Research

14 pages, 10725 KiB

Open AccessArticle

Additive Manufacturing of Carbon Fiber Reinforced Epoxy Thermoset with Improved Thermomechanical Properties

by Md Sahid Hassan, Antonio Delgadillo, Md Shahjahan Mahmud, Joseph Munoz, Saqlain Zaman, Sofia Gabriela Gomez, Cory Marquez, Johnny C. Ho and Yirong Lin

J. Compos. Sci. 2023, 7(4), 171; https://0-doi-org.brum.beds.ac.uk/10.3390/jcs7040171 - 20 Apr 2023

Cited by 1 | Viewed by 1357

Abstract

Laser Powder Bed Fusion (LPBF) is a widely used additive manufacturing technique for powder-based polymers and metallic materials. Thermoplastics like Polyamide 12 and Polyamide 6 are commonly used in LPBF; thermosetting polymers are gaining attention due to their superior stability. Epoxies are a [...] Read more.

Laser Powder Bed Fusion (LPBF) is a widely used additive manufacturing technique for powder-based polymers and metallic materials. Thermoplastics like Polyamide 12 and Polyamide 6 are commonly used in LPBF; thermosetting polymers are gaining attention due to their superior stability. Epoxies are a popular thermoset, but some exhibit low physical properties and brittleness, leading to reduced toughness. The work presented in this paper explores the effect of using short carbon fibers (CF) as additives to epoxy-based thermosetting material on physical and thermomechanical properties. A total of six epoxy thermoset/CF composite powder blends were prepared by varying reinforcing materials weight percentages (0 wt%, 0.3 wt%, 0.6 wt%, 1 wt%, 5 wt%, and 10 wt%). Tensile, four-point bending, and dynamic mechanical analysis (DMA) test samples were printed using the LPBF technique. Significant improvements in the physical and thermomechanical properties were obtained in the thermoset composites with 5 wt% of CF due to good adhesion between reinforcing materials and the matrix and a low level of porosity. Fracture surface analysis was performed via scanning electron microscopy (SEM), which provided insight into the influence of CF on the properties of thermosetting composites. The findings of this research demonstrate the feasibility of improving the inferior physical and thermomechanical properties of 3D-printed CF-reinforced epoxy. With a certain amount of CF reinforcement, Young’s modulus and fracture modulus can be increased by around 52% and 259%, respectively. Full article

(This article belongs to the Special Issue Additive Manufacturing of Composites and Nanocomposites)

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12 pages, 2186 KiB

Open AccessArticle

Implementation of Antibacterial Nanoparticles in Additive Manufacturing to Increase Part Strength and Stiffness

by Christopher Billings, Peter Kim, Tyler Shadid, Jimmy D. Ballard, Changjie Cai and Yingtao Liu

J. Compos. Sci. 2022, 6(9), 248; https://0-doi-org.brum.beds.ac.uk/10.3390/jcs6090248 - 25 Aug 2022

Cited by 1 | Viewed by 1259

Abstract

The introduction of novel composites suited for additive manufacturing machines offers a solution for the current slow adoption of the technology. Many composites offer secondary functions and mechanical improvements to suit unique applications better. This article presents the creation of a set of [...] Read more.

The introduction of novel composites suited for additive manufacturing machines offers a solution for the current slow adoption of the technology. Many composites offer secondary functions and mechanical improvements to suit unique applications better. This article presents the creation of a set of novel nanocomposites consisting of zinc oxide (ZnO) and a photocurable resin using a masked stereolithography additive machine. These nanocomposites are produced in 1%, 2.5%, 5%, and 7.5% concentrations and are characterized based on their mechanical and surface properties. Using ZnO allows for the creation of mechanically stronger parts with reduced wettability while offering antibacterial properties throughout the entire part. Best results were observed at a 5% concentration of ZnO with a nearly 25% strength increase and 45% decrease in wettability. Additionally, SEM analysis demonstrated proper dispersion with minimal agglomerations present. In the sporicidal effect analysis, the ZnO (with 7.5% concentration) reduced 31.5% of Clostridioides difficile spores. These results demonstrate the capability of producing antibacterial nanocomposites using low-cost additive manufacturing to enhance public health options. Full article

(This article belongs to the Special Issue Additive Manufacturing of Composites and Nanocomposites)

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12 pages, 11825 KiB

Open AccessArticle

Mechanical Properties of High-Temperature Fiber-Reinforced Thermoset Composites with Plain Weave and Unidirectional Carbon Fiber Fillers

by Samuel Ernesto Hall, Victoria Centeno, Sergio Favela, Alexis Lopez, Andrew Gallardo, Jacob Pellicotte, Yulianna Torres, Danielle Coverdell, Sabrina Torres, Ahsan Choudhuri, Yirong Lin and Md Sahid Hassan

J. Compos. Sci. 2022, 6(7), 213; https://0-doi-org.brum.beds.ac.uk/10.3390/jcs6070213 - 18 Jul 2022

Cited by 2 | Viewed by 1760

Abstract

Fiber-reinforced thermoset composites are a class of materials that address the arising needs from the aerospace and hypersonic industries for high specific strength, temperature-resistant structural materials. Among the high-temperature resistant thermoset categories, phenolic triazine (PT) cyanate esters stand out thanks to their inherent [...] Read more.

Fiber-reinforced thermoset composites are a class of materials that address the arising needs from the aerospace and hypersonic industries for high specific strength, temperature-resistant structural materials. Among the high-temperature resistant thermoset categories, phenolic triazine (PT) cyanate esters stand out thanks to their inherent high degradation temperature, glass transition temperature, and mechanical strength. Despite the outstanding properties of these thermosets, the performance of carbon fiber composites using PT cyanate esters as matrices has not been thoroughly characterized. This work evaluated PT and carbon fiber composites’ compressive properties and failure mechanisms with different fiber arrangements. A PT resin with both plain weave (PW) and non-crimped unidirectional (UD) carbon fiber mats was analyzed in this research. Highly loaded thermoset composites were obtained using process temperatures not exceeding 260 °C, and the composites proved to retain compressive strength at temperatures beyond 300 °C. Compressive testing revealed that PT composites retained compressive strength values of 50.4% of room temperature for UD composites and 61.4% for PW composites. Post-compressive failure observations of the gage section revealed that the mechanisms for failure evolved with temperature from brittle, delamination-dominant failure to shear-like failure promoted by the plastic failure of the matrix. This study demonstrated that PT composites are a good candidate for structural applications in harsh environments. Full article

(This article belongs to the Special Issue Additive Manufacturing of Composites and Nanocomposites)

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10 pages, 2666 KiB

Open AccessArticle

Optimization of Chitin Nanofiber Preparation by Ball Milling as Filler for Composite Resin

by Dagmawi Abebe Zewude, Hironori Izawa and Shinsuke Ifuku

J. Compos. Sci. 2022, 6(7), 197; https://0-doi-org.brum.beds.ac.uk/10.3390/jcs6070197 - 06 Jul 2022

Cited by 1 | Viewed by 1554

Abstract

Chitin nanofiber is a nanomaterial produced by pulverizing chitin, the main component of crab shells. Since it has excellent mechanical properties, it is expected to be used as a reinforcing material to strengthen materials. Chitin was mechanically ground in water using a ball [...] Read more.

Chitin nanofiber is a nanomaterial produced by pulverizing chitin, the main component of crab shells. Since it has excellent mechanical properties, it is expected to be used as a reinforcing material to strengthen materials. Chitin was mechanically ground in water using a ball mill to prepare nanofibers. The ball size, total ball weight, and milling time were varied, and the resulting water dispersion and the cast film were analyzed to optimize the conditions for efficient preparation. The length and width of the nanofibers were also measured by SEM and AFM observations. The size of the balls affected the level of grinding and the intensity of impact energy on the chitin. The most efficient crushing was achieved when the diameter was 1 mm. The total ball weight directly affects the milling frequency, and milling proceeds as the total weight increases. However, if too many balls occupy the container, the grinding efficiency decreases. Therefore, a total ball weight of 300 g was optimal. Regarding the milling time, the chitin becomes finer depending on the increase of that time. However, after a specific time, the shape did not change much. Therefore, a milling time of approximately 150 min was appropriate. Full article

(This article belongs to the Special Issue Additive Manufacturing of Composites and Nanocomposites)

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11 pages, 3827 KiB

Open AccessArticle

Flame-Retardant and Tensile Properties of Polyamide 12 Processed by Selective Laser Sintering

by Tatjana Glaskova-Kuzmina, Didzis Dejus, Jānis Jātnieks, Partel-Peeter Kruuv, Linda Lancere, Stepans Kobenko, Anatolijs Sarakovskis and Aleksejs Zolotarjovs

J. Compos. Sci. 2022, 6(7), 185; https://0-doi-org.brum.beds.ac.uk/10.3390/jcs6070185 - 23 Jun 2022

Cited by 5 | Viewed by 1407

Abstract

Composite materials are becoming widely applied in fire-critical conditions such as, e.g., aviation interior parts. Environmental considerations motivate the use of additive manufacturing due to the decrease of polymer wastes, and therefore additional fuel sources. The aim of this work was to evaluate [...] Read more.

Composite materials are becoming widely applied in fire-critical conditions such as, e.g., aviation interior parts. Environmental considerations motivate the use of additive manufacturing due to the decrease of polymer wastes, and therefore additional fuel sources. The aim of this work was to evaluate the effect of printing direction on flame retardancy and the tensile properties of 3D-printed test samples of polyamide 12 manufactured by selective laser sintering. The effects of printing parameters on the flammability of 3D-printed samples were investigated using vertical burn tests with varied specimen thicknesses and printing directions. It was found that these effects were substantial for the flammability at a low thickness of the test samples. No significant effects of printing direction were revealed for the tensile characteristics of polyamide 12. Full article

(This article belongs to the Special Issue Additive Manufacturing of Composites and Nanocomposites)

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9 pages, 35623 KiB

Open AccessArticle

Effect of WS₂ Nanotubes on the Mechanical and Wear Behaviors of AZ31 Stir Casted Magnesium Metal Matrix Composites

by Murugan Subramani, Song-Jeng Huang and Konstantin Borodianskiy

J. Compos. Sci. 2022, 6(7), 182; https://0-doi-org.brum.beds.ac.uk/10.3390/jcs6070182 - 21 Jun 2022

Cited by 5 | Viewed by 1688

Abstract

In this study, the AZ31 magnesium alloy was reinforced with tungsten disulfide (WS₂) nanotubes to fabricate the nanocomposite using the stir casting method. The microstructural analysis, mechanical and wear behaviors were investigated with the effect of WS₂ on the AZ31 [...] Read more.

In this study, the AZ31 magnesium alloy was reinforced with tungsten disulfide (WS₂) nanotubes to fabricate the nanocomposite using the stir casting method. The microstructural analysis, mechanical and wear behaviors were investigated with the effect of WS₂ on the AZ31 alloy. Scanning electron microscopy (SEM) was used to conduct the microstructural analysis. The microstructures are revealed to incorporate the aluminum content with the WS₂ nanotube, disclose the presence of the secondary phase, which was increased compared with the AZ31 alloy and was detected by energy dispersive spectroscopy (EDS). The mechanical properties of hardness and yield strength (YS) were significantly improved with the addition of WS₂ nanotubes. This is mainly due to the strengthening mechanisms of Orowan, the coefficient of thermal expansion (CTE) mismatch and the load transfer mechanism. The theoretical YS was calculated and compared with the experimental results. However, the ultimate tensile strength (UTS) and the fracture strain were decreased with the addition of reinforcement which might be owing to the clustering of nanotubes. Finally, the wear behavior of the wear weight loss and depth of cut was investigated. This test revealed that the addition of WS₂ nanotubes reduced the weight loss and depth of the material cutting that was mainly due to the presence of hard WS₂ nanotubes. Full article

(This article belongs to the Special Issue Additive Manufacturing of Composites and Nanocomposites)

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8 pages, 6318 KiB

Open AccessArticle

Nanostructuration Impact on the Basic Properties of the Materials: Novel Composite Carbon Nanotubes on a Copper Surface

by Natalia Kamanina, Andrei Toikka and Dmitry Kvashnin

J. Compos. Sci. 2022, 6(6), 181; https://0-doi-org.brum.beds.ac.uk/10.3390/jcs6060181 - 20 Jun 2022

Cited by 4 | Viewed by 1488

Abstract

Copper is important material that is widely applicable in the electric and electronic industries. Nevertheless, in some circumstances, it is highly desirable to improve its properties. Therefore, combination of materials of various composition and properties attracts scientific and industrial society. Here, the composite [...] Read more.

Copper is important material that is widely applicable in the electric and electronic industries. Nevertheless, in some circumstances, it is highly desirable to improve its properties. Therefore, combination of materials of various composition and properties attracts scientific and industrial society. Here, the composite based on carbon nanotubes (CNTs) on a Cu surface was fabricated using laser-oriented deposition (LOD) technique and studied. Examination of the novel composite showed that its reflectance was decreased, the microhardness was increased, and wetting of the surface exhibited higher hydrophobicity. A molecular dynamic simulation showed that the penetration depth increases with nanotube diameter decrease and growth of the acceleration rate. Topography observations made via AFM images revealed a dense thin film with an almost-homogeneous distribution of CNTs, with several locations with irregular thickness addressing the different lengths of CNTs. Full article

(This article belongs to the Special Issue Additive Manufacturing of Composites and Nanocomposites)

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9 pages, 1775 KiB

Open AccessArticle

Void Content Reduction in 3D Printed Glass Fiber-Reinforced Polymer Composites through Temperature and Pressure Consolidation

by Dakota R. Hetrick, Seyed Hamid Reza Sanei and Omar Ashour

J. Compos. Sci. 2022, 6(5), 128; https://0-doi-org.brum.beds.ac.uk/10.3390/jcs6050128 - 28 Apr 2022

Cited by 4 | Viewed by 2254

Abstract

To improve the properties of additively manufactured parts to be used in high-end applications, intrinsic defects occurring during the printing process need to be minimized. Defects such as void can significantly degrade the mechanical properties of the resulted parts. The presence of void [...] Read more.

To improve the properties of additively manufactured parts to be used in high-end applications, intrinsic defects occurring during the printing process need to be minimized. Defects such as void can significantly degrade the mechanical properties of the resulted parts. The presence of void is more evident in composite printed parts due to the inhomogeneity of the specimen. In this study, composite rectangular coupons printed with a Markforged Mark Two printer were manufactured with different fiber orientations and stacking sequences. A void content reduction/consolidation process, consisting of applying pressure at different temperature levels, was developed and implemented to remove the voids in form of air bubbles trapped in the specimen. A two-part mold with female and male components with the same dimensions as the rectangular specimen was designed and machined to be used in a hot press process. The success of the approach was evaluated by calculating the density of the specimen pre- and post-consolidation. The void content reduction results were highly dependent on fiber orientation; however, the density increased for all tested specimens, confirming the reduction in porosity. Full article

(This article belongs to the Special Issue Additive Manufacturing of Composites and Nanocomposites)

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19 pages, 9886 KiB

Open AccessArticle

Selective Laser Sintering of High-Temperature Thermoset Polymer

by Md Sahid Hassan, Kazi Md Masum Billah, Samuel Ernesto Hall, Sergio Sepulveda, Jaime Eduardo Regis, Cory Marquez, Sergio Cordova, Jasmine Whitaker, Thomas Robison, James Keating, Evgeny Shafirovich and Yirong Lin

J. Compos. Sci. 2022, 6(2), 41; https://0-doi-org.brum.beds.ac.uk/10.3390/jcs6020041 - 24 Jan 2022

Cited by 12 | Viewed by 3602

Abstract

Thermoplastic materials such as PA12 and PA6 have been extensively employed in Selective Laser Sintering (SLS) 3D printing applications due to their printability, processability, and crystalline structure. However, thermoplastic-based materials lack polymer inter-chain bonding, resulting in inferior mechanical and thermal properties and relatively [...] Read more.

Thermoplastic materials such as PA12 and PA6 have been extensively employed in Selective Laser Sintering (SLS) 3D printing applications due to their printability, processability, and crystalline structure. However, thermoplastic-based materials lack polymer inter-chain bonding, resulting in inferior mechanical and thermal properties and relatively low fatigue behavior. Therefore, 3D printing of high-performance crosslinked thermosets using SLS technology is paramount to pursue as an alternative to thermoplastics. In this work, a thermoset resin was successfully 3D printed using SLS, and its thermal stability of printed parts after a multi-step post-curing process was investigated. Dimensionally stable and high glass transition temperature (T_g: ~300 °C) thermoset parts were fabricated using SLS. The polymer crosslinking mechanism during the printing and curing process was investigated through FTIR spectra, while the mechanical stability of the SLS 3D-printed thermoset was characterized through compression tests. It is found that 100% crosslinked thermoset can be 3D printed with 900% higher compressive strength than printed green parts. Full article

(This article belongs to the Special Issue Additive Manufacturing of Composites and Nanocomposites)

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