scholarly journals EFFECT OF SILVER NANOPARTICLES FILLERS ADDITION ON FLEXURAL STRENGTH, FRACTURE TOUGHNESS, IMPACT STRENGTH, COMPRESSIVE STRENGTH AND HARDNESS OF HEAT-POLYMERIZED ACRYLIC RESIN.

2019 ◽  
Vol 7 (9) ◽  
pp. 1419-1422
Author(s):  
Anas AAlsukhayri ◽  
◽  
Abdulrahman AAlwagdani ◽  
Mohamed IIbrahim ◽  
Mohamed KFahmi. ◽  
...  
Biomimetics ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 7
Author(s):  
Mostafa Shahabi ◽  
Sorour Movahedi Fazel ◽  
Abdolrasoul Rangrazi

Improvement of the antibacterial properties of acrylic resins, used in the construction of removable orthodontic appliances, is an important strategy to reduce the incidence of caries and oral diseases in orthodontic treatments. The addition of antimicrobial agents to acrylic resins is one of the effective methods to enhance the antimicrobial properties of these materials. However, one main concern is that modification of acrylic resin has negative effects on its mechanical properties. Recently, chitosan nanoparticles (NPs), as biocompatible and biodegradable polysaccharides with remarkable antimicrobial properties, have been used in different areas of dentistry and medicine. This study aimed to investigate the effects of adding chitosan NPs on the mechanical properties of a cold-cure orthodontic acrylic resin. The chitosan NPs were added to the acrylic resin in various weight percentages: 0% (control), 0.5%, 1%, 2%, and 4%. The flexural strength, compressive strength, Vickers microhardness, and impact strength measurements were performed for all five groups. The results showed that adding up to 1% (w/w) chitosan NPs to an acrylic resin had no significant negative effects on its flexural strength and compressive strength, while it decreased these parameters at weight percentages of 2% and 4% (w/w). The results also revealed that modification of acrylic resin with chitosan NPs up to 4% had no significant negative effects on the microhardness and impact strength of acrylic resin. In conclusion, the addition of chitosan NPs up to 1% (w/w) had no significant negative effects on the mechanical properties of cold-cure acrylic resin.


Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3852
Author(s):  
Ahmad Rashedi ◽  
Riadh Marzouki ◽  
Ali Raza ◽  
Nurul Fazita Mohammad Rawi ◽  
J. Naveen

For a sustainable environment, geopolymer (GPO) paste can be used in the construction industry instead of Portland cement. Nowadays, sustainable construction and high-efficacy composites are demanding. Therefore, in the present investigation, the mechanical and microstructural efficacy of carbon-fiber-reinforced fly ash-based GPO with different percentages of nano-sodium dioxide (NS) were studied. The investigated percentages of NS were 0%, 1%, 2%, 3%, and 4%. For all the samples, the carbon fiber content was kept the same at 0.5% by weight. Different percentages of NS for all five fabricated GPO composite pastes were assessed with scanning electron microscopy (SEM). Various mechanical parameters of GPO—the compressive strength, toughness modulus, hardness, toughness indices, impact strength, fracture toughness, flexural strength, and elastic modulus—were evaluated. The results revealed that the use of 3% NS was the most effective for ameliorating the mechanical, microstructural, and fracture behavior of GPO. The use of 3% NS in carbon-fiber-reinforced GPO paste showed the maximum improvements of 22%, 46%, 30%, 40%, 14%, 38.4%, 50.2%, 31%, and 64% for the compressive strength, flexural strength, elastic modulus, toughness modulus, hardness, compressive stiffness, bending stiffness, fracture toughness, and impact strength, respectively. The SEM study showed that the inclusion of NS improved the microstructure and delivered a denser GPO paste by improving the interfacial zones and quickening the polymerization reaction.


2018 ◽  
Vol 11 (3) ◽  
pp. 1573-1581 ◽  
Author(s):  
Maha M. Turki ◽  
Faiza M. Abdul-Ameer

Scleral acrylic resin is widely used to synthesize ocular prosthesis. However, the properties of this material change over time, thus requiring the prosthesis to be refabricated. Many studies were conducted to improve these properties by reinforcing this material with nanoparticles. This study aims to evaluate the effect of silver nanoparticle powder on the mechanical properties (transverse flexural strength, impact strength, shear bond strength, surface microhardness, and surface roughness) of scleral acrylic resin used for ocular prostheses. Two concentrations were selected from the pilot study and evaluated for their effects on scleral acrylic resin properties. According to the pilot study, 0.01 and 0.02wt% AgNPs powder improved the transverse flexural strength, microhardness, and surface roughness compared with other percentages. The specimens in the main study were divided into (3) main groups, (50) specimens without additives (control group A), (50) experimental specimens (with 0.01wt% AgNPs group B), and (50) experimental specimens (with 0.02 wt% AgNPs group C). Each group was subdivided into (5) equal subgroups depending on the tests used. The data were studied using one way ANOVA and post hoc LSD test. At 0.01 wt% AgNPs addition, the mean values of transverse flexural strength insignificantly increased (p> 0.05), and those of impact strength and shear bond strength significantly increased (p< 0.05) compared with those of the control group. At 0.02 wt% AgNPs addition (group C), the mean value of transverse flexural strength significantly increased (p< 0.05), that of impact strength insignificantly increased (p> 0.05), and that of shear bond strength increased with high significance (p< 0.01) compared with those of the control group. Group C showed insignificant increase in the mean values of transverse flexural strength, impact strength, and shear bond strength (p. 0.05) compared with group B. The scleral acrylic resin added with 0.01 and 0.02 wt% AgNPs showed insignificant increase in microhardness and insignificant decrease in surface roughness. The addition of AgNPs powder in both concentrations improved the mechanical properties of scleral acrylic resin used for ocular prostheses.


2020 ◽  
Vol 38 (8A) ◽  
pp. 1117-1125
Author(s):  
Teeb A. Mohameed ◽  
Sihama I. Salih ◽  
Wafaa M. Salih

 Many of the polymeric materials used for structural purposes have weak mechanical properties, these characteristics can therefore be improved by preparing a hybrid laminar composite. In this work use melting mixing method using screw extruder to prepare sheets of polymer blends and nanocomposites based on polymer blends, and using a hot hydraulic press machine to prepared hybrid laminates composites. Two groups of hybrid laminar composites were prepared, the first group is consist of [((94%PP: 5%PMMA: 1 %( PP-g-MA)): 0.3% ZrO2): 6%KF and 8%KF] and the second group is [((94%PP: 5%UHMWPE: 1 %( PP-g-MA)): 0.3% ZrO2): 6%KF and 8%KF]. The results illustrated the impact strength and fracture toughness are increase with increased weight percentage of Kevlar fiber in for both groups of laminar composites and the highest values for two groups are (58.1, 54.95 KJ/M2) and (8.4, 9.16 MPa√m) respectively, any that, at the rate of increment reached to (120.4%, 107%) and (52.7%, 66.5%) respectively, compared with the neat PP. Moreover, the flexural strength values of the first group samples of hybrid laminar composite remained constant, when added kevlar fiber to nanocomposite. While, the flexural strength values of the second group samples of hybrid laminar composite increase with increase the ratio of kevlar fiber in composite to reach the maximum values (92 MPa) at 8% wt. of kevlar fiber, any, at the rate of increment reached to 39.4% compared with the neat PP. As well as, the results shown that the flexural properties and fracture toughness of the second group samples higher than they are for the first group samples.


Alloy Digest ◽  
1975 ◽  
Vol 24 (6) ◽  

Abstract COLMONOY NO. 52SA comprises a nickel-base alloy recommended for hard surfacing parts to resist wear, corrosion, heat and galling. Deposits, which have only moderate hardness (Rockwell C 45-50), may be machined with carbide tooling. Also, deposits have fairly good ductility and impact strength. Colmonoy No. 52SA is supplied as an atomized powder for application with Wall Colmonoy's SPRAYWELD Process. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, machining, joining, and powder metal forms. Filing Code: Ni-218. Producer or source: Wall Colmonoy Corporation.


Author(s):  
Mostafa Hassani Niaki ◽  
Morteza Ghorbanzadeh Ahangari ◽  
Abdolhossein Fereidoon

This paper studies the mechanical properties of polymer concrete (PC) with three types of resin systems. First, the effect of 0.5 wt% up to 3 wt% basalt fiber on the mechanical properties of a quaternary epoxy-based PC is investigated experimentally, and the best weight percentage of basalt fiber is obtained. The results show that adding basalt fiber to PC caused the greatest enhancement within 10% in compressive strength, 10% in flexural strength, 35% in the splitting tensile strength, and 315% in impact strength. In the next step, the effect of nanoclay particles on the mechanical properties of basalt fiber-reinforced PC (BFRPC) is analyzed experimentally. Nanoclays increase the compressive strength up to 7%, flexural strength up to 27%, and impact strength up to 260% but decrease the tensile strength of the PC. Field-emission scanning electron microscopy (FESEM) analysis is performed to study the fracture surface and morphology of various concrete specimens. In the last step, we consider the effect of two other different resin systems, rigid polyurethane and rigid polyurethane foam on the mechanical properties of reinforced polymer concrete. A comparison study presents that the epoxy PC has a higher specific strength than the polyurethane and ultra-lightweight polyurethane foam PC.


2011 ◽  
Vol 374-377 ◽  
pp. 1499-1506
Author(s):  
Rong Hui Zhang ◽  
Jian Li

In this study, the effect of micro-expansion high strength grouting material (EGM) and Modified polypropylene coarse fiber (M-PP fiber) on the mechanical properties of lightweight concrete are investigated. The influence of EGM and M-PP fiber on compressive strength , flexural strength and drying shrinkage of concrete are researched, and flexural fracture toughness are calculated. Test results show that the effect of EGM and M-PP fiber volume fraction (Vf) on flexural strength and fracture toughness is extremely prominent, compressive strength is only slightly enhanced, and the rate of shrinkage is obviously decreased. It is observed that the shape of the descending branch of load-deflection and the ascending branch of shrinkage-age tends towards gently with the increase of Vf. And M-PP fiber reinforced lightweight aggregate concrete is more economical.


2010 ◽  
Vol 21 (1) ◽  
pp. 55-59 ◽  
Author(s):  
Fabiana Gouveia Straioto ◽  
Antonio Pedro Ricomini Filho ◽  
Alfredo Júlio Fernandes Neto ◽  
Altair Antoninha Del Bel Cury

The addition of different polymers, such as polytetrafluorethylene (PTFE), to denture base resins could be an option to modify acrylic resin mechanical properties. This study evaluated the surface hardness, impact and flexural strength, flexural modulus and peak load of 2 acrylic resins, one subjected to a long and another subjected to a short polymerization cycle, which were prepared with or without the addition of 2% PTFE. Four groups were formed according to the polymerization cycle and addition or not of PTFE. Forty specimens were prepared for each test (10 per group) with the following dimensions: hardness (30 mm diameter x 5 mm thick), impact strength (50 x 6 x 4 mm) and flexural strength (64 x 10 x 3.3 mm) test. The results of the flexural strength test allowed calculating flexural modulus and peak of load values. All tests were performed in accordance with the ISO 1567:1999 standard. Data were analyzed statistically by ANOVA and Tukey's test with the level of significance set at 5%. No statistically significant differences (p>0.05) were found for surface hardness. Flexural strength, impact strength and peak load were significantly higher (p<0.05) for resins without added PTFE. The flexural modulus of the acrylic resin with incorporated 2% PTFE polymerized by long cycle was significantly higher (p<0.05) than that of the other resins. Within the limits of this study, it may be concluded that the addition of PTFE did not improve the mechanical properties of the evaluated acrylic resins.


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