scholarly journals Evaluation of the Compatibility of Organosolv Lignin-Graphene Nanoplatelets with Photo-Curable Polyurethane in Stereolithography 3D Printing

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1544 ◽  
Author(s):  
Fathirrahman Ibrahim ◽  
Denesh Mohan ◽  
Mohd Shaiful Sajab ◽  
Saiful Bahari Bakarudin ◽  
Hatika Kaco

In this study, lignin has been extracted from oil palm empty fruit bunch (EFB) fibers via an organosolv process. The organosolv lignin obtained was defined by the presence of hydroxyl-containing molecules, such as guaiacyl and syringyl, and by the presence of phenolic molecules in lignin. Subsequently, the extracted organosolv lignin and graphene nanoplatelets (GNP) were utilized as filler and reinforcement in photo-curable polyurethane (PU), which is used in stereolithography 3D printing. The compatibility as well as the characteristic and structural changes of the composite were identified through the mechanical properties of the 3D-printed composites. Furthermore, the tensile strength of the composited lignin and graphene shows significant improvement as high as 27%. The hardness of the photo-curable PU composites measured by nanoindentation exhibited an enormous improvement for 0.6% of lignin-graphene at 92.49 MPa with 238% increment when compared with unmodified PU.

2020 ◽  
Vol 305 ◽  
pp. 28-35
Author(s):  
Anslem Wong Tsu An ◽  
Sujan Debnath ◽  
Vincent Lee Chieng Chen ◽  
Moola Mohan Reddy ◽  
Alokesh Pramanik

In recent years, studies regarding natural fiber reinforced composites have been increased as they are biodegradable with good mechanical performance therefore can help to overcome the environmental issue. As the natural fibers are easy to obtain, many industries have started to make use of natural fiber composites which are light in weight and possess good mechanical properties. However, the natural fiber composites also possess certain limitations most importantly their high moisture absorption ability which makes them incompatible at degradable environment. The fiber constituents of natural fiber composite may have different type of interactions at different environmental conditions. In addition, the involvement of nanoparticles in the composite may be the solution to overcome the deficiencies. In this research, the degradation behaviour of Oil palm empty fruit bunch (OPEFB) fibers reinforced epoxy composites upon exposure to degradable environmental conditions and the effect of adding nanoparticles have been studied. The tensile tests were conducted before and after the exposure to different environmental conditions including plain water, moist soil, brine solution, and cooking oil. Results shows that the addition of 10wt% of OPEFB fiber to the epoxy composites had improved the mechanical tensile strength up to 15.97% and composites exposed to brine solution have the most prominent sign of degradation in mechanical properties in both composites with and without nanosilica. Nevertheless, the composites with nanosilica have shown up to 24.28% improvement in tensile strength after exposure to different environmental conditions. The improvement were attributed due to filling the voids of the composites with nanosilica and good interfacial adhesion between the nanofiller, fiber, and matrix.


2021 ◽  
Vol 1208 (1) ◽  
pp. 012019
Author(s):  
Adi Pandzic ◽  
Damir Hodzic

Abstract One of the advantages provided by fused deposition modelling (FDM) 3D printing technology is the manufacturing of product materials with infill structure, which provides advantages such as reduced production time, product weight and even the final price. In this paper, the tensile mechanical properties, tensile strength and elastic modulus, of PLA, Tough PLA and PC FDM 3D printed materials with the infill structure were analysed and compared. Also, the influence of infill pattern on tensile properties was analysed. Material testing were performed according to ISO 527-2 standard. All results are statistically analysed and results showed that infill pattern have influence on tensile mechanical properties for all three materials.


BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 5012-5031
Author(s):  
Nurul Husna Mohd Hassan ◽  
Noorshashillawati Azura Mohammad ◽  
Mazlan Ibrahim ◽  
Nor Yuziah Mohd Yunus ◽  
Siti Noorbaini Sarmin

The influence of soda-anthraquinone (AQ) pulping conditions on paper properties of oil palm empty fruit bunches was studied using Response Surface Methodology (RSM) based on Central Composite Design (CCD). The alkali charge, NaOH (A), pulping temperature (T), and pulping time (t) ranged between 20 and 30%, 160 and 180 °C, and 60 and 120 minutes, respectively. The mechanical properties evaluated for the handsheets produced were the tensile index, tearing index, bursting index, folding endurance, zero-span tensile strength, and the optical properties (brightness and opacity). The effects of soda-AQ pulping conditions on oil palm empty fruit bunch paper were elucidated by the regression models obtained. The optimum pulping condition were at 27.3% alkali charge, 160 °C, and 60 min that produced paper properties with 26.8 N.m/g tensile index, 7.95 mN.m2/g tearing index, 5.32 kPa.m2/g bursting index, 1.70 log10 folding endurance, 46.2 N zero-span tensile strength, 51.8% brightness, and 95.8% opacity.


Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4132
Author(s):  
Catalin Gheorghe Amza ◽  
Aurelian Zapciu ◽  
Florin Baciu ◽  
Mihai Ion Vasile ◽  
Adrian Ionut Nicoara

In outdoor environments, the action of the Sun through its ultraviolet radiation has a degrading effect on most materials, with polymers being among those affected. In the past few years, 3D printing has seen an increased usage in fabricating parts for functional applications, including parts destined for outdoor use. This paper analyzes the effect of accelerated aging through prolonged exposure to UV-B on the mechanical properties of parts 3D printed from the commonly used polymers polylactic acid (PLA) and polyethylene terephthalate–glycol (PETG). Samples 3D printed from these materials went through a dry 24 h UV-B exposure aging treatment and were then tested against a control group for changes in mechanical properties. Both the tensile and compressive strengths were determined, as well as changes in material creep characteristics. After irradiation, PLA and PETG parts saw significant decreases in both tensile strength (PLA: −5.3%; PETG: −36%) and compression strength (PLA: −6.3%; PETG: −38.3%). Part stiffness did not change significantly following the UV-B exposure and creep behavior was closely connected to the decrease in mechanical properties. A scanning electron microscopy (SEM) fractographic analysis was carried out to better understand the failure mechanism and material structural changes in tensile loaded, accelerated aged parts.


Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1726 ◽  
Author(s):  
Denesh Mohan ◽  
Mohd Shaiful Sajab ◽  
Hatika Kaco ◽  
Saiful Bahari Bakarudin ◽  
An’amt Mohamed Noor

The recognition of nanocellulose has been prominent in recent years as prospect materials, yet the ineffectiveness of nanocellulose to disperse in an organic solvent has restricted its utilization, especially as a reinforcement in polymer nanocomposite. In this study, cellulose has been isolated and defibrillated as cellulose nanofibrils (CNF) from oil palm empty fruit bunch (EFB) fibers. Subsequently, to enhance its compatibility with UV-curable polyurethane (PU)-based resin, the surface hydrophilicity of CNF has been tailored with polyethylene glycol (PEG), as well as reduced graphene oxide (rGO). The dispersibility of reinforced modified CNF in UV-curable PU was examined through the transmittance interruption of resin, chemical, and mechanical properties of the composite printed using the stereolithographic technique. Evidently, the enhanced compatibility of modified CNF and UV-curable PU was shown to improve the tensile strength and hardness of the composites by 37% and 129%, respectively.


2021 ◽  
Vol 1025 ◽  
pp. 47-52
Author(s):  
Denesh Mohan ◽  
Mohd Shaiful Sajab ◽  
Saiful Bahari Bakarudin ◽  
Rasidi Bin Roslan ◽  
Hatika Kaco

3D printing allows industries to scale the development from rapid prototyping to mass production in an easier manner. However, a typical photopolymers resin for stereolithography 3D printing possesses lower mechanical properties which incapable to meet certain industrial requirements for high impact applications. Hence, 0.1 to 2.0 wt.% of graphene nanoplatelets (GnP) were incorporated into photo-curable polyurethane (PU) based resin through digital light processing (DLP) 3D printing to evaluate its reinforcement effect. FTIR spectrum proves that significant characteristics of PU were still dominant upon the addition of GnP, indicating there was no chemical interaction between PU and GnP. The interfacial adhesion and the homogeneity of GnP in PU matrix were investigated through morphological analysis and the strength and stiffness of the 3D-printed composites. Results shows, tensile strength and Young’s Modulus of the PU/1%GnP composite had an increment of 21% and 24%, respectively when compared to neat PU resin. However, further increment of GnP reduced the mechanical properties because of interruption in UV curing during printing, hence leading to interfacial voids and defects on the printed specimens.


Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 562
Author(s):  
Catalin Gheorghe Amza ◽  
Aurelian Zapciu ◽  
George Constantin ◽  
Florin Baciu ◽  
Mihai Ion Vasile

Parts made from thermoplastic polymers fabricated through 3D printing have reduced mechanical properties compared to those fabricated through injection molding. This paper analyzes a post-processing heat treatment aimed at enhancing mechanical properties of 3D printed parts, in order to reduce the difference mentioned above and thus increase their applicability in functional applications. Polyethylene Terephthalate Glycol (PETG) polymer is used to 3D print test parts with 100% infill. After printing, samples are packed in sodium chloride powder and then heat treated at a temperature of 220 °C for 5 to 15 min. During heat treatment, the powder acts as support, preventing deformation of the parts. Results of destructive testing experiments show a significant increase in tensile and compressive strength following heat treatment. Treated parts 3D printed in vertical orientation, usually the weakest, display 143% higher tensile strength compared to a control group, surpassing the tensile strength of untreated parts printed in horizontal orientation—usually the strongest. Furthermore, compressive strength increases by 50% following heat treatment compared to control group. SEM analysis reveals improved internal structure after heat treatment. These results show that the investigated heat treatment increases mechanical characteristics of 3D printed PETG parts, without the downside of severe part deformation, thus reducing the performance gap between 3D printing and injection molding when using common polymers.


Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 545
Author(s):  
Krzysztof Rodzeń ◽  
Preetam K. Sharma ◽  
Alistair McIlhagger ◽  
Mozaffar Mokhtari ◽  
Foram Dave ◽  
...  

The manufacture of polyetheretherketone/hydroxyapatite (PEEK/HA) composites is seen as a viable approach to help enhance direct bone apposition in orthopaedic implants. A range of methods have been used to produce composites, including Selective Laser Sintering and injection moulding. Such techniques have drawbacks and lack flexibility to manufacture complex, custom-designed implants. 3D printing gets around many of the restraints and provides new opportunities for innovative solutions that are structurally suited to meet the needs of the patient. This work reports the direct 3D printing of extruded PEEK/HA composite filaments via a Fused Filament Fabrication (FFF) approach. In this work samples are 3D printed by a custom modified commercial printer Ultimaker 2+ (UM2+). SEM-EDX and µCT analyses show that HA particles are evenly distributed throughout the bulk and across the surface of the native 3D printed samples, with XRD highlighting up to 50% crystallinity and crystalline domains clearly observed in SEM and HR-TEM analyses. This highlights the favourable temperature conditions during 3D printing. The yield stress and ultimate tensile strength obtained for all the samples are comparable to human femoral cortical bone. The results show how FFF 3D printing of PEEK/HA composites up to 30 wt% HA can be achieved.


Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5042
Author(s):  
Jaeyoung Kwon ◽  
Junhyeok Ock ◽  
Namkug Kim

3D printing technology has been extensively applied in the medical field, but the ability to replicate tissues that experience significant loads and undergo substantial deformation, such as the aorta, remains elusive. Therefore, this study proposed a method to imitate the mechanical characteristics of the aortic wall by 3D printing embedded patterns and combining two materials with different physical properties. First, we determined the mechanical properties of the selected base materials (Agilus and Dragonskin 30) and pattern materials (VeroCyan and TPU 95A) and performed tensile testing. Three patterns were designed and embedded in printed Agilus–VeroCyan and Dragonskin 30–TPU 95A specimens. Tensile tests were then performed on the printed specimens, and the stress-strain curves were evaluated. The samples with one of the two tested orthotropic patterns exceeded the tensile strength and strain properties of a human aorta. Specifically, a tensile strength of 2.15 ± 0.15 MPa and strain at breaking of 3.18 ± 0.05 mm/mm were measured in the study; the human aorta is considered to have tensile strength and strain at breaking of 2.0–3.0 MPa and 2.0–2.3 mm/mm, respectively. These findings indicate the potential for developing more representative aortic phantoms based on the approach in this study.


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