 3D printing applications. One of the biotechnology company, Makeinica at Bengaluru, Karnataka, India has developed manufacturing process, and practical applications of hemp filament in 3D printing, with a focus on its potential for 3D printing services in India. Several companies have developed their versions of hemp 3D printer filament, contributing to the growing market for biodegradable and sustainable materials.

Wood fibres are hygroscopic and swell when immersed in water. This effect can be used to create shape-changing structures in 3D printing. Hence, wood fibre reinforced filaments have the potential to be used in four-dimensional (4D) printing. In this work, biocomposites based on granulated or milled thermomechanical pulp (TMP) fibres and poly(lactic acid) (PLA) were prepared and evaluated based on their tensile properties. Poly(hydroxyalkanoates) (PHA) or poly(butylene-adipate-terephthalate) (PBAT) were included in the biocomposite recipes to assess their effect on the melt flow index (MFI) and tensile properties. Clear effects of the TMP fibre morphology on MFI were quantified. Biocomposites containing 20 wt% PBAT turned out to be stronger and tougher than the ones containing PHA. Based on that, filaments for 3D and 4D printing were manufactured. Interestingly, the tensile strength of 3D printed specimens containing milled TMP (TMPm) fibres was about 33% higher compared to those containing TMP fibre granulate (TMPg). Using hot water as the stimulus, the 3D printed specimens containing TMPg showed a greater reactivity and shape change compared to TMPm specimens. • Differences in TMP fibre morphology affect the melt-flow-index of biocomposites. • PBAT elastomer ensures the manufacturing of strong and tough biocomposites with enhanced flow properties for 3D printing. • 3D printed parts with shorter TMP fibre fragments showed greater tensile strength and were less brittle. • Mono- and bi-material 3D printed biocomposite causes shape morphing properties, using water as an external stimulus.

Functionalities of 3D printing filaments have gained much attention owing to their properties for various applications in the last few years. Innovative biocomposite 3D printing filaments based on polylactic acid (PLA) composited with ZnO nanoflowers at varying contents were successfully fabricated via a single-screw extrusion technique. The effects of the varying ZnO nanoflower contents on their chemical, thermal, mechanical, and antibacterial properties were investigated using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and tensile testing, as well as qualitative and quantitative antibacterial tests, respectively. It was found that the ZnO nanoflowers did not express any chemical reactions with the PLA chains. The degrees of the crystallinity of the PLA/ZnO biocomposite filaments increased when compared with those of the neat PLA, and their properties slightly decreased when increasing the ZnO nanoflower contents. Additionally, the tensile strength of the PLA/ZnO biocomposite filaments gradually decreased when increasing the ZnO nanoflower contents. The antibacterial activity especially increased when increasing the ZnO nanoflower contents. Additionally, these 3D printing filaments performed better against Gram-positive (S. aureus) than Gram-negative (E. coli). This is probably due to the difference in the cell walls of the bacterial strains. The results indicated that these 3D printing filaments could be utilized for 3D printing and applied to medical fields.

3D printing has become widely used to rapidly prototype and manufacture novel or bespoke objects or replacement components in a wide range of marine industries, engineering, and research. 3D-printed objects are subject to marine biofouling, impacting their operation and longevity. Application of antifouling paints or coatings adds costly and time-consuming steps and may interfere with the function of fine surface features, counteracting some of the benefits of 3D-printing technology. We measured the antifouling performance of two 3D-printing thermoplastics embedded with antifouling biocides to create 3D-printed materials with inherent antifouling properties: 1) polycaprolactone (PCL) mixed with the organic biocide dichlorooctylisothiazolinone (DCOIT) and extruded as 3D-printing filament, and 2) a commercial polylactic acid (PLA) 3D-printing filament with embedded copper powder. Settlement plates printed from these thermoplastics (“PCL-DCOIT” and “PLA-Cu”, respectively) and deployed in temperate, coastal marine water for 17 weeks during summer remained free of macrofouling. A biofilm developed, and 16S and 18S rRNA metabarcoding analyses revealed that early stage biofilms (at 5 and 12 weeks) had dramatically altered assemblage structures of both prokaryotes and eukaryotes compared to natural biofilms. The assemblage on PCL-DCOIT had reduced microbial diversity, strong dominance of Proteobacteria and chlorophytes, and almost complete absence of Flavobacteriia, Cyanobacteria, and diatoms. In contrast, the biofilm on PLA-Cu had a dominance of Flavobacteriia over Proteobacteria, and resistance to chlorophytes, yet similar to PCL-DCOIT it resisted Cyanobacteria and diatoms. Such alterations to biofilm microbial assemblages could influence microbial dynamics, biofilm growth, and settlement cues to which biofouler propagules respond. At 17 weeks, the two biocide-embedded thermoplastics completely resisted macrofouling, equally well as three commercial antifouling coatings (Intercept 8500, Hempaguard X7, Hempasil X3); however, PCL-DCOIT was more extensively covered by a microalgal film (79%, evidently chlorophytes) than were the commercial coatings, and PLA-Cu had the most settled detritus (100% cover). Biofilm assemblages on the commercial coatings were investigated for comparison, with PCL-DCOIT standing out due to its almost complete resistance to Flavobacteriia. Thermoplastic 3D-printing filaments with embedded biocides show promise for producing 3D-printed objects with inherent antifouling properties, avoiding or lessening the need to apply antifouling coatings, and possibly extending their service lifetime.

Wood flour-poly(lactic acid) 3D printing filaments were prepared via a melt extrusion method. Poplar wood flour and poly(lactic acid) (PLA) were used as raw materials, and different combinations of glycerol and tributyl citrate (TBC) (4% glycerol, 2% glycerol + 2% TBC, 4% TBC) were used as plasticizers. A 3D printer was used to print the filaments into standard test specimens with dimensions of 150 mm × 10 mm × 0.2 mm at the printing temperature of 220 °C. The performance of wood flour-poly(lactic acid) 3D printing filaments in terms of their interfacial compatibility, mechanical properties, melt index (MI), water absorption, and heat stability was tested under different plasticizer combinations. The results showed that under the condition of same dosage of plasticizer, the order of MI for the 3D printed filaments from high to low was 4% glycerol > 2% glycerol + 2% TBC > 4% TBC, which indicated that glycerol was more favorable for the extrusion processing of the composite filaments. However, in terms of compatibility, mechanical properties, water absorption, and thermal stability, the 3D printing filaments with 4% TBC showed better performance compared with other groups.

Fabrication of Montelukast sodium loaded filaments and 3D printing transdermal patches onto packaging material.