Modification of the Mechanical Properties of Vitreous Enameled Aluminium Substrate Adding Graphene Flakes

2019 ◽  
Vol 813 ◽  
pp. 49-54 ◽  
Author(s):  
Stefano Rossi ◽  
Nicola Gasparre ◽  
Vigilio Fontanari ◽  
Attilio Compagnoni

Vitreous enamel is a very interesting materials thanks to its glassy nature, which permits to obtain high protection against corrosion and fire. In addition, the smooth surface with an elevate hardness favors good abrasion resistance. However, a negative aspect of this kind of coating is the high brittleness, which limits the application in case of impulsive or high loads. The nucleation and propagation of cracks leads to the destruction of layer integrity with loss of properties. In recent years graphene has received increasing attention as toughening addictive for organic and metal coatings as well as composite materials. This work is a first attempt to evaluate if the addition of graphene in an enamel deposit can increase its mechanical properties. The graphene was mixed with the dry frit. A milling process was then carried out before producing the torbida. In this way the formation of graphene clusters and accumulations is prevented. The addition of 1% graphene has shown to be effective in the increase of mechanical properties without negative influence on the deposit microstructure.

2017 ◽  
Vol 63 (4) ◽  
pp. 8-12
Author(s):  
Michal Návrat ◽  
Jaroslav Závada ◽  
Veronika Glogarová

Abstract The article deals with the influence of thermal pyrolytic degradation on mechanical properties of carbon fibres used in the production of composite material. The carbon fibre has been chosen as the reinforcement of composite and the resin formed a matrix (binder). During the pyrolysis process, the resin was eliminated and the carbon fibre was separated. Pyrolysis was carried out at temperatures of 450 °C, 550 °C and 650 °C. Subsequently also tensile tests were performed on the treated material to compare the mechanical properties of the fibres prior to pyrolysis and after decomposition. The results showed negative influence at the selected temperatures during the pyrolysis treatment on the mechanical properties of the carbon fibres.


A study review of aging polymer composite materials (PCM) under different heat-moisture conditions or water exposure with the sequential or parallel influence of static or cyclic loads in laboratory conditions is presented. The influence of tension and bending loads is compared. Conditions of the different load influence on parameters of carbon-reinforced plastics and glass-reinforced plastics are discussed. Equipment and units for climatic tests of PCM under loading are described. Simulation examples of indices of mechanical properties of PCM under the influence of environment and loads are shown.


A study review of aging polymer composite materials (PCM) under different heat-moisture conditions or water exposure with the sequential or parallel influence of static or cyclic loads in laboratory conditions is presented. The influence of tension and bending loads is compared. Conditions of the different load influence on parameters of carbon-reinforced plastics and glass-reinforced plastics are discussed. Equipment and units for climatic tests of PCM under loading are described. Simulation examples of indices of mechanical properties of PCM under the influence of environment and loads are shown.


Author(s):  
Georgel MIHU ◽  
Claudia Veronica UNGUREANU ◽  
Vasile BRIA ◽  
Marina BUNEA ◽  
Rodica CHIHAI PEȚU ◽  
...  

Epoxy resins have been presenting a lot of scientific and technical interests and organic modified epoxy resins have recently receiving a great deal of attention. For obtaining the composite materials with good mechanical proprieties, a large variety of organic modification agents were used. For this study gluten and gelatin had been used as modifying agents thinking that their dispersion inside the polymer could increase the polymer biocompatibility. Equal amounts of the proteins were milled together and the obtained compound was used to form 1 to 5% weight ratios organic agents modified epoxy materials. To highlight the effect of these proteins in epoxy matrix mechanical tests as three-point bending and compression were performed.


Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1128
Author(s):  
Sylwia Członka ◽  
Anna Strąkowska ◽  
Agnė Kairytė

In this study, coir fibers were successfully modified with henna (derived from the Lawsonia inermis plant) using a high-energy ball-milling process. In the next step, such developed filler was used as a reinforcing filler in the production of rigid polyurethane (PUR) foams. The impact of 1, 2, and 5 wt % of coir-fiber filler on structural and physico-mechanical properties was evaluated. Among all modified series of PUR composites, the greatest improvement in physico-mechanical performances was observed for PUR composites reinforced with 1 wt % of the coir-fiber filler. For example, on the addition of 1 wt % of coir-fiber filler, the compression strength was improved by 23%, while the flexural strength increased by 9%. Similar dependence was observed in the case of dynamic-mechanical properties—on the addition of 1 wt % of the filler, the value of glass transition temperature increased from 149 °C to 178 °C, while the value of storage modulus increased by ~80%. It was found that PUR composites reinforced with coir-fiber filler were characterized by better mechanical performances after the UV-aging.


Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 776
Author(s):  
Sixiang Zhai ◽  
Qingying Liu ◽  
Yuelong Zhao ◽  
Hui Sun ◽  
Biao Yang ◽  
...  

With the depletion of petroleum energy, the possibility of prices of petroleum-based materials increasing, and increased environmental awareness, biodegradable materials as a kind of green alternative have attracted more and more research attention. In this context, poly (lactic acid) has shown a unique combination of properties such as nontoxicity, biodegradability, biocompatibility, and good workability. However, examples of its known drawbacks include poor tensile strength, low elongation at break, poor thermal properties, and low crystallization rate. Lignocellulosic materials such as lignin and cellulose have excellent biodegradability and mechanical properties. Compounding such biomass components with poly (lactic acid) is expected to prepare green composite materials with improved properties of poly (lactic acid). This paper is aimed at summarizing the research progress of modification of poly (lactic acid) with lignin and cellulose made in in recent years, with emphasis on effects of lignin and cellulose on mechanical properties, thermal stability and crystallinity on poly (lactic acid) composite materials. Development of poly (lactic acid) composite materials in this respect is forecasted.


Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2636
Author(s):  
Petr Valášek ◽  
Miroslav Müller ◽  
Vladimír Šleger ◽  
Viktor Kolář ◽  
Monika Hromasová ◽  
...  

Composite materials with natural fillers have been increasingly used as an alternative to synthetically produced materials. This trend is visible from a representation of polymeric composites with natural cellulose fibers in the automotive industry of the European Union. This trend is entirely logical, owing to a preference for renewable resources. The experimental program itself follows pronounced hypotheses and focuses on a description of the mechanical properties of untreated and alkali-treated natural vegetable fibers, coconut and abaca fibers. These fibers have great potential for use in composite materials. The results and discussion sections contribute to an introduction of an individual methodology for mechanical property assessment of cellulose fibers, and allows for a clear definition of an optimal process of alkalization dependent on the content of hemicellulose and lignin in vegetable fibers. The aim of this research was to investigate the influence of alkali treatment on the surface microstructure and tensile properties of coir and abaca fibers. These fibers were immersed into a 5% solution of NaOH at laboratory temperature for a time interval of 30 min, 1 h, 2 h, 3 h, 6 h, 12 h, 24 h, and 48 h, rinsed and dried. The fiber surface microstructures before and after the alkali treatment were evaluated by SEM (scanning electron microscopy). SEM analysis showed that the alkali treatment in the NaOH solution led to a gradual connective material removal from the fiber surface. The effect of the alkali is evident from the visible changes on the surface of the fibers.


Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1369
Author(s):  
Sanjeev Kumar ◽  
Lalta Prasad ◽  
Vinay Kumar Patel ◽  
Virendra Kumar ◽  
Anil Kumar ◽  
...  

In recent times, demand for light weight and high strength materials fabricated from natural fibres has increased tremendously. The use of natural fibres has rapidly increased due to their high availability, low density, and renewable capability over synthetic fibre. Natural leaf fibres are easy to extract from the plant (retting process is easy), which offers high stiffness, less energy consumption, less health risk, environment friendly, and better insulation property than the synthetic fibre-based composite. Natural leaf fibre composites have low machining wear with low cost and excellent performance in engineering applications, and hence established as superior reinforcing materials compared to other plant fibres. In this review, the physical and mechanical properties of different natural leaf fibre-based composites are addressed. The influences of fibre loading and fibre length on mechanical properties are discussed for different matrices-based composite materials. The surface modifications of natural fibre also play a crucial role in improving physical and mechanical properties regarding composite materials due to improved fibre/matrix adhesion. Additionally, the present review also deals with the effect of silane-treated leaf fibre-reinforced thermoset composite, which play an important role in enhancing the mechanical and physical properties of the composites.


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