scholarly journals Utilization of Recycled Thermoplastic Nylon Combined with Virgin Nylon and the Effect on its Mechanical Properties as a Denture Base Material

2019 ◽  
pp. 51-55
Author(s):  
Haslinda Z Tamin ◽  
Siti Wahyuni ◽  
Ismet Danial Nasution
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Modulus Of Elasticity ◽  
Statistical Significance ◽  
Testing Machine ◽  
Base Material ◽  
Bending Test ◽  
Laboratory Research ◽  
Compressive Yield Strength ◽  
Mechanical Degradation

The injection molding process of thermoplastic nylon produces nylon residues in the form of sprue. Nylon residues are non-biodegradable which causes serious ecological problems, hence recycling becomes a necessity. However, recycled nylon is subjected to thermal, oxidative, and mechanical degradation during process which may decrease the mechanical properties of recycled nylon. In order to overcome the decreased mechanical properties of recycled nylon, modification by combining recycled nylon with virgin nylon is considered. Aim: This study aimed to determine the effect of adding virgin nylon into recycled nylon on the modulus of elasticity and compressive yield strength. Settings and Design: Experimental laboratory research. Methods and Materials: A total of 45 samples were used. Samples were divided into 3 groups which include 100% virgin nylon as control (A), 100% recycled nylon (B) and combination of 60% virgin nylon with 40% recycled nylon (C). The samples were tested using Universal Testing Machine (Tensilon RTF, Japan) with three point bending test and compression test with the speed of 5mm/min with ultimate load. Statistical analysis used: The obtained results were analyzed using Univarian test, One-way ANOVA test and Turkey’s Honestly Significant Different test. Result: There was statistical significance in adding virgin nylon into recycled nylon on its mechanical properties, namely modulus of elasticity and compressive yield strength (p<0.05). Conclusion: The combination of 60% virgin nylon with 40% recycled nylon has better elastic modulus and compressive yield strength values compared to 100% recycled nylon.

scholarly journals Evaluation of the Effects of Fluoride Prophylactic Agents on Mechanical Properties of Nickel Titanium Wires using Scanning Electron Microscope

2018 ◽  
Vol 19 (3) ◽  
pp. 283-286
Author(s):  
Deepika Gupta ◽  
Amit K Gupta ◽  
Ajay K Gupta ◽  
Gita Shukla
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Yield Strength ◽  
Scanning Electron Microscope ◽  
Modulus Of Elasticity ◽  
Orthodontic Treatment ◽  
Nickel Titanium ◽  
Bending Test ◽  
Niti Wires ◽  
Scanning Electron

ABSTRACT Introduction Orthodontic treatment these days is increasing in demand, and therefore, it is relatively imperative for the orthodontist to prescribe the use of fluoride-containing products, such as mouthwashes and gels, to help prevent dental caries and maintain healthy oral health. The aim of the study was to assess and evaluate the effects of fluoride prophylactic agents on mechanical properties of nickel titanium (NiTi) wires during orthodontic treatment using scanning electron microscope (SEM). Materials and methods We used the commercially available round preformed NiTi orthodontic archwire (3M company) and three different mouthwash solutions, i.e., Phos-Flur gel (1.1% sodium acidulated phosphate fluoride, APF, 0.5% w/v fluoride, pH = 5.1; Colgate Oral Pharmaceuticals) and Prevident 5000 (1.1% sodium fluoride neutral agent, 0.5% w/v fluoride, pH = 7; Colgate Oral Pharmaceuticals). All the specimens were subjected to a three-point bending test on a universal testing machine. To observe the surface morphological changes, one wire from each group was randomly selected and observed under a SEM. Results It was observed that there was not much difference in the values of both modulus of elasticity and yield strength obtained after loading of stress on the wires in all the three experimental conditions. A significant difference in both modulus of elasticity and yield strength was observed during unloading of stress. Further, when the surface characteristics were observed for all the specimens using SEM images, it was observed that NiTi wires treated with Phos-Flur showed large surface defects which appeared as round, pitted areas depicting corrosion, numerous white inclusions, and overall damaged surface structure of the wire as compared with the control. Conclusion Thus, fluoridated mouthwashes are essential to maintain good oral hygiene and decrease instance of caries in patients undergoing orthodontic treatment. The prophylactic usage of topical fluoride agents on NiTi wire seems to diminish the mechanical properties of the orthodontic wire that could significantly affect future treatment outcomes. Clinical significance It has been proved that fluoride mouthwashes/gels do affect the structural surface qualities and strength of wires used during the orthodontic treatment irrespective of the composition of the wires. Therefore, it is the responsibility of the clinician to prescribe these prophylactic agents carefully while keeping in mind their pH so that the overall result of the treatment may not be hampered and delayed due to change in properties of the wires used. How to cite this article Gupta AK, Shukla G, Sharma P, Gupta AK, Kumar A, Gupta D. Evaluation of the Effects of Fluoride Prophylactic Agents on Mechanical Properties of Nickel Titanium Wires using Scanning Electron Microscope. J Contemp Dent Pract 2018;19(3):283-286.

Effect of Bubble Inclusions on the Mechanical Properties of Cast Poly-Methyl Metacrylate

1972 ◽  
Vol 94 (4) ◽  
pp. 847-852 ◽  
Author(s):  
J. D. Stachiw
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Loading Condition ◽  
Stress Raiser ◽  
Compressive Yield Strength ◽  
Compressive Test ◽  
Acrylic Plastic ◽  
Methyl Metacrylate ◽  
As Stress ◽  
Stress Raisers

Bubble inclusions present in cast acrylic plastic generally degrade the mechanical properties of the material. To evaluate the effect of bubbles on the mechanical strength of acrylic plastic, 120 tensile and compressive test specimens were machined from massive acrylic castings with bubble inclusions. The specimens were tested under uniaxial loading condition and effect of bubbles on tensile and compressive strength noted. The stress raiser effect of bubbles caused the tensile specimens to fail at stresses 7 to 30 percent lower than observed in specimens without bubbles. The compressive yield strength was not affected by bubbles. However, here the bubbles served as stress raisers also and caused cracks to initiate at the bubble surfaces when the yield strength of acrylic plastic was reached.

scholarly journals Effect of introduction of fullerene soot on mechanical properties of unidirectional thermoplastic tape

2018 ◽  
Vol 245 ◽  
pp. 04011 ◽  
Author(s):  
Ilya Kobykhno ◽  
Dmytro Honcharenko ◽  
Vladimir Yadykin ◽  
Oleg Stolyarov ◽  
Oleg Tolochko
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Carbon Fibers ◽  
Modulus Of Elasticity ◽  
Hot Pressing ◽  
Bending Test ◽  
Transverse Reinforcement ◽  
Fullerene Soot

A series of unidirectional thermoplastic tapes (UD tapes) specimens based on carbon fibers and polyamide filled with fullerene soot in a concentration of up to 4 wt. % was made. From the obtained tapes by the method of hot pressing, composite materials (CM) specimens with 0/0 and 90/90 ply orientations were made. A study of the mechanical properties of the samples obtained by the 3-point bending test was made. Shown that the introduction of fullerene soot up to 2 wt. % can significantly increase the strength and modulus of elasticity of both longitudinal and transverse reinforcement directions. Further increase in the concentration of soot leads to a decrease in properties. A theory that describes the effect of fullerene soot on the properties of CM, including the increase and further decrease in properties, depending on the concentration of nanoparticles was proposed.

scholarly journals Study on Dynamic Mechanical Properties and Constitutive Model Construction of TC18 Titanium Alloy

Metals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 44 ◽  
Author(s):  
Changming Zhang ◽  
Anle Mu ◽  
Yun Wang ◽  
Hui Zhang
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Flow Stress ◽  
Yield Strength ◽  
Constitutive Model ◽  
Testing Machine ◽  
Dynamic Mechanical Properties ◽  
Stress Strain ◽  
Dynamic Mechanical ◽  
Different Temperatures

In order to investigate the static and dynamic mechanical properties of TC18 titanium alloy, the quasi-static stress–strain curve of TC18 titanium alloy under room temperature was obtained by DNS 100 electronic universal testing machine (Changchun Institute of Mechanical Science Co., Ltd., Changchun, China). Meanwhile, the flow stress–strain curves under different temperatures and strain rates are analyzed by split Hopkinson pressure bar (SHPB) device with synchronous assembly system. On the basis of the two experimental data, the JC constitutive model under the combined action of high temperature and impact load is established using the linear least squares method. The results show the following: the yield strength and flow stress of TC18 titanium alloy increase slowly with the increase of the strain rate, and the strain value corresponding to the yield strength is reduced. With the increase of strain, the flow stress increases at first and then decreases at different temperatures. The strain value corresponding to the transition point rises with the temperature increase, and the corresponding stress value remains basically unchanged. With the increase of experimental temperature, the flow stress shows a downward trend, and the JC constitutive model can predict the plastic flow stress well.

scholarly journals A Study on Fiber Laser Welding of High-Manganese Steel for Cryogenic Tanks

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1536
Author(s):  
Jaewoong Kim ◽  
Jisun Kim ◽  
Changmin Pyo
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Yield Strength ◽  
Laser Welding ◽  
Base Material ◽  
Manganese Steel ◽  
High Manganese ◽  
Fiber Laser Welding ◽  
High Manganese Steel ◽  
Welding Part

As the environmental regulations on ship emissions by the International Maritime Organization (IMO) become stricter, the demand for a ship powered by liquefied natural gas (LNG) is rapidly increasing worldwide. Compared to other materials, high-manganese steel has the advantages of superior impact toughness at cryogenic temperatures, a low thermal expansion coefficient, and a low-cost base material and welding rod. However, there is a limitation that the mechanical properties of a filler material are worse than those of a base material that has excellent mechanical properties. To solve these shortcomings, a basic study was performed to apply fiber laser welding with little welding deformation and no filler material to high-manganese steel. The relationship between laser welding parameters and penetration shapes was confirmed through cross-section observation and analysis by performing a bead on plate (BOP) test by changing laser power and welding speed, which are the main parameters of laser welding. In addition, the welding performance was evaluated through mechanical property tests (yield strength, tensile strength, hardness, cryogenic impact strength) of a welding part after performing the high-manganese steel laser butt welding experiment. As a result, it was confirmed that the yield strength of a high-manganese steel laser welding part was 97.5% of that of a base metal, and its tensile strength was 93.5% of that of a base metal.

Design and Property Analysis of the Metal Mesh Reinforced LVL

2010 ◽  
Vol 113-116 ◽  
pp. 2145-2149
Author(s):  
Ying Cheng Hu ◽  
Jin Li ◽  
Fang Chao Cheng ◽  
Xu Jie Zhang
Keyword(s):  
Mechanical Properties ◽  
Modulus Of Elasticity ◽  
Modulus Of Rupture ◽  
Bending Test ◽  
Metal Mesh ◽  
Fast Growing ◽  
Laminated Veneer Lumber ◽  
Property Analysis ◽  
Wood Grain

This study mainly analyzed the factors that affected the mechanical properties of laminated veneer lumber（LVL）. To increase the mechanical properties, metal mesh was inserted into LVL that made of fast-growing timber. Effects of different factors were evaluated on the mechanical properties of LVL, several enhancement modes of metal mesh were designed to reinforce the LVL. Then, the mechanical properties (modulus of rupture and modulus of elasticity) of the LVL specimens were measured by static bending test. The results of different enhancement modes were analyzed and compared to investigate the effects of different factors. The position of metal mesh and the mesh number of metal mesh make significant effects on the MOE; the type of metal mesh and the angle of metal mesh-wood grain do not have any obvious effects on the MOE. The type of metal mesh and the position of metal mesh make significant effects on the MOR; the mesh number of metal mesh and the angle of metal mesh-wood grain do not have any obvious effects on the MOR.

Evaluating the Strength of the Friction Stir Welded Joints at Various Rotational Speeds

2013 ◽  
Vol 446-447 ◽  
pp. 312-315
Author(s):  
Ramaraju Ramgopal Varma ◽  
Abdullah Bin Ibrahim ◽  
B. Ravinder Reddy
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Friction Stir Welding ◽  
Yield Strength ◽  
Welded Joints ◽  
Rotational Speed ◽  
Testing Machine ◽  
Friction Stir ◽  
Universal Testing ◽  
Welding Technique

The present research paper aims in evaluating the strength of the welded AA6351 alloy plates of 6 mm thick by using friction stir welding technique at different rotational speeds The applied welding technique is capable of achieving the mechanical properties of the alloy close to that of the original alloy. In the present investigation, the speeds of the spindle were varied from 1100 rpm to 1500 rpm with a constant transverse speed of 20 mm/min. The tensile strength of the joints is determined by an universal testing machine. The results from the present investigation show that the values of the yield strength were very much closer to the values of the AA6351Alloy prior to welding. It has been found from the experiments that the strength of the joints increases with the increase in the rotational speed; however, the same is decreasing after achieving certain speed.

Structural, Physical and Mechanical Properties of Mg-Al Alloys Processed under CO2 Atmosphere

2012 ◽  
Vol 545 ◽  
pp. 247-250 ◽  
Author(s):  
Subramanian Jayalakshmi ◽  
Khoo Chee Guan ◽  
Kuma Joshua ◽  
Manoj Gupta
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Yield Strength ◽  
Magnesium Alloys ◽  
Physical And Mechanical Properties ◽  
Melting Process ◽  
Al Alloys ◽  
Compressive Yield Strength ◽  
Protective Atmospheres

Magnesium alloys are the lightest structural materials known that are increasingly replacing steel and aluminium. However, due to its flammable nature, protective atmospheres are employed during Mg-alloy production. In this novel work, Mg-Al alloys with ~3 and ~5 wt.% Al were processed in CO2atmosphere, so as to utilize the CO2during the melting process. The cast Mg-Al alloys were extruded and studied for their structural, physical and mechanical properties. Results showed improvements in mechanical properties such as hardness, tensile strength and compressive yield strength. The improvement in properties was attributed to thein situformation of Al4C3arising due to molten metal-carbon interaction. It is noteworthy that the incorporation of CO2during processing did not adversely affect the mechanical properties of the alloys. Further, the process is eco-friendly as it not only utilized CO2, but also eliminates use of harmful cover gases.

scholarly journals Effect of the Degree of Conversion on Mechanical Properties and Monomer Elution from Self-, Dual- and Light-Cured Core Composites

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5642
Author(s):  
Branislava Petronijevic Sarcev ◽  
Sebastian Balos ◽  
Dubravka Markovic ◽  
Ivan Sarcev ◽  
Marija Vukcevic ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Vickers Hardness ◽  
Modulus Of Elasticity ◽  
Testing Machine ◽  
Degree Of Conversion ◽  
Clinical Use ◽  
Universal Testing ◽  
Post Test ◽  
One Way Anova

The objective of this work was to measure and correlate the degree of conversion (DC), mechanical properties and monomer elution from self-, dual- and light-cured core composites. Five samples of each of the following materials were prepared for each test: Clearfil (Core, Photo Core, Automix), Bisco (Core-Flo, Light-Core and Bis-Core). DC was determined using FTIR, compressive and flexural strength and modulus of elasticity using a universal testing machine and microhardness using Vickers hardness. Elution was measured using HPLC. One-way ANOVA with Tukey’s post-test and Pearson’s correlation were used to statistically analyze the data. DC of Clearfil-Dual (70.1%) and Clerafil-Photo (66.8%) were higher than Clearfil-Self (55.4%) and all Bisco materials (51.4–55.3%). Flexural strength of Clearfilwas higher than that of Bisco composites. The Microhardness of Clearfil-Dual (119.8VHN) and Clearfil-Photo (118.0VHN) were higher compared to other materials. The greatest elution was detected from self-cured materials. DC positively correlated to microhardness and compressive/flexural strength and negatively to BisGMA elution. Clearfil-Photo and Automix showed higher conversion, lower monomer elution and, generally, better mechanical properties. Self-cured composites should not be recommended for routine clinical use as their performance was inferior to dual- and light-cured composites. Microhardness may be used as an indicator of elution.

scholarly journals Influence of Concentrations of Methacrylate and Acrylate Monomers on the Properties of Fiber Reinforced Polymethyl Methacrylate Denture Base Materials

2018 ◽  
Vol 26 (2) ◽  
pp. 329-350 ◽  
Author(s):  
Faik Tugut ◽  
Mehmet Turgut ◽  
Dursun Saraydin
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Testing Machine ◽  
Weight Ratio ◽  
Acrylic Resin ◽  
Bending Test ◽  
Control Group ◽  
Test Machine ◽  
Fiber Reinforced ◽  
Significant Difference

Abstract The study aimed to evaluate the effects of adding different concentrations of 2 hydroxyethyl methacrylate (HEMA), 2-hydroxyethyl acrylate (HEA), ethyl methacrylate (EA) and isobutyl methacrylate (IBMA) monomers on the structural, thermal and mechanical properties of a fiber reinforced heat-polymerized acrylic resin. For each test, 126 acrylic resin specimens were fabricated and divided into 6 groups with 7 specimens each. One group was the control group, the other one is a fiber reinforced group and others were the test groups, which were formed according to the different concentrations of monomers. 6 mm length, and the weight ratio of 3% short glass fibers are added to acrylic powder polymerized by heating. The 2%, 5%, 10%, at 20 % ratios of different comonomers added to a monomer of MMA are composed of copolymer structures. Flexural strength was assessed with a three-point bending test using a universal testing machine. Impact strength testing was conducted using an impact test machine by the Charpy method. The analysis of the connection between acrylic resin and fiber by SEM and structural changes in the acrylic resin was investigated by FTIR spectroscopy. Data analyses using analysis of Kruskal-Wallis and Mann-Whitney U tests (α=0.05) significant difference tests showed that adding 2%, 5% HEMA and IBMA monomers significantly increased the flexural and impact strength compared to the control, only fiber and others group (P< 0.05). It is observed that the process of adding low concentration of HEMA and IBMA monomers improved certain mechanical properties of fiber reinforced with polymethylmethacrylate.

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