scholarly journals Impact and Flexural Strength, and Fracture Morphology of Acrylic Resins With Impact Modifiers

2009 ◽  
Vol 3 (1) ◽  
pp. 137-143 ◽  
Author(s):  
Fernanda Faot ◽  
Leonardo H V Panza ◽  
Renata C M Rodrigues Garcia ◽  
Altair Antoninha Del Bel Cury
Keyword(s):  
Impact Strength ◽  
Flexural Strength ◽  
High Capacity ◽  
Young Modulus ◽  
Fracture Morphology ◽  
Mechanical Tests ◽  
Bending Test ◽  
Mean Values ◽  
Acrylic Resins ◽  
The Impact

Objectives:This study evaluated the impact and flexural strength and analyzed the fracture behavior of acrylic resins.Methods:Eighteen rectangular specimens were fabricated of Lucitone 550, QC 20 (both unreinforced acrylic resins), Impact 1500 (extra strength impact), Impact 2000 (high impact) according to the manufacturers’ instructions. The impact strength was evaluated in notched specimens (50x6x4mm) and flexural strength in unotched (64x10x3.3mm), using three-point bending test, as well as, stress at yield, Young modulus and displacement at yield. Fragments from mechanical tests were observed by SEM. Data from impact strength, stress at yield and displacement at yield were analyzed by 1-way ANOVA and Tukey test (α=0.05). Young modulus values were analyzed by One-way ANOVA and Dunnett T3 multiple comparisons test (α=0.05).Results:Mean values of impact strength and stress at yield values were higher (P<.005) for Impact 2000 while Young modulus was higher (P<.05) for Lucitone 550; Impact 1500 and Impact 2000 showed significant values (P<.05) in the displacement at yield. Impact fractures of the all acrylic resins were brittle. Bending fractures of Lucitone 550 and Impact 2000 were brittle, QC 20 fractures were ductile and Impact 1500 showed brittle (75%) and ductile (25%) fractures.Conclusion:Within the limitations of this study, the Impact 2000 showed improved mechanical properties with high capacity of stress absorption and energy dissipation before the fracture.

scholarly journals Effect of repeated disinfections by microwave energy on the physical and mechanical properties of denture base acrylic resins

2009 ◽  
Vol 20 (2) ◽  
pp. 132-137 ◽  
Author(s):  
Rafael Leonardo Xediek Consani ◽  
Douglas Duenhas de Azevedo ◽  
Marcelo Ferraz Mesquita ◽  
Wilson Batista Mendes ◽  
Paulo César Saquy
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Flexural Strength ◽  
Physical And Mechanical Properties ◽  
Knoop Hardness ◽  
Microwave Energy ◽  
Bending Test ◽  
Denture Base ◽  
Acrylic Resins ◽  
The Impact

The present study evaluated the effect of repeated simulated microwave disinfection on physical and mechanical properties of Clássico, Onda-Cryl and QC-20 denture base acrylic resins. Aluminum patterns were included in metallic or plastic flasks with dental stone following the traditional packing method. The powder/liquid mixing ratio was established according to the manufacturer's instructions. After water-bath polymerization at 74ºC for 9 h, boiling water for 20 min or microwave energy at 900 W for 10 min, the specimens were deflasked after flask cooling and finished. Each specimen was immersed in 150 mL of distilled water and underwent 5 disinfection cycles in a microwave oven set at 650 W for 3 min. Non-disinfected and disinfected specimens were subjected to the following tets: Knoop hardness test was performed with 25 g load for 10 s, impact strength test was done using the Charpy system with 40 kpcm, and 3-point bending test (flexural strength) was performed at a crosshead speed of 0.5 mm/min until fracture. Data were analyzed statistically by ANOVA and Tukey's test (α= 0.05%). Repeated simulated microwave disinfections decreased the Knoop hardness of Clássico and Onda-Cryl resins and had no effect on the impact strength of QC-20. The flexural strength was similar for all tested resins.

scholarly journals Effect of microwave disinfection on physical and mechanical properties of acrylic resins

2008 ◽  
Vol 19 (4) ◽  
pp. 348-353 ◽  
Author(s):  
Rafael Leonardo Xediek Consant ◽  
Erica Brenoe Vieira ◽  
Marcelo Ferraz Mesquita ◽  
Wilson Batista Mendes ◽  
João Neudenir Arioli-Filho
Keyword(s):  
Flexural Strength ◽  
Room Temperature ◽  
Physical And Mechanical Properties ◽  
Hardness Test ◽  
Knoop Hardness ◽  
Microwave Energy ◽  
Bending Test ◽  
Acrylic Resins ◽  
Strength Tests ◽  
The Impact

This study evaluated the effect of microwave energy on the hardness, impact strength and flexural strength of the Clássico, Onda-Cryl and QC-20 acrylic resins. Aluminum die were embedded in metallic or plastic flasks with type III dental stone, in accordance with the traditional packing technique. A mixing powder/liquid ratio was used according to the manufacturer's instructions. After polymerization in water batch at 74ºC for 9 h, boiling water for 20 min or microwave energy at 900 W for 10 min, the specimens were deflasked after flask cooling at room temperature, and submitted to finishing. Specimens non-disinfected and disinfected by microwave irradiation were submitted to hardness, impact and flexural strength tests. Each specimen was immersed in distilled water and disinfected in a microwave oven calibrated to 650 W for 3 min. Knoop hardness test was performed with 25 g load for 10 s, impact test was carried out using the Charpy system with 40 kpcm, and 3-point bending test with a crosshead speed of 0.5 mm/min until fracture. Data were submitted to statistical analysis by ANOVA and Tukey's test (?=0.05). Disinfection by microwave energy decreased the hardness of Clássico and Onda-Cryl acrylic resins, but no effect was observed on the impact and flexural strength of all tested resins.

scholarly journals Reinforcement of PMMA Denture Base Material with a Mixture of ZrO2Nanoparticles and Glass Fibers

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Mohammed M. Gad ◽  
Ahmad M. Al-Thobity ◽  
Ahmed Rahoma ◽  
Reem Abualsaud ◽  
Fahad A. Al-Harbi ◽  
...  
Keyword(s):  
Impact Strength ◽  
Flexural Strength ◽  
Glass Fibers ◽  
Base Material ◽  
Test Group ◽  
Charpy Impact ◽  
Bending Test ◽  
Control Group ◽  
Denture Base ◽  
The Impact

This study is aimed at evaluating the hybrid reinforcement effects of zirconium oxide nanoparticles (nano-ZrO2) and glass fibers (GFs) at different ratios on the flexural and impact strengths of a polymethylmethacrylate (PMMA) denture base. A total of 160 specimens were fabricated from heat-polymerized acrylic resins using the water bath technique. For the control group, the specimens did not receive any additions; for the test group, different concentrations of nano-ZrO2/GFs at 5% of the PMMA polymer were added. The concentrations of nano-ZrO2/GFs were as follows: 5%–0%, 4%–1%, 3%–2%, 2.5%–2.5%, 2%–3%, 1%–4%, and 0%–5%. The flexural strength was measured using the three-point bending test. The impact strength was measured using the Charpy impact test. Results were tabulated and analyzed using one-way analysis of variance (ANOVA) and the Tukey–Kramer multiple comparison test (p≤0.05). The flexural and impact strengths of PMMA-nano-ZrO2 + GF composites were significantly improved when compared with those of pure PMMA (p<0.05). The maximum flexural strength (94.05 ± 6.95 MPa) and impact strength (3.89 ± 0.46 kJ/m2) were obtained with PMMA (2.5%)/nano-ZrO2 + 2.5% GF mixtures and could be used for removable prosthesis fabrication.

scholarly journals Effect of Incorporation of Different Concentrations of Silver Nanoparticles as an Antimicrobial Agent on the Flexural and Impact Strength of Heat-Cured Denture Base Resin

2021 ◽  
Author(s):  
Piyali Sarkar ◽  
Sandeep Garg ◽  
Nidhi Mangtani Kalra
Keyword(s):  
Silver Nanoparticles ◽  
Impact Strength ◽  
Flexural Strength ◽  
Antimicrobial Agent ◽  
Bending Test ◽  
Denture Base ◽  
Significant Difference ◽  
Base Resin ◽  
The Impact ◽  
Denture Base Resin

Abstract Aim This article evaluates the effect of incorporating different concentrations of silver nanoparticles as an antimicrobial agent on the flexural and impact strength of heat-cured denture base resin. Material and Methods A total of 80 specimens of polymethyl methacrylate resin were fabricated (40 for flexural strength and 40 for impact strength). Specimens were fabricated using stainless steel die of dimension 65 mm × 10 mm × 2.5 mm as per the American Dental Association specification no. 12, and 50 mm × 6 mm × 4 mm as per ISO 1567:1999 for flexural strength and impact strength, respectively, and were divided into four groups (A, B, C, and D) based on the concentrations of silver nanoparticles (0%, 2.5%, 5%, and 10%). The specimens were subjected to three-point bending test and Izod impact tester for testing flexural and impact strength, respectively. Data obtained was compiled and analyzed using one-way analysis of variance and post hoc tests. Results Results showed that for both the properties, maximum strength was observed in group A (control) followed by groups B and C, and minimum was observed in group D. A statistically significant difference in flexural strength was found among all the groups, whereas no statistically significant difference in impact strength was found among any of the groups. Conclusion Within the limitations of this in vitro study, it was concluded that though incorporation of silver nanoparticles exhibited no effect on the impact strength of heat cure denture base resin, it decreased the flexural strength, so it should be used cautiously.

scholarly journals Mechanical Properties of Heat Cured Acrylic Resin Reinforced with Natural Sisal Fibers Powder

2021 ◽  
Vol 2114 (1) ◽  
pp. 012023
Author(s):  
Teba M. Hameed ◽  
Balqees M. Al-Dabbagh ◽  
Ragdaa K. Jasim
Keyword(s):  
Tensile Strength ◽  
Impact Strength ◽  
Flexural Strength ◽  
Acrylic Resin ◽  
Impact Testing ◽  
Bending Test ◽  
Heat Cure ◽  
Significant Difference ◽  
Sisal Fibers ◽  
The Impact

Abstract Materials and Methods: In total, 90 specimens were prepared to be used in the study. The specimens were divided into (3) main groups depended on the presence of sisal fibers powder, first group (30) specimens of heat cure PMMA without additives (control), second and third experimental groups of 60 specimens of heat cure PMMA with salinized sisal fibers powder with two different weight percentages (1 and 3%) wt. Three point bending test was used to measure the flexural strength of the specimens, while the impact strength was done by impact testing Charpy’s machine and tensile test was performed according to ASTM (D-638). Data analysis was performed using (ANOVA) test. The results of this study refer to a highly significant in the flexural strength and tensile strength of specimens reinforced with sisal fibers powder compared with control specimens. Non-significant difference was detected in impact strength among the reinforced groups and control gro. Reinforcement of acrylic resin with natural sisal fibers powder affects its flexural strength and tensile strength with non-significant in impact strength.

scholarly journals Polymethylmethacrylate Incorporating Nanodiamonds for Denture Repair: In Vitro Study on the Mechanical Properties

2021 ◽  
Author(s):  
Mohammed Moustafa Ahmed Gad ◽  
Mohamed Saber Ali ◽  
Ahmad M. Al-Thobity ◽  
Yousif A. Al-Dulaijan ◽  
Mai El Zayat ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Impact Strength ◽  
Flexural Strength ◽  
In Vitro Study ◽  
Acrylic Resin ◽  
Bending Test ◽  
Control Group ◽  
Nd Addition ◽  
The Impact

Abstract Objective This study aimed to evaluate the effect of nanodiamond (ND) addition to repair resin with repair gap modifications on the flexural and impact strength of repaired polymethylmethacrylate denture base. Materials and Methods Heat-polymerized acrylic resin specimens (N = 100/test) were prepared and sectioned to half creating two repair gaps: 2.5- and 0 mm with 45 degrees beveling. They were further divided into subgroups (n = 20) according to ND concentration (control, 0.25%ND, and 0.50%ND), thermocycling (500 cycles) was done to half the specimens in each subgroup. Flexural strength was tested using 3-point bending test and impact strength was tested by Charpy's impact test. Analysis of variance and post-hoc Tukey's tests were performed for data analysis (α = 0.05). Scanning electron microscope was employed for fracture surface analysis and ND distribution. Results Before and after thermocycling, the addition of ND significantly increased the flexural strength and elastic modulus in comparison to control group (p ˂ 0.001), while 0 mm repair gap showed insignificant difference between ND-reinforced groups (p ˃ 0.05). Regarding impact strength, ND addition increased the impact strength with 0 mm gap in comparison to control and 2.5 mm with ND (p˂0.001), while later groups showed no significant in between (p ˃ 0.05). Comparing thermocycling effect per respective concentration and repair gap, thermocycling adversely affected all tested properties except elastic modulus with 0 mm–0.25 and 0 mm–0.5% and impact strength with 2.5 mm, 2.5 mm–0.25%, 2.5 mm– 0.5% (p ˃ 0.05). Conclusion ND addition combined with decreased repair gap improved the flexural strength, elastic modulus, and impact strength of repaired denture resin, while thermocycling has a negative effect on denture repair strength.

A novel recycled polyethylene terephthalate/polyamide 11 (rPET/PA11) thermoplastic blend

2021 ◽  
pp. 147776062110010
Author(s):  
Zahid Iqbal Khan ◽  
Zurina Binti Mohamad ◽  
Abdul Razak Bin Rahmat ◽  
Unsia Habib ◽  
Nur Amira Sahirah Binti Abdullah
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Flexural Strength ◽  
Polyethylene Terephthalate ◽  
Practical Implication ◽  
Polyamide 11 ◽  
Recycled Polyethylene ◽  
Twin Screw ◽  
Electron Microscopy Analysis ◽  
The Impact

This work explores a novel blend of recycled polyethylene terephthalate/polyamide 11 (rPET/PA11). The blend of rPET/PA11 was introduced to enhance the mechanical properties of rPET at various ratios. The work’s main advantage was to utilize rPET in thermoplastic form for various applications. Three different ratios, i.e. 10, 20 and 30 wt.% of PA11 blend samples, were prepared using a twin-screw extruder and injection moulding machine. The mechanical properties were examined in terms of tensile, flexural and impact strength. The tensile strength of rPET was improved more than 50%, while the increase in tensile strain was observed 42.5% with the addition of 20 wt.% of PA11. The improved properties of the blend were also confirmed by the flexural strength of the blends. The flexural strength was increased from 27.9 MPa to 48 MPa with the addition of 30 wt.% PA11. The flexural strain of rPET was found to be 1.1%. However, with the addition of 10, 20 and 30 wt.% of PA11, the flexural strain was noticed as 1.7, 2.1, and 3.9% respectively. The impact strength of rPET/PA11 at 20 wt.% PA11 was upsurged from 110.53 to 147.12 J/m. Scanning electron microscopy analysis revealed a dispersed PA11 domain in a continuous rPET matrix morphology of the blends. This work practical implication would lead to utilization of rPET in automobile, packaging, and various industries.

scholarly journals The Spread of Corrosion in Cast Iron and its Effect on the Life Cycle of Transportation Vehicles

2017 ◽  
Vol 65 (2) ◽  
pp. 383-389 ◽  
Author(s):  
Tomáš Binar ◽  
Jiří Švarc ◽  
Petr Dostál ◽  
Michal Šustr ◽  
Jan Tippner
Keyword(s):  
Impact Strength ◽  
Fractographic Analysis ◽  
Bending Test ◽  
Material Surface ◽  
Bending Tests ◽  
Corrosion Tests ◽  
Fracture Surfaces ◽  
Impact Bending ◽  
Notch Impact Strength ◽  
The Impact

This article deals with the spread of corrosion in material at different exposure times, and its effect on the measured brittle fracture and notch impact strength under different temperature conditions. To assess the degradational effect of corrosion on the material characteristics represented by the measured impact strength, we conducted a fractographic analysis of fracture surfaces, the aim of which was to evaluate the spread of corrosion in the material. In the first part of the experiment, two corrosion tests are simulated with a duration time of 432 and 648 hours, to compare the degradation effect of corrosion on the notch impact strength, depending on the duration of the corrosion tests. The following part shows the results of the impact bending test, where the experiment was conducted in an area of reduced and increased temperatures. The final part summarizes the results of the fractographic analysis of sample fracture surfaces from the impact bending tests. Based on the measured the length of the corrosion cracks, we analyzed the sample at the notch and from the material surface after the impact bending test.

scholarly journals Effect of adding TiO2 nanoparticles on the SEM morphology and mechanical properties of conventional heat-cured acrylic resin

2019 ◽  
Vol 13 (3) ◽  
pp. 234-240
Author(s):  
Elnaz Moslehifard ◽  
Mahmood Robati Anaraki ◽  
Saeed Shirkavand
Keyword(s):  
Impact Strength ◽  
Tio2 Nanoparticles ◽  
Cross Sections ◽  
Average Particle Size ◽  
Acrylic Resin ◽  
Mechanical Tests ◽  
Average Particle ◽  
Sem Images ◽  
Tio2 Nps ◽  
The Impact

Background. The current study evaluated the compressive, flexural and impact strengths of heat-cured acrylic resins reinforced by TiO2 nanoparticles (NPs). Methods. TiO2 NPs were provided and characterized using scanning electron microscopy (SEM) to determine their morphology and crystalline structure. For three mechanical tests, 12 acrylic resin groups (n=9), totaling 108 specimens, were prepared using a special mold for each test, with TiO2 nanoparticle contents of 0, 0.5, 1 or 2 wt% in different groups. After curing, the compressive, flexural and impact strengths of the specimens were examined according to ISO 1567. Results. In the SEM and XRD study of TiO2 NPs, anatase was identified as the major crystalline phase followed by rutile (average particle size: 20.4 nm). SEM images showed that the nanocomposite with 1 wt% NPs had a more homogenized blend. 1 wt% TiO2 nanocomposite exhibited a higher, but non-significant, impact strength compared to the controls. ANOVA showed significant differences in the impact and flexural strengths between nanocomposites with various contents of TiO2 NPs. Conclusion. The nanocomposite with 1 wt% TiO2 NPs exhibited fewer micro-pores and micro-cracks in the SEM cross-sections. A non-significant increase was also observed in the impact strength with TiO2 NPs at 1 wt%. Further increase in TiO2 NPs decreased both the impact and flexural strengths. The compressive strength of the heat-cured acrylic resin was not affected by the incorporation of NPs.

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