scholarly journals The effect of the accelerated aging on the mechanical properties of the PMMA denture base materials modified with itaconates

2011 ◽  
Vol 65 (6) ◽  
pp. 707-715 ◽  
Author(s):  
Pavle Spasojevic ◽  
Milorad Zrilic ◽  
Dragoslav Stamenkovic ◽  
Sava Velickovic
Keyword(s):  
Tensile Strength ◽  
Impact Strength ◽  
Testing Machine ◽  
Base Material ◽  
Accelerated Aging ◽  
Charpy Impact ◽  
Accelerated Ageing ◽  
Denture Base ◽  
Elongation At Break ◽  
Charpy Impact Strength

This study evaluated the effect of accelerated ageing on the tensile strength, elongation at break, hardness and Charpy impact strength in commercial PMMA denture base material modified with di-methyl itaconate (DMI) and di-n-butyl itaconate (DBI). The samples were prepared by modifying commercial formulation by addition of itaconates in the amounts of 2.5, 5, 7.5 and 10% by weight. After polymerization samples were characterized by FT-IR and DSC analysis while residual monomer content was determined by HPLC-UV. Accelerated ageing was performed at 70?C in water for periods of 7, 15 and 30 days. Tensile measurements were performed using Instron testing machine while the hardness of the polymerized samples was measured by Shore D method. The addition of itaconate significantly reduces the residual MMA. Even at the small amounts of added itaconates (2.5%) the residual MMA content was reduced by 50%. The increase of itaconate content in the system leads to the decrease of residual MMA. It has been found that the addition of di-n-alkyl itaconates decreases the tensile strength, hardness and Charpy impact strength and increases elongation at break. Samples modified with DMI had higher values of tensile strength, hardness and Charpy impact strength compared to the ones modified with DBI. This is explained by the fact that DBI has longer side chain compared to DMI. After accelerated ageing during a 30 days period the tensile strength decreased for all the investigated samples. The addition of DMI had no effect on the material ageing and the values for the tensile strength of all of the investigated samples decreased around 20%, while for the samples modified with DBI, the increase of the amount of DBI in the polymerized material leads to the higher decrease of the tensile strength after the complete accelerated ageing period od 30 days, aulthough after the first seven days of the accelerated ageing the values of hardness have increased for all of the investigated samples. Such behavior is explained as the result of the polymer chain relaxation. The values of Charpy impact strength decreased after accelerated ageing. The amount of added DMI have no affect on the decrease of Charpy impact strength after accelerated ageing, the decrease was similar as for pure PMMA. The decrease of Charpy impact strength increased as the amount of added DBI increases.

scholarly journals Improving Mechanical Properties of PLA/Starch Blends Using Masterbatch Containing Vegetable Oil Based Active Ingredients

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2981
Author(s):  
Bianka Nagy ◽  
Norbert Miskolczi ◽  
Zoltán Eller
Keyword(s):  
Impact Strength ◽  
Vegetable Oil ◽  
Rapeseed Oil ◽  
Flexural Modulus ◽  
Charpy Impact ◽  
Sem Images ◽  
Elongation At Break ◽  
Starch Concentration ◽  
Starch Blends ◽  
Charpy Impact Strength

The aim of this research was to increase the compatibility between PLA and starch with vegetable oil-based additives. Based on tensile results, it can be stated, that Charpy impact strength could be improved for 70/30 and 60/40 blends in both unconditioned and conditioned cases, regardless of vegetable oil, while no advantageous change in impact strength was obtained with PLA-g-MA. Considering sample with the highest starch concentration (50%), the flexural modulus was improved by using sunflower oil-based additive, Charpy impact strength and elongation at break was increased using rapeseed oil-based additive in both conditioned and unconditioned cases. SEM images confirmed the improvement of compatibility between components.

scholarly journals The effect of polyamide microparticles addition on some mechanical prop-erties of light-cured acrylic resin

2019 ◽  
Vol 10 (2) ◽  
pp. 1464-1469
Author(s):  
Adnan R. Al Assal ◽  
Abdalbaset A Fatalla ◽  
Mohammed Moudhaffar ◽  
Ghasak H Jani
Keyword(s):  
Tensile Strength ◽  
Impact Strength ◽  
Base Material ◽  
Acrylic Resin ◽  
Strength Test ◽  
Control Group ◽  
Denture Base ◽  
Mean Values ◽  
Transverse Strength ◽  
Transverse Tensile

The general upgrading of polymer denture base material and research continuously looking for ideal restorative dental material with better properties, adequate esthetic properties, less expensive and easier to handle material to develop photo polymerization dental materials. This study was conducted to evaluate the effect of addition polyamide on mechanical microparticle properties light cure denture base material. One hindered sixty specimens from light-cured acrylic resin (Aurora). The divided mainly into four groups according to test used (Transverse strength test, impact strength test, hardness test and tensile strength test) with 40 specimens for each group. The results show an increase in Transverse strength, impact strength, hardness and tensile strength in all experimental group when compared to control group the highest mean values for all tests included in the study appeared in group B 1% polyamide. The addition of polyamide microparticle improves transverse, tensile, impact strength and hardness properties of denture base material.

Effect of inorganic pigments on the properties of coextruded polypropylene-based composites

2016 ◽  
Vol 31 (1) ◽  
pp. 23-33 ◽  
Author(s):  
Svetlana Butylina ◽  
Ossi Martikka ◽  
Timo Kärki
Keyword(s):  
Tensile Strength ◽  
Iron Oxide ◽  
Impact Strength ◽  
Water Immersion ◽  
Tensile Modulus ◽  
Charpy Impact ◽  
Immersion Test ◽  
Accelerated Weathering ◽  
Inorganic Pigments ◽  
Charpy Impact Strength

In this article, the effect of the incorporation of three inorganic pigments on the properties of coextruded polypropylene-based composites was studied. Three different pigments were incorporated in the shell layer of the composites: iron oxide, titanium dioxide (TiO2) and zinc oxide (ZnO). The tensile properties and Charpy impact strength of the composites were tested. A water immersion test was conducted. The morphology of the fractured surfaces of composites was characterised by scanning electron microscopy. The durability of the composites was assessed by testing colour characteristics and tensile strength after 500 hours of accelerated weathering. The results revealed that the TiO2-containing composite had the highest tensile modulus and Charpy impact strength, while the ZnO-containing composite had the lowest tensile strength and Charpy impact strength. Iron oxide was found to have no effect on either the physical or mechanical properties of the composite. The porosity of composites influences their water absorption and thickness swelling. The TiO2-containing composite exhibited better colour stability.

scholarly journals Mechanical Properties of Abaca Fiber Reinforced Urea Formaldehyde Composites

2015 ◽  
Vol 12 (1) ◽  
pp. 54-59 ◽  
Author(s):  
Abhishek Suvarna ◽  
Akash Katagi ◽  
Jackson Pasanna ◽  
Sunil Kumar ◽  
Basavaraju Bennehalli ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Impact Strength ◽  
Flexural Strength ◽  
Urea Formaldehyde ◽  
Charpy Impact ◽  
Fiber Reinforced ◽  
Compression Moulding ◽  
Charpy Impact Strength

The present investigation focuses on the fabrication and mechanical characterization of alkali treated natural abaca fiber reinforced urea formaldehyde composites. The composites were prepared by means of compression moulding, and then the effects of fiber loading on mechanical properties such as tensile strength, flexural strength and impact strength were investigated. The composite with 40 wt% abaca fibers gave excellent tensile strength and flexural strength showing that it has the most superior bonding and adhesion of all the composites. In particular, the highest value, 10.02 kJ/m2 of charpy impact strength is observed in the composite with 50 wt% abaca fiber. This work revealed the potential of using abaca fibers in fiberboard.

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.

Effect of Ethylene Vinyl Axetate (EVA) on the Mechanical Properties of Low-Density Polyethylene/EVA Blends

2019 ◽  
Vol 889 ◽  
pp. 223-230
Author(s):  
Thi Hong Nga Pham ◽  
Thi My Hoa Le ◽  
Xiao Wei Zhang
Keyword(s):  
Tensile Strength ◽  
Impact Strength ◽  
Bending Strength ◽  
Charpy Impact ◽  
Molding Compounds ◽  
Major Significance ◽  
Extensive Range ◽  
Plastic Industry ◽  
The Cost ◽  
Charpy Impact Strength

The extensive range of fillers used nowadays indicated the major significance of filler in the plastic industry. Although their original purpose was to lower the cost of the molding compounds; prime importance is now attached to selective modification of the properties of a specific plastic. In this study, the examples of LDPE/EVA blends, were put into 0, 3, 6, 9, 12 and 15 wt.% of EVA. The tensile strength, bending strength and impact strength of samples were determined according to ASTM D638, ISO 178 and ISO 179. Results showed that when increasing ratio of EVA in LDPE/ EVA blends, tensile strength decreased from 10.9 MPa to 8.6 MPa. Bending strength decreased linearly from 9.63 MPa to 5.46 MPa. Charpy impact strength decreased from 47.5 kJ/m2 to 6.3 kJ/m2. On the contrary, elongation in 100% LDPE is 78.3%; with the appearance of EVA, elongation of the LDPE/ EVA blends increased upto 109.1%. In addition, SEM micrographs indicated that, it was more crystal-clear when the EVA content is less; in the highest EVA content with 15%, it can be seen that the specimen after pressing is slightly opaque and darker than the orthers. From that showed the addition of EVA to the polymer leads the tensile strength, bending strength were not affect much, impact strength decreased but elongation experienced an increase.

scholarly journals Comparison of Properties with Relevance for the Automotive Sector in Mechanically Recycled and Virgin Polypropylene

Recycling ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 76
Author(s):  
Abdelhak Ladhari ◽  
Esra Kucukpinar ◽  
Henning Stoll ◽  
Sven Sängerlaub
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Charpy Impact ◽  
Automotive Sector ◽  
Broad Distribution ◽  
Elongation At Break ◽  
Brittle Behavior ◽  
Recycling Potential ◽  
Using Data ◽  
Charpy Impact Strength

Polypropylene (PP) has a high recycling potential. However, the properties of mechanically recycled PP (R-PP) have not been fully compared to those of virgin PP (V-PP). Therefore, in this study, properties of R-PP and V-PP were compared using data from recyclers, virgin plastic suppliers, and the literature. The properties of recyclates could not be directly correlated either with the properties of the virgin polymers from which the recyclates were made or the recycling parameters. It was found that the MFR of R-PP was higher; MFR R-PP had a median value (m) of 11 g/10 min while MFR V-PP had a median value of 6.3 g/10 min (at 230 °C and with 2.16 kg). In terms of mechanical properties, in many cases R-PP exhibited stiffer and more brittle behavior, with a slightly higher Young’s modulus (ER-PP = 1400 and EV-PP = 1200 MPa), a reduced elongation at break (ɛbR-PP = 4 l.-% and ɛbV-PP = 83 l.-%), and notched charpy impact strength (NCISR-PP = 4.8 and NCISV-PP = 7.5 kJ/m2). However, the values for every property had a broad distribution. In addition to existing information from the literature, our research sheds fresh light on the variation of the characteristics of recycled polypropylenes presently on the market.

scholarly journals Pengaruh penambahan aluminium oksida terhadap kekuatan tarik dan tekan basis gigi tiruan resin akrilik polimerisasi panasThe effect of addition of aluminium oxide on the tensile and compressive strength of a heat-polymerised acrylic resin denture base

2018 ◽  
Vol 30 (3) ◽  
pp. 189
Author(s):  
Actara Rahmadita ◽  
Dwi Tjahyaning Putranti
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Testing Machine ◽  
Base Material ◽  
Aluminium Oxide ◽  
Acrylic Resin ◽  
Strength Test ◽  
Denture Base ◽  
Universal Testing Machine ◽  
Universal Testing

Pendahuluan: Resin akrilik polimerisasi panas (RAPP) merupakan bahan basis gigi tiruan yang paling banyak digunakan, namun memiliki sifat kekuatan tarik dan tekan yang rendah, sehingga diperlukan modifikasi dengan penambahan bahan penguat pada RAPP berupa aluminium oksida (Al2O3) atau alumina. Tujuan penelitian untuk menganalisi pengaruh penambahan aluminium oksida pada bahan basis gigi tiruan RAPP terhadap kekuatan tarik dan tekan. Metode: Jenis penelitian eksperimental laboratoris. Sebanyak 25 sampel berbentuk flat dumbbell shaped berukuran 60x12x3,9 (mm) untuk uji kekuatan tarik dan 25 sampel  berbentuk balok dengan ukuran 10x10x4 (mm) untuk uji kekuatan tekan. Pencampuran bubuk resin-aluminium oksida konsentasi 0,5%, 1,5%, 2,5% dan 3,5% dengan cairan resin dilakukan secara manual. Sampel direndam dalam air dan dimasukkan ke dalam inkubator. Uji dilakukan menggunakan universal testing machine dengan beban 1000N dan kecepatan crosshead 1mm/menit. Data dianalisis dengan uji ANOVA satu arah dan uji LSD. Hasil: Nilai kekuatan tarik kelompok kontrol dan keempat kelompok perlakuan penambahan aluminium oksida 0,5%, 1,5%, 2,5 %, 3,5% berturut turut adalah 50,867 MPa, 47,895 MPa, 45,107 MPa, 42,476 MPa, dan 39,753 MPa; sedangkan nilai kekuatan tekan kelompok kontrol dan keempat kelompok perlakuan penambahan aluminium oksida 0,5%, 1,5%, 2,5%, 3,5% berturut turut adalah 88,267 MPa, 106,085 MPa, 122,283 MPa, 135,367 MPa, dan 156,571 MPa. Penambahan bubuk aluminium oksida pada RAPP dapat menurunkan kekuatan tarik dan meningkatkan kekuatan tekan secara signifikan (p=0,0001 (p<0,05)), seiring dengan meningkatnya jumlah konsentrasi aluminium oksida yang ditambahkan. Simpulan: Penambahan aluminium oksida pada bahan basis gigi tiruan resin akrilik polimerisasi panas berpengaruh terhadap kekuatan tarik dan tekan.Kata kunci: Resin akrilik polimerisasi panas, aluminium oksida, kekuatan tarik, kekuatan tekan. ABSTRACT            Introduction: Heat-polymerised acrylic resin (HPAR) is the most widely used denture base material but has a low tensile and compressive strength thus modification is needed by adding reinforcement in the form of aluminium oxide (Al2O3) or alumina. The research objective was to analyse the effect of adding aluminium oxide on the tensile and compressive strength of HPAR denture base material. Methods: An experimental laboratory research was conducted towards the total of 25 samples in the form of flat dumbbell shape sized 60 x 12 x 3.9 mm for the tensile strength test, and 25 samples in the form of blocks with the size of 10 x 10 x 4 mm for the compressive strength test. The mixture of powdered aluminium oxide resin with the concentrations of 0.5%, 1.5%, 2.5%, and 3.5% with a liquid resin was carried out manually. The sample was then immersed in the water and put in an incubator. The test was performed using a universal testing machine with 1000 N loads and 1 mm/minute crosshead speed. Data obtained were analysed using the one-way ANOVA and LSD test. Result: The tensile strength values of the control group and all four treatment groups added with 0.5%, 1.5%, 2.5%, and 3.5% aluminum oxide were 50.867 MPa, 47.895 MPa, 45.107 MPa, 42.4476 MPa and 39.753 MPa respectively, while the compressive strength values were 88.267 MPa, 106.085, 122.283 MPa, 135.367 MPa, and 156.571 MPa consecutively. Addition of aluminium oxide powder to the HPAR can significantly reduce the tensile and compressive strength (p = 0.0001 (p < 0.05)) along with increasing concentration. Conclusion: Addition of aluminium oxide towards the HPAR denture base affected its tensile and compressive strength.Keywords: Heat-polymerised acrylic resin, aluminium oxide, tensile strength, compressive strength.

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