scholarly journals Embedding Ultra-High-Molecular-Weight Polyethylene Fibers in 3D-Printed Polylactic Acid (PLA) Parts

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1825 ◽  
Author(s):  
Amza ◽  
Zapciu ◽  
Eyþórsdóttir ◽  
Björnsdóttir ◽  
Borg
Keyword(s):  
Molecular Weight ◽  
Tensile Strength ◽  
3D Printing ◽  
High Molecular Weight ◽  
Polylactic Acid ◽  
Strength Tests ◽  
Raster Angle ◽  
Uhmwpe Fibers ◽  
3D Printed ◽  
Ultra High Molecular Weight

This study aims to assess whether ultra-high-molecular-weight polyethylene (UHMWPE) fibers can be successfully embedded in a polylactic acid (PLA) matrix in a material extrusion 3D printing (ME3DP) process, despite the apparent thermal incompatibility between the two materials. The work started with assessing the maximum PLA extrusion temperatures at which UHMWPE fibers withstand the 3D printing process without melting or severe degradation. After testing various fiber orientations and extrusion temperatures, it has been found that the maximum extrusion temperature depends on fiber orientation relative to extrusion pathing and varies between 175 °C and 185 °C at an ambient temperature of 25 °C. Multiple specimens with embedded strands of UHMWPE fibers have been 3D printed and following tensile strength tests on the fabricated specimens, it has been found that adding even a small number of fiber strands laid in the same direction as the load increased tensile strength by 12% to 23% depending on the raster angle, even when taking into account the decrease in tensile strength due to reduced performance of the PLA substrate caused by lower extrusion temperatures.

scholarly journals Melt- vs. Non-Melt Blending of Complexly Processable Ultra-High Molecular Weight Polyethylene/Cellulose Nanofiber Bionanocomposite

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 404
Author(s):  
Nur Sharmila Sharip ◽  
Hidayah Ariffin ◽  
Tengku Arisyah Tengku Yasim-Anuar ◽  
Yoshito Andou ◽  
Yuki Shirosaki ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Tensile Strength ◽  
Yield Strength ◽  
Young’S Modulus ◽  
High Molecular Weight ◽  
Melt Processing ◽  
Cellulose Nanofiber ◽  
Melt Blending ◽  
Ultra High Molecular Weight

The major hurdle in melt-processing of ultra-high molecular weight polyethylene (UHMWPE) nanocomposite lies on the high melt viscosity of the UHMWPE, which may contribute to poor dispersion and distribution of the nanofiller. In this study, UHMWPE/cellulose nanofiber (UHMWPE/CNF) bionanocomposites were prepared by two different blending methods: (i) melt blending at 150 °C in a triple screw kneading extruder, and (ii) non-melt blending by ethanol mixing at room temperature. Results showed that melt-processing of UHMWPE without CNF (MB-UHMWPE/0) exhibited an increment in yield strength and Young’s modulus by 15% and 25%, respectively, compared to the Neat-UHMWPE. Tensile strength was however reduced by almost half. Ethanol mixed sample without CNF (EM-UHMWPE/0) on the other hand showed slight decrement in all mechanical properties tested. At 0.5% CNF inclusion, the mechanical properties of melt-blended bionanocomposites (MB-UHMWPE/0.5) were improved as compared to Neat-UHMWPE. It was also found that the yield strength, elongation at break, Young’s modulus, toughness and crystallinity of MB-UHMWPE/0.5 were higher by 28%, 61%, 47%, 45% and 11%, respectively, as compared to the ethanol mixing sample (EM-UHMWPE/0.5). Despite the reduction in tensile strength of MB-UHMWPE/0.5, the value i.e., 28.4 ± 1.0 MPa surpassed the minimum requirement of standard specification for fabricated UHMWPE in surgical implant application. Overall, melt-blending processing is more suitable for the preparation of UHMWPE/CNF bionanocomposites as exhibited by their characteristics presented herein. A better mechanical interlocking between UHMWPE and CNF at high temperature mixing with kneading was evident through FE-SEM observation, explains the higher mechanical properties of MB-UHMWPE/0.5 as compared to EM-UHMWPE/0.5.

The effect of simultaneous fiber surface treatment and matrix modification on mechanical properties of unidirectional ultra-high molecular weight polyethylene fiber/epoxy/nanoclay nanocomposites

2018 ◽  
Vol 52 (21) ◽  
pp. 2961-2972 ◽  
Author(s):  
Mohammad Mohammadalipour ◽  
Mahmood Masoomi ◽  
Mojtaba Ahmadi ◽  
Zahra Kazemi
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Tensile Strength ◽  
High Molecular Weight ◽  
Glycidyl Methacrylate ◽  
Interfacial Adhesion ◽  
Fiber Surface ◽  
Cohesive Failure ◽  
Polyethylene Fiber ◽  
Ultra High Molecular Weight

Nonpolar structure of ultra-high molecular weight polyethylene fiber leads to a weak interfacial adhesion in ultra-high molecular weight polyethylene fiber reinforced epoxy composite. Herein, synchronized fiber and matrix modifications were utilized so as to improve the interfacial adhesion, resulting in promoting mechanical properties of these composites. For this purpose, the surface of ultra-high molecular weight polyethylene fiber was chemically treated with glycidyl methacrylate and the epoxy resin was modified through incorporation of different contents of nanoclay. The mechanical properties results showed that individual modification, either fiber or matrix, can just lead to improvements around 36.74% and 10.54% in tensile strength as well as 14.28% and 4.27% in tensile modulus, respectively. However, the ultimate outcome of the study revealed that much higher improvement can be achieved in synergistic attitude. The highest enhancement around 48.31% and 26.76% in tensile strength and modulus were seen for the sample containing glycidyl methacrylate-treated ultra-high molecular weight polyethylene fibers as reinforcement and nano epoxy modified with 1 wt.% of nanoclay. Such observation could be attributed to the mechanical interlocking and chemical reaction which were arising from incorporation of nanoclay in matrix and chemical treatment of fiber surface, correspondingly. In this regard, fiber roughness and chemical bonds formed between treated fiber and modified matrix play a key role in improving interfacial adhesion. Moreover, the fractured surface of such composites studied by scanning electron microscope confirmed the mechanical results and showed that much more matrix was adhered to the fiber surface after treatment, indicating cohesive failure.

scholarly journals Ultra-high molecular weight elastomeric polyethylene using an electronically and sterically enhanced nickel catalyst

2017 ◽  
Vol 8 (41) ◽  
pp. 6416-6430 ◽  
Author(s):  
Qaiser Mahmood ◽  
Yanning Zeng ◽  
Erlin Yue ◽  
Gregory A. Solan ◽  
Tongling Liang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Tensile Strength ◽  
High Molecular Weight ◽  
Nickel Catalyst ◽  
High Tensile Strength ◽  
Elongation At Break ◽  
Highly Active ◽  
High Elongation ◽  
Ultra High Molecular Weight ◽  
Shape Fixity

Highly active para-t-Bu-containing 1,2-bis(imino)acenaphthene-Ni(ii) catalysts are disclosed which afford hyper-branched PEs with Mw's up to 3.1 × 106 g mol−1; high tensile strength, excellent shape fixity as well as high elongation at break are a feature.

scholarly journals Development and Characterization of a 3D Printed Cocoa Bean Shell Filled Recycled Polypropylene for Sustainable Composites

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3162
Author(s):  
Maria A. Morales ◽  
Alejandro Maranon ◽  
Camilo Hernandez ◽  
Alicia Porras
Keyword(s):  
Tensile Strength ◽  
3D Printing ◽  
Failure Mechanisms ◽  
Industrial Wastes ◽  
Cocoa Bean ◽  
Recycled Polypropylene ◽  
Raster Angle ◽  
3D Printed ◽  
Natural Filler

Natural filler-based composites are an environmentally friendly and potentially sustainable alternative to synthetic or plastic counterparts. Recycling polymers and using agro-industrial wastes are measures that help to achieve a circular economy. Thus, this work presents the development and characterization of a 3D printing filament based on recycled polypropylene and cocoa bean shells, which has not been explored yet. The obtained composites were thermally and physically characterized. In addition, the warping effect, mechanical, and morphological analyses were performed on 3D printed specimens. Thermal analysis exhibited decreased thermal stability when cacao bean shell (CBS) particles were added due to their lignocellulosic content. A reduction in both melting enthalpy and crystallinity percentage was identified. This is caused by the increase in the amorphous structures present in the hemicellulose and lignin of the CBS. Mechanical tests showed high dependence of the mechanical properties on the 3D printing raster angle. Tensile strength increased when a raster angle of 0° was used, compared to specimens printed at 90°, due to the load direction. Tensile strength and fracture strain were improved with CBS addition in specimens printed at 90°, and better bonding between adjacent layers was achieved. Electron microscope images identified particle fracture, filler-matrix debonding, and matrix breakage as the central failure mechanisms. These failure mechanisms are attributed to the poor interfacial bonding between the CBS particles and the matrix, which reduced the tensile properties of specimens printed at 0°. On the other hand, the printing process showed that cocoa bean shell particles reduced by 67% the characteristic warping effect of recycled polypropylene during 3D printing, which is advantageous for 3D printing applications of the rPP. Thereby, potential sustainable natural filler composite filaments for 3D printing applications with low density and low cost can be developed, adding value to agro-industrial and plastic wastes.

Ultra-high molecular weight polyethylene fiber-reinforced thermoplastic corn starch composite

2016 ◽  
Vol 30 (4) ◽  
pp. 564-577 ◽  
Author(s):  
Bin Guo ◽  
Li-Jian Wang ◽  
Peng Yin ◽  
Ben-Gang Li ◽  
Pan-Xin Li
Keyword(s):  
Molecular Weight ◽  
Contact Angle ◽  
High Molecular Weight ◽  
Corn Starch ◽  
Thermoplastic Starch ◽  
Polyethylene Fiber ◽  
Twin Screw ◽  
Uhmwpe Fibers ◽  
Fibrous Morphology ◽  
Ultra High Molecular Weight

The ultra-high molecular weight polyethylene (UHMWPE) fibers, as the fibrous morphology of polyethylene (PE), were first used to reinforce thermoplastic starch (TPS) by a twin screw extruder. The influence of the UHMWPE content on the mechanical and dynamic mechanical thermal properties, thermal stability, contact angle, torque rheological properties, and fractured surface morphology of the UHMWPE/TPS composites was studied in detail. We found that the UHMWPE fibers were well dispersed in the TPS matrix, and the mechanical properties and water resistance of the composites improved significantly. Especially, the incorporation of UHMWPE fibers at a content of 2 wt% generated a composite with better performance (tensile strength of 8.78 MPa and contact angle of 80.2°).

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