Fabrication of polylactic acid/halloysite nanotube scaffolds by foam injection molding for tissue engineering

2019 ◽  
Vol 41 (2) ◽  
pp. 757-767
Author(s):  
Meltem Eryildiz ◽  
Mirigul Altan
Keyword(s):  
Tissue Engineering ◽  
Injection Molding ◽  
Polylactic Acid ◽  
Halloysite Nanotube ◽  
Foam Injection Molding

Preparation of open microcellular polylactic acid foams with a microfibrillar additive using coreback foam injection molding processes

2018 ◽  
Vol 54 (4) ◽  
pp. 765-784 ◽  
Author(s):  
Shota Ishihara ◽  
Yuta Hikima ◽  
Masahiro Ohshima
Keyword(s):  
Injection Molding ◽  
Polylactic Acid ◽  
Bubble Nucleation ◽  
Number Density ◽  
Cell Content ◽  
Open Cell ◽  
Cooling Conditions ◽  
Nucleation Sites ◽  
Fast Cooling ◽  
Foam Injection Molding

Open microcellular polylactic acid foams with a fibrous polytetrafluoroethylene additive were prepared by a coreback foam injection molding technique. The effects of this fibrous additive on the foam cell structure were investigated. Fibrous polytetrafluoroethylene forms a network structure in polylactic acid in metering and mixing processes. The fibrous polytetrafluoroethylene network increased the viscoelasticity of polylactic acid and provided polylactic acid with a strain-hardening property. The network also provided heterogeneous bubble nucleation sites for physical foaming. However, because of the slow crystallization rate of polylactic acid, the fibrous polytetrafluoroethylene additive did not promote the nucleation of polylactic acid crystals under fast cooling conditions. During fast cooling, such as injection molding cooling conditions, the crystals induced by the fibrous polytetrafluoroethylene network could not behave as bubble nucleation sites. Thus, changes in rheological properties and the increased number of heterogeneous sites contributed to the decrease in cell size, the increase in the number density of cells and the increase in the open cell content. As the number density of cells increased, the cell walls with the fibrous polytetrafluoroethylene fibrous additive became so thin that they could be easily fibrillated by a stretching operation during the coreback operation, while their strain-hardening property prevented the walls from complete breakage. Synergistically conducting cell reduction and stretching (coreback) operations, high expansion ratio foams with high open cell content were prepared. When we adjusted the foaming temperature and holding time, five-fold expansion (i.e. 80% void ratio) foams with cell diameters less than 25 µm and open cell contents (OCC) higher than 80% were produced.

Effect of processing condition on properties of polylactic acid parts obtained by foam injection molding

2016 ◽  
Vol 53 (5) ◽  
pp. 491-502 ◽  
Author(s):  
Valentina Volpe ◽  
Roberto Pantani
Keyword(s):  
Mechanical Properties ◽  
Injection Molding ◽  
Polylactic Acid ◽  
Flow Rate ◽  
Flexural Modulus ◽  
Processing Condition ◽  
Blowing Agent ◽  
Injection Flow Rate ◽  
Injection Flow ◽  
Foam Injection Molding

Foam injection molding is a processing technology particularly interesting for biodegradable polymers, which present a very narrow processing window, with the suitable processing temperatures close to the degradation conditions. The addition of a physical blowing agent, besides decreasing the final part weight, reduces both the viscosity and the glass transition temperature of the polymer melt, allowing the processability of these materials at lower temperatures. In this work, structural foams of polylactic acid with nitrogen as physical blowing agent were obtained by foam injection molding. In particular, the effects of back pressure, namely the pressure imposed inside of the cylinder when the screw is returning back to prepare a new amount of material to be injected, and of the injection flow rate on foaming and mechanical properties of the molded parts was assessed. It was found that the samples molded adopting a higher injection flow rate are shorter than those injected at lower flow rate, and this result was ascribed to the large compressibility of the injected shot. As far as the mechanical properties of the foamed parts, it was found that the modulus decreases with decreasing density. However, the density reduction is not the only significant parameter, but also the morphology of the foams should be taken into account in order to justify the differences between tensile and flexural modulus.

scholarly journals Characterization of thermoplastic polyurethane/polylactic acid (TPU/PLA) tissue engineering scaffolds fabricated by microcellular injection molding

2013 ◽  
Vol 33 (8) ◽  
pp. 4767-4776 ◽  
Author(s):  
Hao-Yang Mi ◽  
Max R. Salick ◽  
Xin Jing ◽  
Brianna R. Jacques ◽  
Wendy C. Crone ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Injection Molding ◽  
Polylactic Acid ◽  
Thermoplastic Polyurethane ◽  
Tissue Engineering Scaffolds ◽  
Microcellular Injection Molding

Piezoelectric Performance of Microcellular Polypropylene Foams Fabricated Using Foam Injection Molding as a Potential Scaffold for Bone Tissue Engineering

2020 ◽  
Vol 59 (6) ◽  
pp. 376-389 ◽  
Author(s):  
Ali Samadi ◽  
Rezgar Hasanzadeh ◽  
Taher Azdast ◽  
Hossein Abdollahi ◽  
Payam Zarrintaj ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Injection Molding ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Foam Injection Molding ◽  
Piezoelectric Performance

scholarly journals Preparation of Open Cellular Polylactic Acid Foam by Coreback Foam Injection Molding

Seikei-Kakou ◽  
2018 ◽  
Vol 30 (9) ◽  
pp. 492-498
Author(s):  
Shota Ishihara ◽  
Masahiro Ohshima
Keyword(s):  
Injection Molding ◽  
Polylactic Acid ◽  
Foam Injection Molding

Clindamycin-loaded nanofibers of polylactic acid, elastin and gelatin for use in tissue engineering

2021 ◽  
Author(s):  
M. M. Castillo-Ortega ◽  
I. Y. López-Peña ◽  
D. E. Rodríguez-Félix ◽  
T. Del Castillo-Castro ◽  
J. C. Encinas-Encinas ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Polylactic Acid

Tissue engineering needs new biomaterials: Poly(xylitol-dodecanedioic acid)–co-polylactic acid (PXDDA-co-PLA) and its nanocomposites

2021 ◽  
Vol 152 ◽  
pp. 110469
Author(s):  
Amir Sotoudeh ◽  
Goldis Darbemamieh ◽  
Vahabodin Goodarzi ◽  
Shahrokh Shojaei ◽  
Azadeh Asefnejad
Keyword(s):  
Tissue Engineering ◽  
Polylactic Acid ◽  
Dodecanedioic Acid

scholarly journals Energy and Eco-Impact Evaluation of Fused Deposition Modeling and Injection Molding of Polylactic Acid

2021 ◽  
Vol 13 (4) ◽  
pp. 1875
Author(s):  
Emmanuel Ugo Enemuoh ◽  
Venkata Gireesh Menta ◽  
Abdulaziz Abutunis ◽  
Sean O’Brien ◽  
Labiba Imtiaz Kaya ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Injection Molding ◽  
Polylactic Acid ◽  
Fused Deposition Modeling ◽  
Plastic Injection Molding ◽  
Measurement Models ◽  
Fused Deposition ◽  
Dog Bone ◽  
Deposition Modeling ◽  
Plastic Injection

There is limited knowledge about energy and carbon emission performance comparison between additive fused deposition modeling (FDM) and consolidation plastic injection molding (PIM) forming techniques, despite their recent high industrial applications such as tools and fixtures. In this study, developed empirical models focus on the production phase of the polylactic acid (PLA) thermoplastic polyester life cycle while using FDM and PIM processes to produce American Society for Testing and Materials (ASTM) D638 Type IV dog bone samples to compare their energy consumption and eco-impact. It was established that energy consumption by the FDM layer creation phase dominated the filament extrusion and PLA pellet production phases, with, overwhelmingly, 99% of the total energy consumption in the three production phases combined. During FDM PLA production, about 95.5% of energy consumption was seen during actual FDM part building. This means that the FDM process parameters such as infill percentage, layer thickness, and printing speed can be optimized to significantly improve the energy consumption of the FDM process. Furthermore, plastic injection molding consumed about 38.2% less energy and produced less carbon emissions per one kilogram of PLA formed parts compared to the FDM process. The developed functional unit measurement models can be employed in setting sustainable manufacturing goals for PLA production.

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