Avaliação das propriedades mecânicas de filmes biodegradáveis e sua aplicação em embalagens para acondicionamento de plantas

Neste trabalho empregou-se a técnica de casting para a produção de filmes. Utilizou-se quantidades distintas de amido de milho, glicerina e extrato de própolis-verde, sendo avaliadas as propriedades mecânicas (módulo de Young, elasticidade e tensão à ruptura) dos materiais obtidos. Verificou-se o efeito das variáveis e de suas interações pelo gráfico de Pareto. Superfícies de resposta foram construídas em testes conduzidos com 95% de confiança. A análise dos resultados indicou que o amido de milho foi o que mais influenciou na determinação do módulo de Young. Por outro lado, para a elongação, a glicerina, utilizada como agente plastificante, foi o fator mais relevante. Na análise da tensão à ruptura, observou-se que a interação entre a glicerina e o extrato de própolis-verde foi a mais significativa. Foi então selecionado o filme que apresentou as características mais adequadas no acondicionamento de mudas de alface. Os resultados indicaram que a amostra produzida a partir de 4 g de amido de milho, 1 g de glicerina e 0,12 g de extrato de própolis-verde foi a mais apropriada. Com relação ao acondicionamento da muda de alface, foi feita uma análise visual e macroscópica com a finalidade de verificar a resistência do filme biodegradável quando o substrato e a muda foram adicionados na embalagem. Foi observado que o material sintetizado e escolhido teve uma capacidade adequada para a sua retenção, o que favorece e ratifica o seu emprego, uma vez que, ao ser biodegradável, pode se tornar substituto de plásticos convencionais. Palavras-chave: Técnica casting. Módulo de Young. Elasticidade. Tensão à ruptura. Evaluation of the mechanical properties of biodegradable films and their application in packaging for packaging plants Abstract In this work the technique of casting was used for the production of films. Different quantities of corn starch, glycerin and propolis-green extract were used, and the mechanical properties (Young's modulus, elasticity and tensile strength) of the materials obtained were evaluated. The effect of the variables and their interactions on the Pareto graph was verified. Response surfaces were constructed in tests conducted with 95% confidence. The analysis of the results indicated that the corn starch was the most influential in determining the Young's modulus. On the other hand, for elongation, glycerin, used as a plasticizing agent, was the most relevant factor. In analyzing the rupture stress, it was observed that the interaction between glycerin and the propolis-green extract was the most significant. It wasthenselectedthefilmthatpresentedthemost suitable characteristics in the packaging of lettuce seedlings. The results indicated that the sample produced from 4 g of cornstarch, 1 g of glycerin and 0.12 g of propolis-green extract was the most appropriate. Regarding the conditioning of the lettuce change, a visual and macroscopic analysis was performed to verify the resistance of the biodegradable film when the substrate and the change were added to the packaging. It hás been observed that the synthesized and selected material hás the proper capacity for its retention, which favors and ratifies its use, since, being biodegradable, it can be come a substitute for conventional plastics. Keywords:Casting technique. Young's module. Elasticity. Tensionto break.

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Influence of cellulose fibers on physicochemical properties of biodegradable films based on polysaccharide derivatives

Open Agriculture ◽

10.1515/opag-2020-0046 ◽

2020 ◽

Vol 5 (1) ◽

pp. 462-465

Author(s):

Adrian K. Antosik ◽

Katarzyna Wilpiszewska

Keyword(s):

Mechanical Properties ◽

Citric Acid ◽

Physicochemical Properties ◽

Young’S Modulus ◽

Water Solubility ◽

Filler Content ◽

Young's Modulus ◽

Cellulose Fibers ◽

Biodegradable Films ◽

Polysaccharide Derivatives

AbstractThe article presents a method of obtaining films based on carboxymethyl polysaccharide derivatives cross-linked with citric acid and reinforced with cellulose fibers (CFs). The addition of CFs to a film improves the mechanical properties of the composite. With the increase of filler content, the water solubility drops from 64 to 61%, respectively, for a system without a filler and that containing 7 wt% CFs, whereas Young’s modulus increases from 4.8 to 24.8 MPa for a film containing 5 wt% filler.

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Mechanical properties of FeAlSi powders prepared by mechanical alloying from different initial feedstock materials

Matériaux & Techniques ◽

10.1051/mattech/2018063 ◽

2019 ◽

Vol 107 (2) ◽

pp. 207 ◽

Cited By ~ 2

Author(s):

Jaroslav Čech ◽

Petr Haušild ◽

Miroslav Karlík ◽

Veronika Kadlecová ◽

Jiří Čapek ◽

...

Keyword(s):

Mechanical Properties ◽

Mechanical Alloying ◽

Young’S Modulus ◽

Milling Time ◽

Young's Modulus ◽

Element Model ◽

X Ray Diffraction ◽

X Ray ◽

Powder Particles ◽

Complete Homogenization

FeAl20Si20 (wt.%) powders prepared by mechanical alloying from different initial feedstock materials (Fe, Al, Si, FeAl27) were investigated in this study. Scanning electron microscopy, X-ray diffraction and nanoindentation techniques were used to analyze microstructure, phase composition and mechanical properties (hardness and Young’s modulus). Finite element model was developed to account for the decrease in measured values of mechanical properties of powder particles with increasing penetration depth caused by surrounding soft resin used for embedding powder particles. Progressive homogenization of the powders’ microstructure and an increase of hardness and Young’s modulus with milling time were observed and the time for complete homogenization was estimated.

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First principles computation of composition dependent elastic constants of omega in titanium alloys: implications on mechanical behavior

Scientific Reports ◽

10.1038/s41598-021-91594-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

R. Salloom ◽

S. A. Mantri ◽

R. Banerjee ◽

S. G. Srinivasan

Keyword(s):

Mechanical Properties ◽

Young’S Modulus ◽

First Principles ◽

Young's Modulus ◽

Group Vi ◽

Group V ◽

Β Phase ◽

Ti Alloys ◽

Ω Phase ◽

Stabilizer Concentration

AbstractFor decades the poor mechanical properties of Ti alloys were attributed to the intrinsic brittleness of the hexagonal ω-phase that has fewer than 5-independent slip systems. We contradict this conventional wisdom by coupling first-principles and cluster expansion calculations with experiments. We show that the elastic properties of the ω-phase can be systematically varied as a function of its composition to enhance both the ductility and strength of the Ti-alloy. Studies with five prototypical β-stabilizer solutes (Nb, Ta, V, Mo, and W) show that increasing β-stabilizer concentration destabilizes the ω-phase, in agreement with experiments. The Young’s modulus of ω-phase also decreased at larger concentration of β-stabilizers. Within the region of ω-phase stability, addition of Nb, Ta, and V (Group-V elements) decreased Young’s modulus more steeply compared to Mo and W (Group-VI elements) additions. The higher values of Young’s modulus of Ti–W and Ti–Mo binaries is related to the stronger stabilization of ω-phase due to the higher number of valence electrons. Density of states (DOS) calculations also revealed a stronger covalent bonding in the ω-phase compared to a metallic bonding in β-phase, and indicate that alloying is a promising route to enhance the ω-phase’s ductility. Overall, the mechanical properties of ω-phase predicted by our calculations agree well with the available experiments. Importantly, our study reveals that ω precipitates are not intrinsically embrittling and detrimental, and that we can create Ti-alloys with both good ductility and strength by tailoring ω precipitates' composition instead of completely eliminating them.

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Tailoring a Low Young Modulus for a Beta Titanium Alloy by Combining Severe Plastic Deformation with Solution Treatment

Materials ◽

10.3390/ma14133467 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3467

Author(s):

Anna Nocivin ◽

Doina Raducanu ◽

Bogdan Vasile ◽

Corneliu Trisca-Rusu ◽

Elisabeta Mirela Cojocaru ◽

...

Keyword(s):

Electron Microscopy ◽

Mechanical Properties ◽

Plastic Deformation ◽

Severe Plastic Deformation ◽

Young’S Modulus ◽

Young's Modulus ◽

Solution Treatment ◽

Young Modulus ◽

Orthopedic Implants ◽

Beta Titanium Alloy

The present paper analyzed the microstructural characteristics and the mechanical properties of a Ti–Nb–Zr–Fe–O alloy of β-Ti type obtained by combining severe plastic deformation (SPD), for which the total reduction was of etot = 90%, with two variants of super-transus solution treatment (ST). The objective was to obtain a low Young’s modulus with sufficient high strength in purpose to use the alloy as a biomaterial for orthopedic implants. The microstructure analysis was conducted through X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) investigations. The analyzed mechanical properties reveal promising values for yield strength (YS) and ultimate tensile strength (UTS) of about 770 and 1100 MPa, respectively, with a low value of Young’s modulus of about 48–49 GPa. The conclusion is that satisfactory mechanical properties for this type of alloy can be obtained if considering a proper combination of SPD + ST parameters and a suitable content of β-stabilizing alloying elements, especially the Zr/Nb ratio.

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Phase Formation, Microstructure and Mechanical Properties of Mg67Ag33 as Potential Biomaterial

Metals ◽

10.3390/met11030461 ◽

2021 ◽

Vol 11 (3) ◽

pp. 461

Author(s):

Konrad Kosiba ◽

Konda Gokuldoss Prashanth ◽

Sergio Scudino

Keyword(s):

Mechanical Properties ◽

Young’S Modulus ◽

Young's Modulus ◽

Equilibrium Phase ◽

Antibacterial Properties ◽

Equilibrium Phase Diagram ◽

Compressive Yield Strength ◽

X Ray ◽

Fine Grained ◽

Equilibrium Phases

The phase and microstructure formation as well as mechanical properties of the rapidly solidified Mg67Ag33 (at. %) alloy were investigated. Owing to kinetic constraints effective during rapid cooling, the formation of equilibrium phases is suppressed. Instead, the microstructure is mainly composed of oversaturated hexagonal closest packed Mg-based dendrites surrounded by a mixture of phases, as probed by X-ray diffraction, electron microscopy and energy dispersive X-ray spectroscopy. A possible non-equilibrium phase diagram is suggested. Mainly because of the fine-grained dendritic and interdendritic microstructure, the material shows appreciable mechanical properties, such as a compressive yield strength and Young’s modulus of 245 ± 5 MPa and 63 ± 2 GPa, respectively. Due to this low Young’s modulus, the Mg67Ag33 alloy has potential for usage as biomaterial and challenges ahead, such as biomechanical compatibility, biodegradability and antibacterial properties are outlined.

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Effect of Nanopores on Mechanical Properties of the Shape Memory Alloy

Micromachines ◽

10.3390/mi12050529 ◽

2021 ◽

Vol 12 (5) ◽

pp. 529

Author(s):

Chunzhi Du ◽

Zhifan Li ◽

Bingfei Liu

Keyword(s):

Mechanical Properties ◽

Constitutive Model ◽

Shape Memory ◽

Young’S Modulus ◽

Residual Strain ◽

Surface Effect ◽

Young's Modulus ◽

Strain Curve ◽

Stress Strain ◽

Strength Limit

Nanoporous Shape Memory Alloys (SMA) are widely used in aerospace, military industry, medical and health and other fields. More and more attention has been paid to its mechanical properties. In particular, when the size of the pores is reduced to the nanometer level, the effect of the surface effect of the nanoporous material on the mechanical properties of the SMA will increase sharply, and the residual strain of the SMA material will change with the nanoporosity. In this work, the expression of Young’s modulus of nanopore SMA considering surface effects is first derived, which is a function of nanoporosity and nanopore size. Based on the obtained Young’s modulus, a constitutive model of nanoporous SMA considering residual strain is established. Then, the stress–strain curve of dense SMA based on the new constitutive model is drawn by numerical method. The results are in good agreement with the simulation results in the published literature. Finally, the stress-strain curves of SMA with different nanoporosities are drawn, and it is concluded that the Young’s modulus and strength limit decrease with the increase of nanoporosity.

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Effect of Castor Oil Impregnation on the Physical and Mechanical Properties of Bacterial Cellulose

Polymers from Renewable Resources ◽

10.1177/204124791200300102 ◽

2012 ◽

Vol 3 (1) ◽

pp. 13-26

Author(s):

Myrtha Karina ◽

Lucia Indrarti ◽

Rike Yudianti ◽

Indriyati

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Bacterial Cellulose ◽

Young’S Modulus ◽

Castor Oil ◽

Young's Modulus ◽

Physical And Mechanical Properties ◽

Scanning Electron Micrographs ◽

Elongation At Break ◽

Acetone Water

The effect of castor oil on the physical and mechanical properties of bacterial cellulose is described. Bacterial cellulose (BC) was impregnated with 0.5–2% (w/v) castor oil (CO) in acetone–water, providing BCCO films. Scanning electron micrographs revealed that the castor oil penetrated the pores of the bacterial cellulose, resulting in a smoother morphology and enhanced hydrophilicity. Castor oil caused a slight change in crystallinity indices and resulted in reduced tensile strength and Young's modulus but increased elongation at break. A significant reduction in tensile strength and Young's modulus was achieved in BCCO films with 2% castor oil, and there was an improvement in elongation at break and hydrophilicity. Impregnation with castor oil, a biodegradable and safe plasticiser, resulted in less rigid and more ductile composites.

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Mechanical Properties of Pyrolytic "SiOCN" Thin Coatings

MRS Proceedings ◽

10.1557/proc-308-577 ◽

1993 ◽

Vol 308 ◽

Cited By ~ 1

Author(s):

Sandrine Bec ◽

André Tonck ◽

Jean-Luc Loubet

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Young’S Modulus ◽

Young's Modulus ◽

Ceramic Coatings ◽

Optical Observation ◽

Thin Coatings ◽

Polymer Precursors ◽

Polymeric State

ABSTRACTPyrolysis of polymer precursors (polysilazane) is a technologically and economically interesting way to produce thin ceramic coatings. However, many cracks appear and decohesion occurs during pyrolysis when the ceramic coatings (SiOCN) are thicker than 0.5 micrometers. In order to understand these cracking phenomena, the coatings are mechanically characterized by nanoindentation at different stages of the pyrolysis heat treatment.During pyrolysis, the cracking temperature is detected by in-situ optical observation. The thickness of the coatings varies during pyrolysis from 3 micrometers at the polymeric state to 1 micrometer at the ceramic state. The coatings' properties, hardness and Young's modulus are evaluated after heat treatment, taking into account the substrate's influence. A large variation of these properties occurs at the cracking temperature. Both the hardness and the Young's modulus are multiplied by a factor of 10. By analysing these results, we show that cracking is correlated with the evolution of the coatings' mechanical properties during the transformation.

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Atomic Simulations of Packing Structures, Local Stress and Mechanical Properties for One Silicon Lattice with Single Vacancy on Heating

Materials ◽

10.3390/ma14113127 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3127

Author(s):

Feng Dai ◽

Dandan Zhao ◽

Lin Zhang

Keyword(s):

Mechanical Properties ◽

Young’S Modulus ◽

Young's Modulus ◽

Silicon Crystal ◽

Local Stress ◽

Uniaxial Tensile ◽

Single Vacancy ◽

Vacancy Defects ◽

Silicon Lattice ◽

Atomic Simulations

The effect of vacancy defects on the structure and mechanical properties of semiconductor silicon materials is of great significance to the development of novel microelectronic materials and the processes of semiconductor sensors. In this paper, molecular dynamics is used to simulate the atomic packing structure, local stress evolution and mechanical properties of a perfect lattice and silicon crystal with a single vacancy defect on heating. In addition, their influences on the change in Young’s modulus are also analyzed. The atomic simulations show that in the lower temperature range, the existence of vacancy defects reduces the Young’s modulus of the silicon lattice. With the increase in temperature, the local stress distribution of the atoms in the lattice changes due to the migration of the vacancy. At high temperatures, the Young’s modulus of the silicon lattice changes in anisotropic patterns. For the lattice with the vacancy, when the temperature is higher than 1500 K, the number and degree of distortion in the lattice increase significantly, the obvious single vacancy and its adjacent atoms contracting inward structure disappears and the defects in the lattice present complex patterns. By applying uniaxial tensile force, it can be found that the temperature has a significant effect on the elasticity–plasticity behaviors of the Si lattice with the vacancy.

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Mechanical properties and toughening mechanisms of epoxy/graphene nanocomposites

Journal of Polymer Engineering ◽

10.1515/polyeng-2014-0134 ◽

2015 ◽

Vol 35 (3) ◽

pp. 257-266 ◽

Cited By ~ 10

Author(s):

Rahim Eqra ◽

Kamal Janghorban ◽

Habib Daneshmanesh

Keyword(s):

Mechanical Properties ◽

Fracture Surface ◽

Flexural Strength ◽

Young’S Modulus ◽

Young's Modulus ◽

Graphene Nanosheets ◽

Flexural Modulus ◽

Mechanical Tests ◽

Toughening Mechanism ◽

Graphene Nanocomposites

Abstract Because of extraordinary physical, chemical and mechanical properties, graphene nanosheets (GNS) are suitable fillers for optimizing the properties of different polymers. In this research, the effect of GNS content (up to 1 wt.%) on tensile and flexural properties, morphology of fracture surface, and toughening mechanism of epoxy were investigated. Results of mechanical tests showed a peak for tensile and flexural strength of samples with 0.1 wt.% GNS such that the tensile and flexural strength improved by 13% and 3.3%, respectively. The Young’s modulus and flexural modulus increased linearly with GNS content, although the behavior of the Young’s modulus was more remarkable. Morphological investigations confirmed this behavior because the GNS dispersion in the epoxy matrix was uniform at lower contents and agglomerated at higher contents. Finally, microscopical observation showed that the major toughening mechanism of graphene-epoxy nanocomposites was crack path deflection, which changed the mirror fracture surface of the pure epoxy to rough surface.

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