Modulation of the PLLA Morphology through Racemic Nucleation to Reach Functional Properties Required by 3D Printed Durable Applications

This paper presents an alternative means for enhancing the durability of poly (L-lactide) (PLLA) by racemic nucleation following stereo-complexation with a selected poly (D-lactide) (PLDA). The compounds are obtained by melt blending of a PLLA grade, previously designed for 3D printing but with a low heat deflection temperature and impact resistance, with grades of PLDA differing in their molecular weight (Mw), D-lactide content (DS) and concentration. Our method considered how to reveal the racemic nucleation caused by stereo-complexation and its influence on functional properties. The FTIR study we performed showed that, depending on Mw, DS and concentration of the stereo-complexer (PDLA) used, bigger or smaller spectral changes can occur. The stereo-complexation was confirmed by the DSC analysis and, for the selected compound, by the POM, SEM, AFM microscopies, functional property and shapeability as 3D printing filaments. All the obtained results sustain the idea that, if a PLLA with Mw of 4.5 × 104 g·mol−1 is modified with PDLA with a medium Mw of 11.6 × 104 g·mol−1, medium DS of 4% and 1% concentration, a racemic nucleation is possible. It produces a racemic polylactic acid (PDLLA) with improved durability and good shapeability as 3D printing filaments. These results are explicable if the dependence of the intermolecular interactions appears between the PLLA and stereo-complexer PDLA. To enlarge the durable applicability of racemic polylactic acid (PDLLA), future research should identify other parameters controling the PLA stereo-complexing as the intensifying the mobility of the macromolecules, the finding of the optimal recemic cristalization window.

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Fused Filament Fabrication 3D Printed Polylactic Acid Electroosmotic Pumps

Lab on a Chip ◽

10.1039/d1lc00452b ◽

2021 ◽

Author(s):

Liang Wu ◽

Stephen Beirne ◽

Joan-Marc Cabot Canyelles ◽

Brett Paull ◽

Gordon G. Wallace ◽

...

Keyword(s):

Additive Manufacturing ◽

3D Printing ◽

Polylactic Acid ◽

Fused Filament Fabrication ◽

Flexible Approach ◽

Electroosmotic Pump ◽

3D Printed ◽

Electroosmotic Pumps

Additive manufacturing (3D printing) offers a flexible approach for the production of bespoke microfluidic structures such as the electroosmotic pump. Here a readily accessible fused filament fabrication (FFF) 3D printing...

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Application of Pickering emulsion and 3D printing for personalized nutrition. Part II: Functional properties of reduced-fat 3D printed cheese analogues

Colloids and Surfaces A Physicochemical and Engineering Aspects ◽

10.1016/j.colsurfa.2021.126760 ◽

2021 ◽

pp. 126760

Author(s):

Mahdiyar Shahbazi ◽

Henry Jäger ◽

Rammile Ettelaie

Keyword(s):

3D Printing ◽

Functional Properties ◽

Pickering Emulsion ◽

Personalized Nutrition ◽

Reduced Fat ◽

3D Printed ◽

Cheese Analogues

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Mechanical Properties of 3D-Printed Wood-Plastic Composites

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.777.499 ◽

2018 ◽

Vol 777 ◽

pp. 499-507 ◽

Cited By ~ 4

Author(s):

Ossi Martikka ◽

Timo Kärki ◽

Qing Ling Wu

Keyword(s):

Mechanical Properties ◽

Composite Materials ◽

3D Printing ◽

Impact Strength ◽

Polylactic Acid ◽

Wood Plastic Composite ◽

Wood Plastic Composites ◽

Plastic Composite ◽

Plastic Composites ◽

3D Printed

3D printing has rapidly become popular in both industry and private use. Especially fused deposition modeling has increased its popularity due to its relatively low cost. The purpose of this study is to increase knowledge in the mechanical properties of parts made of wood-plastic composite materials by using 3D printing. The tensile properties and impact strength of two 3D-printed commercial wood-plastic composite materials are studied and compared to those made of pure polylactic acid. Relative to weight –mechanical properties and the effect of the amount of fill on the properties are also determined. The results indicate that parts made of wood-plastic composites have notably lower tensile strength and impact strength that those made of pure polylactic acid. The mechanical properties can be considered sufficient for low-stress applications, such as visualization of prototypes and models or decorative items.

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DESIGN OF A 3D-PRINTED THREE-CLAW ROBOTIC GRIPPER END-EFFECTOR

ASEAN Engineering Journal ◽

10.11113/aej.v11.17865 ◽

2021 ◽

Vol 11 (4) ◽

pp. 70-79

Author(s):

Dino Dominic Forte Ligutan ◽

Argel Alejandro Bandala ◽

Jason Limon Española ◽

Richard Josiah Calayag Tan Ai ◽

Ryan Rhay Ponce Vicerra ◽

...

Keyword(s):

3D Printing ◽

Polylactic Acid ◽

Grip Force ◽

Thermoplastic Polyurethane ◽

Robotic Arm ◽

End Effector ◽

Design Considerations ◽

3D Printed ◽

Materials Used ◽

Metal Work

The development of a novel 3D-printed three-claw robotic gripper shall be described in this paper with the goal of incorporating various design considerations. Such considerations include the grip reliability and stability, grip force maximization, wide object grasping capability. Modularization of its components is another consideration that allows its parts to be easily machined and reusable. The design was realized by 3D printing using a combination of tough polylactic acid (PLA) material and thermoplastic polyurethane (TPU) material. In practice, additional tolerances were also considered for 3D printing of materials to compensate for possible expansion or shrinkage of the materials used to achieve the required functionality. The aim of the study is to explore the design and eventually deploy the three-claw robotic gripper to an actual robotic arm once its metal work fabrication is finished.

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Enhancement of the Compressive Strength of 3D-Printed Polylactic Acid(PLA) by Controlling Internal Pattern

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1023.75 ◽

2021 ◽

Vol 1023 ◽

pp. 75-81

Author(s):

Aappo Mustakangas ◽

Atef Hamada ◽

Antti Järvenpää

Keyword(s):

Compressive Strength ◽

3D Printing ◽

Polylactic Acid ◽

Optical Microscope ◽

Fused Filament Fabrication ◽

Loading Direction ◽

Compressive Flow ◽

3D Printed ◽

Cost Efficient ◽

Loading Axis

Cost-efficient 3D-printing can create a lot of new opportunities in engineering as it enables rapid prototyping of models and functional parts. In the present study, Polylactic acid (PLA) cubic specimens with different types of infill patterns (IPs), rectilinear, grid and cuboid, were additively manufactured by Fused Filament Fabrication 3D-printing. The PLA cubes are fabricated with one perimeter and different IPs density (10, 20, and 30%). Subsequently, the compressive strengths of the PLA materials were measured in two loading directions, i.e., the layers building direction is parallel (PD) to the loading axis and perpendicular (ND) to the loading direction. An optical microscope was used to examine the deformed IPs in both loading directions. The compressive flow stress curves of the PLA cubes infilled with rectilinear and grid patterns exhibited strong fluctuations with lower compressive strengths in the loading direction along ND. The PLA with 30% grid IP revealed a superior strength of ~12 kN in the loading direction along PD. On the contrary, the same material exhibited a worst compressive strength 3 kN along ND.

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Clinical Applications of Patient-Specific 3D Printed Models in Cardiovascular Disease: Current Status and Future Directions

Biomolecules ◽

10.3390/biom10111577 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1577

Author(s):

Zhonghua Sun

Keyword(s):

Cardiovascular Disease ◽

3D Printing ◽

Current Status ◽

Patient Specific ◽

Future Research ◽

Junior Doctors ◽

Imaging Data ◽

Training Tool ◽

Complex Anatomy ◽

3D Printed

Three-dimensional (3D) printing has been increasingly used in medicine with applications in many different fields ranging from orthopaedics and tumours to cardiovascular disease. Realistic 3D models can be printed with different materials to replicate anatomical structures and pathologies with high accuracy. 3D printed models generated from medical imaging data acquired with computed tomography, magnetic resonance imaging or ultrasound augment the understanding of complex anatomy and pathology, assist preoperative planning and simulate surgical or interventional procedures to achieve precision medicine for improvement of treatment outcomes, train young or junior doctors to gain their confidence in patient management and provide medical education to medical students or healthcare professionals as an effective training tool. This article provides an overview of patient-specific 3D printed models with a focus on the applications in cardiovascular disease including: 3D printed models in congenital heart disease, coronary artery disease, pulmonary embolism, aortic aneurysm and aortic dissection, and aortic valvular disease. Clinical value of the patient-specific 3D printed models in these areas is presented based on the current literature, while limitations and future research in 3D printing including bioprinting of cardiovascular disease are highlighted.

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COVID-19 and a novel initiative to improve safety by 3D printing personal protective equipment parts from computed tomography

10.21203/rs.3.rs-31671/v1 ◽

2020 ◽

Cited By ~ 1

Author(s):

John Cote ◽

John Haggstrom ◽

Ranuga Vivkanandan ◽

Kristin Ann Coté ◽

Daniel Real ◽

...

Keyword(s):

Computed Tomography ◽

3D Printing ◽

Fused Deposition Modeling ◽

Future Research ◽

Short Supply ◽

Fused Deposition ◽

Electronic Caliper ◽

3D Printed ◽

Original Part ◽

Improved Accuracy

Abstract Background Powered air-purifying respirators are in short supply and can break down with extended use. Replacement parts can become hard to acquire. The aim of this study was to create an innovative quality improvement proof of concept using rapid prototyping. Methods Here we report three cases of 3D printed powered air-purifying respirator parts. 3D printing was performed on all parts using fused deposition modeling with standard polylactic acid, in the same way that presurgical models would be created. Measurements using an electronic caliper as well as CT scans were used to compare an original part to its corresponding 3D printed parts for accuracy. Results Electronic caliper and computed tomography measurements both showed accuracy consistant with current published norms. Conclusions Ultimately, there will be questions surrounding intellectual property, effectiveness and potential long-term safety for these types of 3D printed parts. Future research should look into the addition of specific nanoparticles from the position of cost, efficacy, safety and improved accuracy.

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Effect of Porosity and Crystallinity on 3D Printed PLA Properties

Polymers ◽

10.3390/polym11091487 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1487 ◽

Cited By ~ 19

Author(s):

Yuhan Liao ◽

Chang Liu ◽

Bartolomeo Coppola ◽

Giuseppina Barra ◽

Luciano Di Maio ◽

...

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Additive Manufacturing ◽

3D Printing ◽

Polylactic Acid ◽

Complex Geometry ◽

Fused Filament Fabrication ◽

3D Printed ◽

Physical Changes ◽

Crystalline Forms

Additive manufacturing (AM) is a promising technology for the rapid tooling and fabrication of complex geometry components. Among all AM techniques, fused filament fabrication (FFF) is the most widely used technique for polymers. However, the consistency and properties control of the FFF product remains a challenging issue. This study aims to investigate physical changes during the 3D printing of polylactic acid (PLA). The correlations between the porosity, crystallinity and mechanical properties of the printed parts were studied. Moreover, the effects of the build-platform temperature were investigated. The experimental results confirmed the anisotropy of printed objects due to the occurrence of orientation phenomena during the filament deposition and the formation both of ordered and disordered crystalline forms (α and δ, respectively). A heat treatment post-3D printing was proposed as an effective method to improve mechanical properties by optimizing the crystallinity (transforming the δ form into the α one) and overcoming the anisotropy of the 3D printed object.

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An overview on joining/welding as post-processing technique to circumvent the build volume limitation of an FDM-3D printer

Rapid Prototyping Journal ◽

10.1108/rpj-10-2020-0265 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Vivek Kumar Tiwary ◽

Arunkumar P. ◽

Vinayak R. Malik

Keyword(s):

3D Printing ◽

Literature Review ◽

Adhesive Bonding ◽

Business Leaders ◽

Future Research ◽

3D Printer ◽

Content Type ◽

Friction Stir ◽

Fused Deposition ◽

3D Printed

Purpose Three-dimensional (3D) printing, one of the important technological pillars of Industry 4.0, is changing the landscape of future manufacturing. However, the limited build volume of a commercially available 3D printer is one inherent constraint, which holds its acceptability by the manufacturing business leaders. This paper aims to address the issue by presenting a novel classification of the possible ways by which 3D-printed parts can be joined or welded to achieve a bigger-sized component. Design/methodology/approach A two-step literature review is performed. The first section deals with the past and present research studies related to adhesive bonding, mechanical interlocking, fastening and big area additive manufacturing of 3D printed thermoplastics. In the second section, the literature searches were focused on retrieving details related to the welding of 3D printed parts, specifically related to friction stir welding, friction (spin) welding, microwave and ultrasonic welding. Findings The key findings of this review study comprise the present up-to-date research developments, pros, cons, critical challenges and the future research directions related to each of the joining/welding techniques. After reading this study, a better understanding of how and which joining/welding technique to be applied to obtain a bigger volume 3D printed component will be acquired. Practical implications The study provides a realistic approach for the joining of 3D printed parts made by the fused deposition modeling (FDM) technique. Originality/value This is the first literature review related to joining or welding of FDM-3D printed parts helping the 3D printing fraternity and researchers, thus increasing the acceptability of low-cost FDM printers by the manufacturing business leaders.

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