scholarly journals PVA/Polysaccharides Blended Films: Mechanical Properties

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Fábio E. F. Silva ◽  
Maria Carolina B. Di-Medeiros ◽  
Karla A. Batista ◽  
Kátia F. Fernandes

Blends of polyvinyl alcohol (PVA) and angico gum (AG) and/or cashew gum (CG) were used to produce films by casting method. Morphological and mechanical properties of these films were studied and compared to the properties of a commercial collagen membrane of bovine origin (MBO). The films presented thickness varying from 70 to 140 μm (PVA/AG) and 140 to 200 μm (PVA/CG). Macroscopic analysis showed that a PVA/CG film was very similar to MBO regarding the color and transparency. The higher values of tensile strength (TS) and elastic modulus (EM) were observed in the film. On the other hand, PVA/CG and PVA/CG-AG presented the highest value of percentage of elongation (E%). Pearson’s Correlation Analysis revealed a positive correlation between TS and EM and a negative correlation between E% and EM. The PVA/CG film presented mechanical properties very similar to MBO, with the advantage of a higher E% (11.96) than MBO (2.94). The properties of the PVA blended films depended on the polysaccharide added in the blend, as well as the acid used as a catalyst. However, all produced films presented interesting mechanical characteristics which enables several biotechnological applications.

2019 ◽  
Vol 14 (29) ◽  
pp. 107-124
Author(s):  
Nahida J. Hameed

The work concerned with studying the effect of (SiO2) addition as afiller on the adhesive properties of (PVA). Samples were prepared assheets by using casting method. The mechanical properties showedthat increase in tensile strength from (34MPa) to (68MPa) when(SiO2) added to (PVA). The adhesive strength showed that jointproperties depend upon specific adhesive characteristic of material(PVA) and (SiO2\PVA)composites at different concentrations (1.5%,2.5%, 3.5%, 4.5wt%), the cohesive strength of the adhesive material,the joint design, and adherent type (Sponge Rubber(SR), Naturalleather (NL), Vulcanized Rubber(VR), and Cartoon). The resultsproved the tensile strength increased with (SiO2) ratio, so it can beused as the adhesive material. Shear strength showed an increasewith (SiO2) ratio of sponge rubber, and cartoon adherent, whereas itwas increased up to 2.5% for Natural Leather, and VulcanizedRubber then decreased; That suggested it is most suitable for spongerubber adhesive and cartoon than the other adherents.


1959 ◽  
Vol 32 (3) ◽  
pp. 662-667 ◽  
Author(s):  
E. V. Kuvshinskiĭ ◽  
E. A. Sidorovich

Abstract It is a known fact that the mechanical properties of rubber depend essentially upon the density (i.e., the crosslink density) of the vulcanization network. The dependence of the “equilibrium” (statistical) modulus of elasticity upon the concentration of crosslinks as well as the dependence of the tensile strength —has been studied in a series of investigations. In contrast to this, analogous investigations of the dynamic mechanical characteristics are practically nonexistent. We have undertaken our present work with the hope of filling this gap. Series of gum compounds were prepared from natural (smoked sheet) and synthetic polyisoprene (SKI), sodium butadiene (SKB), butadiene-styrene (SKS-30A), and butadiene-nitrile (SKN-26) rubbers which varied in their degree of vulcanization. The percentage of sulfur and accelerator were varied as were the temperature and the time of vulcanization. The mechanical-dynamic characteristics of the rubber at a predetermined impact pressure—the rebound elasticity and the dynamic elastic modulus were studied with the pendulum elastometer KS over a temperature range of 20–100° C. The duration of the stress was .03/.05 second. We estimated the concentration of crosslinks in the rubber samples from the magnitude of the equilibrium modulus. In order to determine this characteristic, we compressed specimens which were 20 mm in height and 10 mm in diameter 15% and studied the relaxation of stress. The specimens were also tested on the pendulum elastometer. Heppler's consistometer operating on the lever weight principle, was adapted for our measurements. The experiments were conducted at 60° C, the thermostatic control being effected with the help of Heppler's ultrathermostat.


2020 ◽  
Vol 38 (1) ◽  
pp. 34-40
Author(s):  
B. Yavuzer ◽  
D. Özyürek ◽  
T. Tunçay

AbstractThis study investigates microstructures and mechanical properties of the alloys obtained by adding Cu (0.7 % and 0.9 %) and Al (0.7 % and 0.9 %) to lead-free Sn-9Zn eutectic soldering alloy produced by investment casting method. The results show that Cu5Zn8 phase has formed in the structure of Cu added alloys and the Al2O3 phase has formed due to addition of Al. It was found that small and round-shaped Al2O3 phase increased the tensile strength of the new alloy compared to the eutectic alloy. In addition, it was observed that the microhardness of Cu added alloys was lower than that of Sn-9Zn eutectic alloy, but the microhardness of alloys containing Al was higher compared to the other eutectic Sn-9Zn alloy.


Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5042
Author(s):  
Jaeyoung Kwon ◽  
Junhyeok Ock ◽  
Namkug Kim

3D printing technology has been extensively applied in the medical field, but the ability to replicate tissues that experience significant loads and undergo substantial deformation, such as the aorta, remains elusive. Therefore, this study proposed a method to imitate the mechanical characteristics of the aortic wall by 3D printing embedded patterns and combining two materials with different physical properties. First, we determined the mechanical properties of the selected base materials (Agilus and Dragonskin 30) and pattern materials (VeroCyan and TPU 95A) and performed tensile testing. Three patterns were designed and embedded in printed Agilus–VeroCyan and Dragonskin 30–TPU 95A specimens. Tensile tests were then performed on the printed specimens, and the stress-strain curves were evaluated. The samples with one of the two tested orthotropic patterns exceeded the tensile strength and strain properties of a human aorta. Specifically, a tensile strength of 2.15 ± 0.15 MPa and strain at breaking of 3.18 ± 0.05 mm/mm were measured in the study; the human aorta is considered to have tensile strength and strain at breaking of 2.0–3.0 MPa and 2.0–2.3 mm/mm, respectively. These findings indicate the potential for developing more representative aortic phantoms based on the approach in this study.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sekar Sanjeevi ◽  
Vigneshwaran Shanmugam ◽  
Suresh Kumar ◽  
Velmurugan Ganesan ◽  
Gabriel Sas ◽  
...  

AbstractThis investigation is carried out to understand the effects of water absorption on the mechanical properties of hybrid phenol formaldehyde (PF) composite fabricated with Areca Fine Fibres (AFFs) and Calotropis Gigantea Fibre (CGF). Hybrid CGF/AFF/PF composites were manufactured using the hand layup technique at varying weight percentages of fibre reinforcement (25, 35 and 45%). Hybrid composite having 35 wt.% showed better mechanical properties (tensile strength ca. 59 MPa, flexural strength ca. 73 MPa and impact strength 1.43 kJ/m2) under wet and dry conditions as compared to the other hybrid composites. In general, the inclusion of the fibres enhanced the mechanical properties of neat PF. Increase in the fibre content increased the water absorption, however, after 120 h of immersion, all the composites attained an equilibrium state.


Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 548 ◽  
Author(s):  
Leonid Agureev ◽  
Valeriy Kostikov ◽  
Zhanna Eremeeva ◽  
Svetlana Savushkina ◽  
Boris Ivanov ◽  
...  

The article presents the study of alumina nanoparticles’ (nanofibers) concentration effect on the strength properties of pure nickel. The samples were obtained by spark plasma sintering of previously mechanically activated metal powders. The dependence of the grain size and the relative density of compacts on the number of nanofibers was investigated. It was found that with an increase in the concentration of nanofibers, the average size of the matrix particles decreased. The effects of the nanoparticle concentration (0.01–0.1 wt.%) on the elastic modulus and tensile strength were determined for materials at 25 °C, 400 °C, and 750 °C. It was shown that with an increase in the concentration of nanofibers, a 10–40% increase in the elastic modulus and ultimate tensile strength occurred. A comparison of the mechanical properties of nickel in a wide range of temperatures, obtained in this work with materials made by various technologies, is carried out. A description of nanofibers’ mechanisms of influence on the structure and mechanical properties of nickel is given. The possible impact of impurity phases on the properties of nickel is estimated. The tendency of changes in the mechanical properties of nickel, depending on the concentration of nanofibers, is shown.


2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Haoliang Huang ◽  
Guang Ye

In this research, self-healing due to further hydration of unhydrated cement particles is taken as an example for investigating the effects of capsules on the self-healing efficiency and mechanical properties of cementitious materials. The efficiency of supply of water by using capsules as a function of capsule dosages and sizes was determined numerically. By knowing the amount of water supplied via capsules, the efficiency of self-healing due to further hydration of unhydrated cement was quantified. In addition, the impact of capsules on mechanical properties was investigated numerically. The amount of released water increases with the dosage of capsules at different slops as the size of capsules varies. Concerning the best efficiency of self-healing, the optimizing size of capsules is 6.5 mm for capsule dosages of 3%, 5%, and 7%, respectively. Both elastic modulus and tensile strength of cementitious materials decrease with the increase of capsule. The decreasing tendency of tensile strength is larger than that of elastic modulus. However, it was found that the increase of positive effect (the capacity of inducing self-healing) of capsules is larger than that of negative effects (decreasing mechanical properties) when the dosage of capsules increases.


2015 ◽  
Vol 799-800 ◽  
pp. 115-119 ◽  
Author(s):  
Anika Zafiah M. Rus ◽  
Nur Munirah Abdullah ◽  
M.F.L. Abdullah ◽  
M. Izzul Faiz Idris

Graphite reinforced bio-based epoxy composites with different particulate fractions of graphite were investigated for mechanical properties such as tensile strength, elastic modulus and elongation at break. The graphite content was varied from 5 wt.%, 10 wt.%, 15 wt.%, 20 wt.%, 25 wt.%, 30 wt.% by weight percent in the composites. The results showed that the mechanical properties of the composites mainly depend on dispersion condition of the treated graphite filler, aggregate structure and strong interfacial bonding between treated graphite in the bio-based epoxy matrix. The composites showed improved tensile strength and elastic modulus with increase treated graphite weight loading. This also revealed the composites with increasing filler content was decreasing the elongation at break.


2010 ◽  
Vol 97-101 ◽  
pp. 814-817 ◽  
Author(s):  
Jun Deng

One of the greatest drawbacks to predicting the behaviour of bonded joints has been the lack of reliable data on the mechanical properties of adhesives. In this study, methods for determining mechanical properties of structural adhesive were discussed. The Young’s modulus, Poisson’s ratio and tensile strength of the adhesive were tested by dogbone specimens (bulk form) and butt joint specimens (in situ form). The shear modulus and shear strength were test by V-notched specimens (bulk form) and thick adherend lap-shear (TALS) joint specimens (in situ form). The test results show that the elastic modulus provided by the manufacturer is too low, the dogbone specimen is better than the butt joint specimen to test the tensile strength and elastic modulus and the TALS joint specimen is better than the V-notched specimen to test the shear strength.


2021 ◽  
Vol 887 ◽  
pp. 110-115
Author(s):  
G.A. Sabirova ◽  
R.R. Safin ◽  
N.R. Galyavetdinov

This paper presents the findings of experimental studies of the physical and mechanical properties of wood-filled composites based on polylactide (PLA) and vegetable filler in the form of wood flour (WF) thermally modified at 200-240 °C. It also reveals the dependence of the tensile strength, impact strength, bending elastic modulus, and density of composites on the amount of wood filler and the temperature of its thermal pre-modification. We established that an increase in the concentration of the introduced filler and the degree of its heat treatment results in a decrease of the tensile strength, impact strength and density of composite materials, while with a lower binder content, thermal modification at 200 °C has a positive effect on bending elastic modulus. We also found that 40 % content of a wood filler heated to 200 °C is sufficient to maintain relatively high physical and mechanical properties of composite materials. With a higher content of a wood filler, the cost can be reduced but the quality of products made of this material may significantly deteriorate. However, depending on the application and the life cycle of this product, it is possible to develop a formulation that includes a high concentration of filler.


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