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.

Available Mechanical and Chemical Properties of Natural Fibers

2018 ◽  
pp. 110-136
Keyword(s):  
Mechanical Properties ◽  
Moisture Absorption ◽  
Natural Fiber ◽  
Low Cost ◽  
Natural Fibers ◽  
Chemical Properties ◽  
Low Energy ◽  
Synthetic Fibers ◽  
The Right ◽  
And Chemical Properties

Natural fibers are so attracting in comparison to synthetic fibers since they exhibit good properties like the low cost, good specific mechanical properties and their requirements of low energy during production. However, natural fibers hold some drawbacks which must be consider in comparison to the synthetic fibers like their high moisture absorption, low mechanical properties, heat resistance and durability and the variation in their prices and quality. In order to choose the suitable natural fiber for the selected application, their mechanical and chemical properties can be helpful for taking the right decision. In this chapter, a wide research is done in order to provide as much as possible the available mechanical and chemical properties of natural fibers of bast, leaf, seed, stalk, and wood categories from the most trusted publications. The specific mechanical properties of natural fibers are then calculated for a better comparison at the level of composites.

scholarly journals Comparative Microstructural Study on Mechanical Properties of Concrete Enhanced with Graphite and Graphene Compound

2018 ◽  
Vol 7 (4.5) ◽  
pp. 91
Author(s):  
P. Sudheer ◽  
Dr S. Chandramouli
Keyword(s):  
Mechanical Properties ◽  
Raw Materials ◽  
Chemical Properties ◽  
Nano Materials ◽  
Nano Technology ◽  
Microstructural Investigation ◽  
Before And After ◽  
Materials Used ◽  
Physical And Chemical ◽  
And Chemical Properties

The present study is based on nano technology and came up with the idea of introducing nanoparticles in the raw materials used for construction. Nano materials are available in three principal shapes 0, 1 and 2 Dimensional nanoparticles. 0D and 1D nanofibers are such as carbon nanotubes and nanosilica compounds. This study has investigated the physical and chemical properties of graphite and graphene compound and its applicability in construction industry.  Graphene has created interest as it is believed to improve the strength of concrete allowing the possibility of controlling properties of concrete. In this work graphene is used as a reinforcing additive in cement-based mortar and concrete. Own Graphene compound is prepared using conventional graphite and concentrated hydrogen peroxide in the laboratory due to the unavailability of graphene. As a part of microstructural investigation, SEM and EDS analysis on graphite and graphene compounds before and after implementation are carried out in the laboratory. Then the two compounds are replaced as a part of small percentage in cement mortar cubes casted for various proportions. The mechanical properties of cement-based composites are studied after incorporating of graphite and graphene compounds at low dosages in concrete and then the results are compared. 

INFLUENCE OF THE AGE OF EPOXY DISPERSION ON THE EFFECTIVENESS OF PROTECTION OF CONCRETE SURFACES

2012 ◽  
Vol 4 (2) ◽  
pp. 37-44
Author(s):  
Michal Stehlík
Keyword(s):  
Mechanical Properties ◽  
Considerable Increase ◽  
Chemical Resistance ◽  
Chemical Properties ◽  
Mechanical Tests ◽  
Laser Diffraction ◽  
The Other ◽  
Subsequent Effect ◽  
Adhesive Capacity ◽  
And Chemical Properties

The scope of this paper is to test stability and mechanical and chemical properties of a modern freshly mixed epoxy dispersion, and as a variant, of a dispersion which is two years old. During ageing, the dispersion particles probably agglomerate, which is tested by laser diffraction and by sedimentation in a cylinder. Physical-mechanical tests assess the appearance, drying speed and mechanical properties of the film. Chemical tests focus on assessing the resistance of films of dispersions of different ages to common chemicals and to chemical defrosting agents. It is possible to say that two years of dispersion storage lead to a considerable increase in the diameter of a certain number of dispersion particles with the subsequent effect of increasing the sedimentation speed. The hardened film of a two-year old dispersion dries faster, has a rougher surface, is softer, but on the other hand, is less elastic and its adhesive capacity to the substrate is worse. Its chemical resistance is decreased but its defrosting agent resistance remains good. Due to the two-year storage of the epoxy dispersion, most of the monitored parameters decrease, nevertheless, certain protection of concrete structures by a hardened film of such epoxy dispersions is possible.

scholarly journals Properties of Agave angustifolia Haw. bagasse before and after its composting.

2015 ◽  
Vol 6 (4) ◽  
pp. 418 ◽  
Author(s):  
Gabino A. Martínez-Gutiérrez ◽  
Yolanda D. Ortiz-Hernández ◽  
Teodulfo Aquino-Bolaños ◽  
Angélica Bautista-Cruz ◽  
Juana Y. López-Cruz
Keyword(s):  
Physicochemical Properties ◽  
Physical Properties ◽  
Dry Matter ◽  
Chemical Properties ◽  
Reference Intervals ◽  
The Other ◽  
Agave Angustifolia ◽  
Before And After ◽  
Mature Compost ◽  
And Chemical Properties

The industry of mezcal (Agave spp.) in Oaxaca, Mexico annually generates more than one hundred thousand tons of bagasse. With the aim of using this by-product as an alternative organic substratum, there were analyzed the physical, physicochemical and chemical properties before and after the composting of the bagasse of the A. angustifolia Haw with 0, 90 and 180 days of aging. Before the composting, all the physicochemical properties were different for the aging periods except for humidity and dry matter. During the composting process the temperature of the three materials was superior to 58oC, and after 105 days it was obtained mature compost, free of feces. The physicochemical and chemical properties of the three composts were different for the aging periods and most of them were not placed between the reference intervals, except in the C/N relation, contrary to most of the other physical properties.

Identification of Amber and the Copal under Heat Pressurized Process

2012 ◽  
Vol 554-556 ◽  
pp. 2112-2115
Author(s):  
Hui Li ◽  
Xuan Wang ◽  
Yong Zhu ◽  
Qin Ren
Keyword(s):  
Chemical Properties ◽  
Peak Position ◽  
Exothermic Peak ◽  
Endothermic Peak ◽  
Scanning Calorimetry ◽  
Natural Resin ◽  
Before And After ◽  
Artificial Heat ◽  
Physical And Chemical ◽  
And Chemical Properties

Amber and copal belong to the natural resin, which are similar and transitional in the physical and chemical properties. The artificial heat-pressurized treatment is contributed to the polymerization of the natural copal, and turns into green, yellow-green and deep orange-yellow copal. It is very difficult to identify amber from the heat- pressurized treatment copal only based on the gemological parameters.The thermal behavior of amber and the copal before and after heat-pressurized treatment were analyzed by means of differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy(FTIR) and nuclear magnetic resonance(NMR). The results show that amber exists an evident endothermic peak around 123~132°C, and copal reveals an obvious endothermic peak at about 174~178°C, and the heat pressurized treatment copal occurs a clear exothermic peak around 150~152°C. The differences between endothermic or exothermic transition and peak position reveal occurring thermal oxidation or the bond breaking or the melting, which are of great significance in the identification.

Study of Whiskers to be Used in Composite Materials

2021 ◽  
Vol 316 ◽  
pp. 51-55
Author(s):  
Tamara I. Shishelova ◽  
Vadim V. Fedchishin ◽  
Mikhail A. Khramovskih
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Chemical Properties ◽  
High Strength ◽  
Rapid Expansion ◽  
Physical And Chemical Properties ◽  
Reinforcement Fiber ◽  
Object Of Study ◽  
Physical And Chemical ◽  
And Chemical Properties

Rapid expansion of technologies poses higher requirements to structural materials and items made of them. Conventional materials are being replaced by composite materials (composites). Different additives enhancing the properties of initial materials are used as reinforcement fibers of composites. Utilization of micro-and nanosize particles for production of present-day materials is paid much attention to. Whiskers are among such materials. These crystals have high strength, high chemical and temperature resistance. But for rational utilization of whickers of different chemical composition in composite materials one should know their physical and chemical properties. Objectives of the paper: to study physical and chemical properties of whiskers in different compounds, their composition and structure; to prove experimentally the feasibility of utilizing whiskers as a reinforcement fiber of composite materials. Object of study: specimens of whiskers of silicon nitride (Si3N4), aluminum oxide (Al2O3), aluminum nitride (AlN), and mullite (Al6Si2O13). Methods of investigation: thermal study of specimens, study of mechanical properties and chemical strength, and IR-spectroscopy. Results of study: specimens of whiskers have been studied and their mechanical properties have been tabulated for comparison. Extensive thermal investigation was followed by deduction of regularities and identification of chemical properties of whiskers. IR-spectra of whiskers have been studied and conclusions on molecular composition and on presence of impurities in some whiskers have been made.

scholarly journals Biocompatible Material from Indonesian Natural Resource of Wild Silkmoth Cocoon

2018 ◽  
Vol 1 (2) ◽  
pp. 47
Author(s):  
Tjokorda Gde Tirta Nindhia ◽  
Zdenek Knejzlík ◽  
Tomáš Ruml ◽  
I Wayan Surata ◽  
Tjokorda Sari Nindhia
Keyword(s):  
Mechanical Properties ◽  
Natural Resource ◽  
Chemical Properties ◽  
Hot Water ◽  
Physical And Chemical Properties ◽  
Living Things ◽  
Biocompatibility Testing ◽  
Good Biocompatibility ◽  
Physical And Chemical ◽  
And Chemical Properties

Silk can be produced by spider or insect and have prospect as biomaterial for regenerative healing in medical treatment. Silk having physical and chemical properties that support biocompatibility in the living things..In this research, silk that was obtained from Indonesia natural resource of Attacus atlas silkmoth was explored and then will be  developed for biocompatible biomaterial. The treatment with NaOH was developed to separate the fiber from the cocoon. The obtained fiber is investigated its mechanical property by performing tensile test for single fiber. The biocompatibility testing was conducted with human cell (osteosarccoma) cultivation. The result identify that separation by using NaOH yield better better mechanical properties comparing konvenstional method with boiling in hot water. Biocompatibility testing indicate that the the fiber having good biocompatibility.

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 Some physical and chemical properties of substrates designed for container production of spruce (Picea abies (L) Karst)

2004 ◽  
pp. 79-90
Author(s):  
Vesna Vratusa
Keyword(s):  
Woody Plants ◽  
Low Cost ◽  
Chemical Properties ◽  
Foreign Markets ◽  
Urban Green Spaces ◽  
Nursery Production ◽  
Countries In Transition ◽  
Physical And Chemical ◽  
And Chemical Properties

Efficient nursery production of woody plants, as well as the level of their successful application in urban green spaces, greatly depends upon properties of substrates in which these individuals grow, develop and endure. Furthermore, quality of substrate does not only affect the quality of future product (plant individual or green space), but distinctly determines its price. This element, extremely significant for all countries in transition, thus Serbia as well, commands finding ways of making qualitative, but least expensive substrate. The most logical solution is to use mixtures/substrates of precisely defined properties, composed of domestic components. Results presented in this paper imply that it is possible to create precisely such standard mixtures from domestic resources at relatively low cost, adjusted to needs of particular species, which would ultimately lead to successful, non-expensive nursery production and application of produced stock, both on domestic and foreign markets.

scholarly journals Produksi Biofuel Dari Limbah Cpo Dengan Katalis Berbasis Titanium Oksida Dan Implementasinya Pada Pembelajaran Kimia

2017 ◽  
Vol 1 (1) ◽  
pp. 19-24
Author(s):  
Nurlia Latifah ◽  
Agus Sundaryono ◽  
Rina Elvia
Keyword(s):  
Methyl Ester ◽  
Learning Outcomes ◽  
Alternative Energy ◽  
Chemical Properties ◽  
Student Learning Outcomes ◽  
Tio2 Catalyst ◽  
Before And After ◽  
Cracking Process ◽  
Physical And Chemical ◽  
And Chemical Properties

Conversion of CPO waste into biofuel is one of the efforts to find alternative energy to overcome Indonesia's energy crisis. The resulting methyl ester was further processed into biofuel by cracking process with Ni/TiO2 and Co/TiO2 catalysts at temperature > 350oC for 2.5 hours followed by distillation. Educational research was done by doing the learning process by using biofuel module. The optimum biofuel yield was obtained from cracking methyl ester with 5% Ni/TiO2 catalyst and 3% Co/TiO2 catalyst respectively of 66,67 and 61,90%. The physical and chemical properties of cracked biofuels with Ni/TiO2 and Co/ TiO2 catalysts have complied with ASTM standards for biofuel except acid numbers. There is an increase in student learning outcomes before and after using the module. 

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