polyamide 11
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2022 ◽  
Vol 14 (2) ◽  
pp. 877
Author(s):  
Ellen Fernandez ◽  
Mariya Edeleva ◽  
Rudinei Fiorio ◽  
Ludwig Cardon ◽  
Dagmar R. D’hooge

To reduce plastic waste generation from failed product batches during industrial injection molding, the sustainable production of representative prototypes is essential. Interesting is the more recent hybrid injection molding (HM) technique, in which a polymeric mold core and cavity are produced via additive manufacturing (AM) and are both placed in an overall metal housing for the final polymeric part production. HM requires less material waste and energy compared to conventional subtractive injection molding, at least if its process parameters are properly tuned. In the present work, several options of AM insert production are compared with full metal/steel mold inserts, selecting isotactic polypropylene as the injected polymer. These options are defined by both the AM method and the material considered and are evaluated with respect to the insert mechanical and conductive properties, also considering Moldex3D simulations. These simulations are conducted with inputted measured temperature-dependent AM material properties to identify in silico indicators for wear and to perform cooling cycle time minimization. It is shown that PolyJetted Digital acrylonitrile-butadiene-styrene (ABS) polymer and Multi jet fusioned (MJF) polyamide 11 (PA11) are the most promising. The former option has the best durability for thinner injection molded parts, and the latter option the best cooling cycle times at any thickness, highlighting the need to further develop AM options.


Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 299
Author(s):  
Louise Lods ◽  
Tutea Richmond ◽  
Jany Dandurand ◽  
Eric Dantras ◽  
Colette Lacabanne ◽  
...  

A biobased composite was generated from bamboo fibers (BF) and a polyamide 11 (PA11) matrix. In order to fulfill security requirements, a PA11 already containing a flame retardant (FR) was chosen: This matrix is referred as PA11-FR. In this work, the effects of flame retardant (melamine cyanurate) on the composite properties were considered. In the calorimetric study, the glass transition and melting temperatures of PA11-FR were the same as those of PA11. The melamine cyanurate (MC) had no influence on these parameters. Thermogravimetric analysis revealed that PA11-FR was less stable than PA11. The presence of MC facilitated thermal decomposition regardless of the analysis atmosphere used. It is important to note that the presence of FR did not influence processing conditions (especially the viscosity parameter) for the biosourced composite. Continuous BF-reinforced PA 11-FR composites, single ply, with 60% of fibers were processed and analyzed using dynamic mechanical analysis. In shear mode, comparative data recorded for BF/PA11-FR composite and the PA11-FR matrix demonstrated that the shear glassy modulus was significantly improved: multiplied by a factor of 1.6 due to the presence of fibers. This result reflected hydrogen bonding between reinforcing fibers and the matrix, resulting in a significant transfer of stress. In tensile mode, the conservative modulus of BF/PA11-FR reached E’ = 8.91 GPa. Upon BF introduction, the matrix tensile modulus was multiplied by 5.7. It can be compared with values of a single bamboo fiber recorded under the same experimental conditions: 31.58 GPa. The difference is partly explained by the elementary fibers’ lack of alignment in the composite.


Machines ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 49
Author(s):  
Damian Dzienniak

This paper describes a surface-roughness study performed on samples manufactured additively using the Multi Jet Fusion (MJF) technology. The samples were divided into three groups based on the material used in the process: polypropylene (PP), thermoplastic polyurethane (TPU), and polyamide 11 (PA11). Subsequently, they were tested by means of a roughness-measuring system, which made it possible to determine the typical surface roughness parameters (Ra, Rq, Rz). The tests were designed to examine whether the placement and orientation of 3D objects while printing, in connection with the material used, can significantly influence the surface quality of MJF-printed objects. The results show that the TPU samples have a surface roughness much higher than the PP and PA11 ones, which exhibit roughness levels very similar to each other. It can also be concluded that surfaces printed vertically (along the Z-axis) tend to be less smooth—similarly to the surfaces of objects made of TPU located in the central zones of the print chamber during printing. This information may be of value in cases where low surface roughness is preferred (e.g., manufacturing patient-specific orthoses), although this particular study does not focus on one specific application.


2022 ◽  
pp. 152808372110575
Author(s):  
Shohreh Mashayekhan ◽  
Hannaneh Kabir ◽  
Hadis Kamalidehghan ◽  
Roohollah Bagherzadeh ◽  
Mohammad Sajad Sorayani Bafqi

Lithium batteries have been widely used to power up implantable medical devices such as pacemakers that are often designed to treat, diagnose, and prevent different diseases. However, due to their limited capacity and lifetime, patients have to undergo a surgical procedure to replace the discharged battery. Recently, nanogenerators have been emerged and are broadly accepted since they can convert tiny biomechanical forces, such as heartbeats, into electrical energy. This study aims to manufacture a biocompatible and high-performance piezoelectric energy harvester (PEH) that is capable to be charged by the energy received from the heartbeat and store the generated voltage. In this research, a hybrid structure of poly (vinylidene fluoride) (PVDF) coupling with polyamide-11 (PA-11) was fabricated using dual electrospinning to enhance the piezoelectric properties of the intended PEH. The piezoelectric test results show an acceptable increase in nanofibers’ piezoelectric sensitivity from 62.87 mV/N to 75.75 mV/N by adding 25% (v/v) of PA-11 to PVDF, indicating the synergistic effect of PVDF and PA-11. The specimen PVDF (75% v/v)-PA-11 (25% v/v) also showed the highest mechanical strength and consequently is suggested as the optimum sample. To further enhance the efficacy and sensitivity of PEH to convert the small mechanical forces into an acceptable voltage, 15% (w/w) of barium titanate (BaTiO3) nanoparticles were added to the hybrid structure. The crystallinity and mechanical strength were noticeably increased by incorporating BaTiO3 nanoparticles into the fibrous structure, leading to a piezoelectric sensitivity of 107.52 mV/N. This result lays the groundwork for producing an effective piezoelectric patch that could be used as pacemaker batteries.


Author(s):  
Xiaodong Jin ◽  
Suping Cui ◽  
Shibing Sun ◽  
Jun Sun ◽  
Sheng Zhang ◽  
...  
Keyword(s):  

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 81
Author(s):  
Francesco Sillani ◽  
Ramis Schiegg ◽  
Manfred Schmid ◽  
Eric MacDonald ◽  
Konrad Wegener

Powder bed fusion of polymers is becoming increasingly adopted by a variety of industries to tailor the strength, weight and functionality of end-use products. To meet the high standards of the modern manufacturing industry, parts built with powder bed fusion require consistent properties and to be free of defects, which is intrinsically connected to the quality of the powder bed prior to melting. The hypothesis of this work is that the roughness of the top surface of an unmelted powder bed can serve as a proxy for the powder bed density, which is known to correlate with final part density. In this study, a laser line scan profilometer is integrated onto the recoater arm of a custom powder test bench, which is able to automatically create layers of powder. A diverse group of polymers was investigated including polyamide 12 (PA12), polyamide 11 (PA11), polypropylene (PP), and a thermoplastic elastomer (TPU) under different recoating speed in order to increase the variance of the dataset. Data analytics were employed to compare roughness to measured powder bed density and a statically significant correlation was established between them.


2021 ◽  
Vol 33 (11) ◽  
pp. 113103
Author(s):  
Zeinab Mousavi ◽  
Marie-Claude Heuzey ◽  
Musa R. Kamal ◽  
Emmanuel Flahaut ◽  
Pierre J. Carreau

2021 ◽  
pp. 102445
Author(s):  
Gabrielle R. Esposito ◽  
Theo J. Dingemans ◽  
Raymond A. Pearson

Author(s):  
Frederico G. de A. Dias ◽  
Amanda G. Veiga ◽  
Antônio Pedro A.da C.P. Gomesx ◽  
Marysilvia F. da Costa ◽  
Maria Luiza M. Rocco
Keyword(s):  

2021 ◽  
pp. 51795
Author(s):  
Do Van Cong ◽  
Nguyen Vu Giang ◽  
Tran Huu Trung ◽  
Thai Hoang ◽  
Tran Dai Lam ◽  
...  

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