Effects of Gamma Irradiation Upon the Mechanical and Chemical Properties of 3D-Printed Samples of Polylactic Acid

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Conrad West ◽  
Robert McTaggart ◽  
Todd Letcher ◽  
Douglas Raynie ◽  
Ranen Roy
Keyword(s):  
Polylactic Acid ◽  
Chemical Properties ◽  
Waste Streams ◽  
Exponential Functions ◽  
Destructive Testing ◽  
Space Applications ◽  
Mechanical Responses ◽  
Decomposition Processes ◽  
3D Printed ◽  
And Chemical Properties

3D printing offers the opportunity to design and make replacement parts to exacting specifications when needed. This is particularly helpful for space applications where stand-alone replacement mechanisms are required. Samples of 3D-printed polylactic acid (PLA) were subjected with up to 200 kGy of gamma radiation from a Cobalt-60 irradiator. The mechanical responses to destructive testing were successfully modeled with a combination of linear and exponential functions and may be understood given the underlying chemical changes due to said radiation exposures. We find that for doses up to 50 kGy, the performance of 3D-printed PLA is largely unaffected, which is beneficial for applications in space and in medicine. At larger doses, it appears that decomposition processes win out over cross-linking, which may aid in the degradation of PLA in waste streams.

scholarly journals 3D Printed Laminated CaCO3-Nanocellulose Films as Controlled-Release 5-Fluorouracil

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 986 ◽  
Author(s):  
Denesh Mohan ◽  
Nur Fatin Khairullah ◽  
Yan Ping How ◽  
Mohd Shaiful Sajab ◽  
Hatika Kaco
Keyword(s):  
Drug Delivery ◽  
Chemical Properties ◽  
Pharmaceutical Compounds ◽  
The Body ◽  
Therapeutic Effects ◽  
Layer By Layer ◽  
3D Printed ◽  
Time Required ◽  
Uptake And Release ◽  
And Chemical Properties

Drug delivery constitutes the formulations, technologies, and systems for the transport of pharmaceutical compounds to specific areas in the body to exert safe therapeutic effects. The main criteria for selecting the correct medium for drug delivery are the quantity of the drug being carried and the amount of time required to release the drug. Hence, this research aimed to improve the aforementioned criteria by synthesizing a medium based on calcium carbonate-nanocellulose composite and evaluating its efficiency as a medium for drug delivery. Specifically, the efficiency was assessed in terms of the rates of uptake and release of 5-fluorouracil. Through the evaluation of the morphological and chemical properties of the synthesized composite, the established 3D printing profiles of nanocellulose and CaCO3 took place following the layer-by-layer films. The 3D printed double laminated CaCO3-nanocellulose managed to release the 5-fluorouracil as an effective single composition and in a time-controlled manner.

scholarly journals Graphite Modified Polylactide (PLA) for 3D Printed (FDM/FFF) Sliding Elements

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1250 ◽  
Author(s):  
Robert E. Przekop ◽  
Maciej Kujawa ◽  
Wojciech Pawlak ◽  
Marta Dobrosielska ◽  
Bogna Sztorch ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Stress ◽  
Low Cost ◽  
Chemical Properties ◽  
Spare Parts ◽  
The Other ◽  
Graphite Content ◽  
Before And After ◽  
3D Printed ◽  
And Chemical Properties

With the development of 3D printing technology, there is a need to produce printable materials with improved properties, e.g., sliding properties. In this paper, the authors present the possibilities of producing composites based on biodegradable PLA with the addition of graphite. The team created composites with the following graphite weight contents: 1%, 2.5%, 5%, 7.5%, and 10%. Neat material was also subjected to testing. Tribological, mechanical, and chemical properties of the mentioned materials were examined. Measurements were also made after keeping the samples in ageing and climatic ovens. Furthermore, SEM observations of samples before and after friction tests were carried out. It was demonstrated that increasing graphite content caused a significant decrease in wear (PLA + 10% graphite had a wear rate three times lower than for a neat material). The addition of graphite did not adversely affect most of the other properties, but it ought to be noted that mechanical properties changed significantly. After conditioning in a climatic oven PLA + 10% graphite has (in comparison with neat material) 11% lower fracture stress, 47% lower impact strength, and 21% higher Young’s modulus. It can be certainly stated that the addition of graphite to PLA is a step towards obtaining a material that is low-cost and suitable for printing sliding spare parts.

Study of the Chemical and Physical Properties of the Fiber-Matrix Interface of Biocomposite Material Based on a Copolymer Matrix Polylactic Acid (PLA)

2019 ◽  
Vol 12 (1) ◽  
pp. 70-78
Author(s):  
Mokhtaria Ould Kada ◽  
Allel Mokaddem ◽  
Bendouma Doumi ◽  
Mohamed Berber ◽  
Lahouari Temimi ◽  
...  
Keyword(s):  
Physical Properties ◽  
Polylactic Acid ◽  
Probabilistic Approach ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Matrix Interface ◽  
Fiber Matrix Interface ◽  
Fiber Matrix ◽  
Physical And Chemical ◽  
And Chemical Properties

Background: In this paper, we have studied the improvement of the physical and chemical properties of the fiber-matrix interface of a Biocomposite based on the copolymer polylactic acid (PLA). Methodology: We have developed an analytical model using a genetic approach to locate the interface damage under the effect of mechanical stress, temperature and humidity. Our simulation is based on Weibull's probabilistic approach and the law of water diffusion in polymer matrix, the diffusion is generated by Fick's law. Results: Our results show that the interface of Biocomposite (Starch-PLA) is the most resistant to the different constraints applied and that the physical and chemical properties of this material are much more improved compared to other materials studied by the same genetic model. Conclusion: Our calculations coincide perfectly with the conclusions of Antoine et al. who determined that natural fibers improve the physical properties of composite materials.

scholarly journals Impact of Lignin Content on the Properties of Hemicellulose Hydrogels

Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 35 ◽  
Author(s):  
Basel Al-Rudainy ◽  
Mats Galbe ◽  
Monica Arcos Hernandez ◽  
Patric Jannasch ◽  
Ola Wallberg
Keyword(s):  
Membrane Filtration ◽  
Lignin Content ◽  
Chemical Properties ◽  
Downstream Processing ◽  
Raw Material ◽  
Crosslinking Reaction ◽  
Waste Streams ◽  
Renewable Raw Material ◽  
Effect Of Impurities ◽  
And Chemical Properties

Hemicellulose is a promising renewable raw material for the production of hydrogels. This polysaccharide exists in large amounts in various waste streams, in which they are usually impure and heavily diluted. Several downstream processing methods can be combined to concentrate and purify the hemicellulose. However, such an approach can be costly; hence, the effect of impurities on the formation and properties of hydrogels must be determined. Lignin usually exists in these waste streams as a major impurity that is also difficult to separate. This compound can darken hydrogels and decrease their swellability and reactivity, as shown in many studies. Other properties and effects of lignin impurities are equally important for the end application of hydrogels and the overall process economy. In this work, we examined the feasibility of producing hydrogels from hemicelluloses that originated from sodium-based spent sulfite liquor. A combination of membrane filtration and anti-solvent precipitation was used to extract and purify various components. The influence of the purity of hemicellulose and the addition of lignosulfonates (emulated impurities in the downstream processing) to the crosslinking reaction mixture on the mechanical, thermal, and chemical properties of hydrogels was determined.

scholarly journals Surface Finishing of 3D-Printed Polymers with Selected Coatings

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2797
Author(s):  
Jure Žigon ◽  
Mirko Kariž ◽  
Matjaž Pavlič
Keyword(s):  
Lactic Acid ◽  
Substrate Surface ◽  
Chemical Properties ◽  
Acrylonitrile Butadiene Styrene ◽  
Surface Finishing ◽  
Poly Lactic Acid ◽  
Coating Film ◽  
3D Printed ◽  
And Chemical Properties ◽  
Butadiene Styrene

Surface treatment of 3D-printed objects with coatings, besides protection against environmental influences, offers the improvement of visual appearance of the printed elements. In order to design an optimum surface system, the physical and chemical properties of polymers surfaces should be well-known. In the present study, 3D-printed samples of acrylonitrile-butadiene-styrene, poly(lactic acid) and poly(lactic acid) with wood flour additive were coated with three different types of coating, namely solvent borne alkyd coating, water borne acrylic coating and coating made of acrylonitrile-butadiene-styrene diluted in acetone. The surface properties of substrates and the properties of surface systems were assessed with different methods. The results revealed the surfaces of polymers having hydrophobic character, whereas the color, gloss, surface roughness and coating film thickness of coated surfaces depend on the characteristics of particular coatings. Finally, the adhesion of coatings was shown to be appropriate, but dependent on substrate surface porosity and chemical properties of both substrate surface and coating asset.

scholarly journals Physical and Chemical Properties Characterization of 3D-Printed Substrates Loaded with Copper-Nickel Nanowires

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2680
Author(s):  
Ely Dannier V-Niño ◽  
Quentin Lonne ◽  
Andrés Díaz Lantada ◽  
Enrique Mejía-Ospino ◽  
Hugo Armando Estupiñán Durán ◽  
...  
Keyword(s):  
Glass Transition ◽  
Load Transfer ◽  
Chemical Properties ◽  
Layer By Layer ◽  
Copper Nickel ◽  
Nickel Nanowires ◽  
3D Printed ◽  
Nickel Nanowire ◽  
Laser Stereolithography ◽  
And Chemical Properties

This study deals with the laser stereolithography manufacturing feasibility of copper-nickel nanowire-loaded photosensitive resins. The addition of nanowires resulted in a novel resin suitable for additive manufacturing technologies based on layer-by-layer photopolymerization. The pure and nanowire-loaded resin samples were 3D printed in a similar way. Their morphological, mechanical, thermal, and chemical properties were characterized. X-ray computed tomography revealed that 0.06 vol % of the composite resin was filled with nanowires forming randomly distributed aggregates. The increase of 57% in the storage modulus and 50% in the hardness when loading the resin with nanowire was attributed to the load transfer. Moreover, the decrease in the glass transition temperature from 57.9 °C to 52.8 °C in the polymeric matrix with nanowires evidenced a decrease in the cross-linking density, leading to a higher mobility of the polymer chains during glass transition. Consequently, this research demonstrates the successful dispersion and use of copper-nickel nanowires as a reinforcement material in a commercial resin for laser stereolithography.

Statistical criteria of stellar population types

1966 ◽  
Vol 24 ◽  
pp. 101-110
Author(s):  
W. Iwanowska
Keyword(s):  
Stellar Population ◽  
Chemical Properties ◽  
Spectrophotometric Study ◽  
Physical And Chemical Properties ◽  
Population Type ◽  
The Galaxy ◽  
Distribution Parameters ◽  
Physical And Chemical ◽  
Statistical Criteria ◽  
And Chemical Properties

In connection with the spectrophotometric study of population-type characteristics of various kinds of stars, a statistical analysis of kinematical and distribution parameters of the same stars is performed at the Toruń Observatory. This has a twofold purpose: first, to provide a practical guide in selecting stars for observing programmes, second, to contribute to the understanding of relations existing between the physical and chemical properties of stars and their kinematics and distribution in the Galaxy.

The microstructure of a TiB2/Ti-47 Al composite material

1989 ◽  
Vol 47 ◽  
pp. 674-675
Author(s):  
O. Popoola ◽  
A.H. Heuer ◽  
P. Pirouz
Keyword(s):  
Composite Material ◽  
Ion Beam ◽  
Chemical Properties ◽  
Intermetallic Alloys ◽  
Transmission Electron ◽  
Diamond Polishing ◽  
Al Composite ◽  
The Matrix ◽  
Argon Ion ◽  
And Chemical Properties

The addition of fibres or particles (TiB2, SiC etc.) into TiAl intermetallic alloys could increase their toughness without compromising their good high temperature mechanical and chemical properties. This paper briefly discribes the microstructure developed by a TiAl/TiB2 composite material fabricated with the XD™ process and forged at 960°C.The specimens for transmission electron microscopy (TEM) were prepared in the usual way (i.e. diamond polishing and argon ion beam thinning) and examined on a JEOL 4000EX for microstucture and on a Philips 400T equipped with a SiLi detector for microanalyses.The matrix was predominantly γ (TiAl with L10 structure) and α2(TisAl with DO 19 structure) phases with various morphologies shown in figure 1.

Tailoring microstructures of materials through biomimetics

1993 ◽  
Vol 51 ◽  
pp. 500-501
Author(s):  
Mehmet Sarikaya ◽  
Ilhan A. Aksay
Keyword(s):  
Chemical Properties ◽  
Design And Synthesis ◽  
Structure Sensitive ◽  
Macro Scale ◽  
Methods Of Synthesis ◽  
Successive Level ◽  
Engineering Materials ◽  
Physical And Chemical ◽  
And Chemical Properties ◽  
Synthesis Of Materials

Biomimetics involves investigation of structure, function, and methods of synthesis of biological composite materials. The goal is to apply this information to the design and synthesis of materials for engineering applications.Properties of engineering materials are structure sensitive through the whole spectrum of dimensions from nanometer to macro scale. The goal in designing and processing of technological materials, therefore, is to control microstructural evolution at each of these dimensions so as to achieve predictable physical and chemical properties. Control at each successive level of dimension, however, is a major challenge as is the retention of integrity between successive levels. Engineering materials are rarely fabricated to achieve more than a few of the desired properties and the synthesis techniques usually involve high temperature or low pressure conditions that are energy inefficient and environmentally damaging.In contrast to human-made materials, organisms synthesize composites whose intricate structures are more controlled at each scale and hierarchical order.

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