research centers


Search results: Found 25

Listing 1 - 10 of 25 << page
of 3
>>
Sort by

Article
The effect of addition nano particle ZrO2 on some properties of autoclave processed heat cure acrylic denture base material

Authors: Hussein Karim Hameed حسين كريم حميد --- Hanan Abdul Rahman حنان عبد الرحمن
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2015 Volume: 27 Issue: 1 Pages: 32-39
Publisher: Baghdad University جامعة بغداد

Loading...
Loading...
Abstract

Background: Polymethyl methacrylate (PMMA) is used in denture fabrication and considered as the most reliablematerial for the construction of removable prosthodontic appliances. The material is far from ideal in fulfilling themechanical requirements and the effect of autoclave processing has not been fully determined. The purpose of thisstudy was to evaluate the effect of addition of salinized (ZrO2) Nano fillers in percentages 3%, 5% and 7% by weighton some properties of heat cured acrylic processed the by autoclave and compare it with 0% (control) group .Materials and methods: The silanized(ZrO2) Nano-particles was added to PMMA powder by weight in three differentpercentages 3%, 5% and 7%, mixed by probe ultra-sonication machine.Two hundred specimens were constructedand processed by autoclave and divided into 5 groups according to the test (each group consist of 40 specimens )and each group was subdivided into 4 sub-groups according to the percentage of added (ZrO2) nano-particles(with 10 specimens for each subgroups) . The tests conducted were transverse strength, hardness (shore D), Impactstrength test, surface morphology and apparent porosity. AFM can provide 3D image of the specimen thehomogeneity of nanostructure film, roughness of surface and crystallite size. Scanning electron microscope SEM ofcontrol and salinized Nano ZrO2 reveal the Nano fillers distribution and it is shaped.Results: Highly significant increase in impact strength recorded when acrylic (vertex) mixed with 3%, 5% ZrO2 nanofiller, while a non-significant reduction was observed with 7% ZrO2 addition in comparison to control. Non-significantimprovement in transverse strength when 3% ZrO2 was added, 5% nano addition ZrO2 improved transverse strengthsignificantly while 7% nano addition showed anon significant reduce when these groups compared to the controlgroup .Anon significant reduction in the deformity was seen within 3% nano addition ZrO2 also 5% nano ZrO2 additionreduce the deformity significantly and significant increase was recorded when 7% nano addition ZrO2 was add andwhen these groups are compared to the control group. A significant increase in surface hardness was observed withthe addition of (ZrO2) nano-particles to (PMMA) at the percentage of 3%, highly significant increase at 5% and 7%with addition of modified nano-ZrO2. A non-significant decrease in apparent porosity at 3% and highly significantdecrease in apparent porosity at 5% and 7% with addition of modified nano-ZrO2 were observed. SEM results showeda good distribution of the modified nano-ZrO2 fillers at 3%, 5% and showed aggregation at 7% in the polymer matrix.Conclusion: The addition of modified nano-ZrO2 particles to acrylic resin cured by autoclave improved impact andtransverse strength of denture base nano composite containing 5% of nano-ZrO2. And this strength decreases withfurther increase of nano-ZrO2 filler content. Also addition of modified nano-ZrO2 slightly increaseshardness, thesurfaceroughness and the apparent porosity also decrease by addition of nano ZrO2 percentage increase


Article
Evaluation of Impact and Transverse Strength of Denture Bases Repaired with Nano Reinforced Resin

Loading...
Loading...
Abstract

Background: Failure of resin bases were a major disadvantage recorded in the constructed dentures. Reinforcements of the repair joint with nano fillers represent an attempt to enhance the strength and durability. The purpose of the research was to estimate the influence of nano fillers reinforcement with (ZrO2 and Al2O3) on impact and transverse strength of denture bases repaired with either cold or hot processing acrylic resin.Materials and methods: A hundred and forty (140) samples were processed with hot cured resin and organized in subgroups depending on the repair materials and condition (without repair (control), repair with hot cure, cold cure, hot and cold cure reinforced with either (5% Zr2O or 0.5% Al2O3). The samples in these subgroups were processed depending on the test applied (impact and transverse strength). The samples were immersed in distalled water for about four weeks at 37°C before testing, after that, the samples prepared for each test were subdivided depending on the selected subgroups of the study. Repairing the samples with cold cure resin was done with the aid of Ivomet; after that the samples incubated for 48 hours in 37°C distilled water. Transverse strength test was done by using INSTRON universal testing machine while the impact test was done by using CHARPY impact testing machine.Results: The reinforcement of the repair joint with nano-fillers improves both impact and transverse strengths.Conclusion: Repair strength is directly proportional to the mode of resin processing, reinforcement with nano-fillers improve the strength of the repaired joint significantly


Article
A.C Conductivity and Dielectric Properties of Epoxy - TiO2 Nanocomposites
الخصائص العزلية والتوصيلية المتناوبة لمتراكبات الايبوكسي- TiO2 النانوية

Loading...
Loading...
Abstract

In this paper, A.C conductivity of micro and nano grain size- TiO2 filled epoxy composites is measured. The dielectric material used is epoxy resin, while micro and nano-sized titanium dioxide (TiO2) of grain size (1.5μm, and 50nm) was used as filler at low filler concentrations by weight (3%, and 5%). Additionally the effect of annealing temperature range (293-373)º K and at a frequency range of 102-106 Hz on the A.C conductivity of the various specimens was studied. The result of real permittivity for micro and nanocomposite show that the real permittivity increases with decreasing frequency at range of 102-106Hz. The micron-filled material has a higher real relative permittivity than the nano-filled this is true at all the temperatures measured.The variation of the A.C conductivity with frequency for micro and nanocomposites shows that A.C conductivity for all samples increase with increasing frequency and the temperature dependence on the A.C conductivity increases as the frequency decrease.

في هذا البحث تم قياس التوصيلية المتناوبة لمتراكبات الايبوكسي مع ثاني اوكسيد التيتانيوم ذو الحجم الحبيبي مايكروونانو. المادة العزلية المستخدمة هي راتنج الايبوكسي بينما ثاني اوكسيد التيتانيوم ذو الحجم الحبيبي (1.5μm, and 50nm) تم استخدامه بتراكيز قليلةand 3%) (5% . إضافة لذلك تم دراسة تأثير الحرارة لمدى293-373)º K (ولمدى من الترددات (102-106 Hz ( على التوصيلية المتناوبة لمختلف العينات .تظهرنتائج ثابت العزل الحقيقي للمتراكبات المايكروية ولمتراكبات النانوية الزيادة مع نقصان التردد. كما ان العزلية لمتراكبات الميكرو اعلى مما لمتراكبات النانو وهذا واضح عند كل درجات الحرارة.يوضح تغير التوصيلية المتناوبة مع التردد لمتراكبات الميكروية والنانوية ان التوصيلية المتناوبة تزداد مع زيادة التردد وان التوصيلية المعتمدة على درجات الحرارة تزداد مع نقصان التردد.


Article
Effects of Different Types of Fillers on Dry Wear Characteristics of Carbon-Epoxy Composite
تأثير الحشوات السيراميكية على خواص البلى للمواد المتراكبة للايبوكسي- كاربون

Loading...
Loading...
Abstract

Experimental investigations had been done in this research to demonstrate the effect of carbon fiber and Ceramic fillers contents on the tribological behaviour of (15% volume fraction) carbon-epoxy composite system under varying volume fraction, load, time and sliding distance. The wear resistance were investigated according to ASTM G99-05standard using pin on disc machine to present the composite tribological behaviour. The influence of three ceramic fillers, granite, perlite and calcium carbonate (CaCO3), on the wear of the carbon fabric reinforced epoxy composites under dry sliding conditions has been investigated. The effect of variants in volume fraction, applied load, time and sliding distance on the wear behaviour of polymer composites is studied by measuring the weight changes . In the experiments with wear test pin having flat face in contact with hardening rotating steel disc, sliding speed, time and loads in the range of 200 RPM, 300–900s and 40–60 N respectively was used. It is observed that the wear resistance increase with the increasing of reinforcement material volume fraction while, the wear rate increases with increasing of applied load, time and sliding distance. The results showed that the filler of granite perlite and CaCO3 as filler materials in carbon epoxy composites will increase the wear resistance of the composite greatly than carbon fiber fillers epoxy composite only and granite filled CE Composite exhibited the maximum wear resistance.

في هذا البحث تمت دراسة تأثير الياف الكاربون والحشوات السيراميكية على الخواص الترايبولوجية لراتنجات الايبوكسي المقواة بالياف الكاربون عمليا وعند كسر حجمي 15%. تم دراسة مقاومة البليان وفقا للمواصفةASTM G99-05 باستعمال جهاز المسمار مع القرص الدوار وعند احمال 40–60 N ومسافات انزلاقm 942-1507.2 وازمان مختلفة 300–900s وبعد اجراءالاختبارات لوحظ بان مقاومة البليان تزداد مع زيادة الكسر الحجمي لمواد التدعيم بينما معدل البلى بصورة عامة يزداد بزيادة الحمل المسلط والزمن ومسافة الانزلاق، ويكون معدل البليان للعينات الغير مدعمة اعلى بكثير من العينات المدعمة بالياف الكاربون فقط والعينات المدعمة بنسبة 15% الياف كاربون مع الحشوات السيراميكية المختلفة وان مقاومة البليان للعينات المحتوية على حشوات سيراميكية تكون اعلى من العينات المدعمة بالياف كاربونية فقط وان مقاومة البليان لمجموعة العينات المقواة بالياف كاربون مع كرانيت بلغت اعلى قيمة لها تليها ألعينات المدعمة بالبرلايت ثم عينات كاربونات الكالسيوم. نستنتج من ذالك اضافة الحشوات السيراميكية مع الياف الكاربون يحسن بشكل كبير من مقاومة البليان.


Article
Effects Of Different Types Of Ceramic Fillers On Wear Characteristics Of Glass Fibres-Epoxy Composite
تأثيرات الحشوات السيراميكيه المختلفة على خواص البلى للمواد المتراكبة للايبوكسي- زجاج

Loading...
Loading...
Abstract

Experimental investigations had been done in this research to demonstrate the effect of glass fiber and Ceramic fillers contents on the tribological behaviour of (15% volume fraction) glass-epoxy composite system under varying volume fraction, load, time and sliding distance. The wear resistance were investigated according to ASTM G99-05 (reapproved 2010) standard using pin on disc machine to present the composite tribological behaviour. The influence of three ceramic fillers granite, perlite and calcium carbonate (CaCO3) on the wear of the glass fiber reinforced epoxy composites investigated under dry sliding conditions. The effect of variants in volume fraction, applied load, time and sliding distance on the wear behaviour of polymer composites is studied by applied pin –on-disc method . In the experiments with wear test pin having flat face in contact with hardening rotating steel disc, sliding speed, time and loads in the range of 200 RPM, 300–900s and 40–60 N respectively was used. It is observed that the wear resistance increase with the increasing of reinforcement material volume fraction while, the wear rate increases with increasing of applied load, time and sliding distance. The results showed that the filler of granite, perlite and CaCO3 as filler materials in glass epoxy composites will increase the wear resistance of the composite by 76.15%, 73.8%, 71.8% respectively and greatly than glass fiber fillers epoxy composite only and granite filled GE Composite exhibited the maximum wear resistance.

في هذا البحث تمت دراسة تأثير ألياف الزجاج و الحشوات السيراميكية على الخواص الترايبولوجية لراتنجات الايبوكسي المقواة بألياف الزجاج عمليا وعند كسر حجمي 15 %. تم دراسة مقاومة البليان وفقا للمواصفة ASTM-G99-05 باستعمال جهاز المسمار مع القرص الدوار وعند أحمال40–60 N ومسافات انزلاق 942-1507.2 وازمان مختلفة 300–900s وبعد إجراء الاختبارات لوحظ بان مقاومة البليان تزداد مع زيادة الكسر الحجمي لمواد التدعيم بينما معدل البلى بصورة عامة يزداد بزيادة الحمل المسلط والزمن ومسافة الانزلاق . ويكون معدل البليان للعينات غير المدعمة أعلى بكثير من العينات المدعمة بالياف الزجاج فقط والعينات المدعمة بنسبة 15% ألياف زجاج مع الحشوات السيراميكية المختلفة وان مقاومة البليان للعينات المحتوية على حشوات سيراميكية تكون اعلى من العينات المدعمة بالياف زجاجية فقط وان مقاومة البليان لمجموعة العينات المقواة بألياف زجاج مع كرانيت بلغت اعلى قيمة لها تليها ألعينات المدعمة بالبرلايت ثم عينات كاربونات الكالسيوم. نستنتج من ذالك إضافة الحشوات السيراميكية مع ألياف الزجاج يحسن بشكل كبير من مقاومة البليان.


Article
Effect of addition ZrO2-Al2O3 nanoparticles mixture on some properties and denture base adaptation of heat cured acrylic resin denture base material

Authors: Ali MA Aljafery --- Basima MAH
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2015 Volume: 27 Issue: 3 Pages: 15-21
Publisher: Baghdad University جامعة بغداد

Loading...
Loading...
Abstract

Background: The PMMA polymer denture base materials are low mechanical properties, adaptation of the denturebase to underlying tissue is important for retention and stability of denture. The aim of the study was toevaluate theeffect of mixtureZrO2-Al2O3 nanoparticles on impact strength, transverse strength, hardness, roughness, denture baseadaptation of heat cured acrylic resin denture base material.Materials and methods: One hundred (100) specimens were prepared, the specimens were divided into five groups(20 specimens to each) according to the test type, each group was subdivided in to two subgroups (control andexperimental) each subgroup consist of 10 specimens, the experimental group included mixture of 2% (ZrO2-Al2O3ratio2:1) by weight. Theimpact strength was measured by Charpy's impact testing machine, the transversestrength was measured by Instron testing machine while the hardness was measured byshore D durometer androughness was measured by Profilometer. Denture base adaptation was measured by digital microscope andevaluated by computerized tomography (CT).Results: Highly significant increaseofimpact and transverse strength, non-significant increase ofhardness, significantincrease ofroughness andreduction of denture base adaptation (measured at 3 point A, B and C) occurred inexperimental groupwhen compared to control group. CT evaluation, gap between the denture base and mastercast (control and experimental groups) increased from the anterior to posterior side of palate and from the alveolarridge to the mid palatal line.Conclusion: The polymer nanocomposites had mechanical properties higher than neat PMMA at same time lessdenture base adaptation


Article
STUDY THE EFFECT OF THE PARTICLE SIZE ON MECHANICAL PROPERTIES OF PARTICULATE NATURAL COMPOSITE MATERIALS

Author: Israa Faisal Qhazi
Journal: Al-Qadisiyah Journal for Engineering Sciences مجلة القادسية للعلوم الهندسية ISSN: 19984456 Year: 2017 Volume: 10 Issue: 2 Pages: 120-132
Publisher: Al-Qadisiyah University جامعة القادسية

Loading...
Loading...
Abstract

This research studied the mechanical properties of particulates composite materials made from natural fillers (eggshell and sawdust) reinforced epoxy resin. The composite specimens were prepared by hand lay-up technique with one volume fraction Vf, and different particle size of fillers.Modulus of elasticity, tensile strength, percentage of elongation and hardness were measured for each type of composite. The tensile tests results had shown an incremental increase with size of particles decreasing also hardness results had shown an incremental increase with smaller particle size.This work institutes a good substitution for synthetics fillers avoiding their highly cost and their toxicity, at the same time reducing of the environmental pollution.


Article
The Influence of Silica Dioxide and Aluminum Oxide Nano Fillers Reinforced Heat Cured Acrylic Denture Base Material and Thermocycling on Tensile and Shear Bond to Denture Soft Lining Material

Author: Dr. Hikmat J. Al-Judy. B.D.S., M.Sc., Ph.D. د. حكمت جميل
Journal: MUSTANSIRIA DENTAL JOURNAL مجلة المستنصرية لطب الاسنان ISSN: 18138500 Year: 2017 Volume: 14 Issue: 1 Pages: 99-109
Publisher: Al-Mustansyriah University الجامعة المستنصرية

Loading...
Loading...
Abstract

Background: Soft lining materials play an important role in modern prosthodonticstreatment because of their capability to restore the inflamed and distorted mucosa.The purpose of the research was to estimate the influence of acrylic denture basereinforcement with silanted nano fillers (Al2O3 and Sio2) separately on tensile andshear bond strength of soft lining material and studying effect of thermo cyclingon bonding strength.Materials and methods: Total 120 specimens were prepared; it divided into 60Specimens for shear bond strength test and 6o specimens for tensile bond strengthtest. Specimens were sub grouped into 30 Specimens without thermo cycling and30 specimens with thermo cycling. Each sub group is consisted from: 10Specimens control, 10 specimens were reinforced with 2 wt% of Al2O3 nano fillersand 10 specimens were reinforced with 5 wt% of SiO2 nano fillers. Samples wereprocessed depending on test applied. Soft lining material was applied for eachtesting group. Samples were immersed in distal water for 24 hours at 37°C beforetesting. For thermo cycling test, specimen were thermo cycled in thermo cyclingdevice. Bonding strength test was done using INSTRON universal testingmachine.Results: reinforcement of acrylic denture base with nano-fillers was significantlyincrease both tensile and shear bonding of lining material and thermo cyclingdecreases both bonding strength.Conclusion: reinforcement of acrylic denture base with nano fillers could improvebonding strength of lining material, while thermo cycling had a deleterious effecton bonding strength.


Article
Preparation Nano Composite Material Used in Oil and Gas Pipelines

Authors: N.F.Ibraheem --- I.A.Esmael --- H.M.Yas
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2017 Volume: 35 Issue: 9 Part (A) Engineering Pages: 950-955
Publisher: University of Technology الجامعة التكنولوجية

Loading...
Loading...
Abstract

In this research a polymeric composites have been prepared using epoxy resin reinforced with fiber glass and two nano fillers silicon oxide SiO2 particle size around 35 nm and titanium dioxide TiO2 particle size around (100-150 nm). These composites have been prepared in square slices (25x25) cm and 8mm thickness, by saturating fiber glass mattresses in the liquid epoxy resin with nano fillers and then cutting the product in suitable shapes to conduct the mechanical tests highest properties (tensile strength, elongation, Flexural strength, hardness strength, and impact strength. were (116.1 N/mm2, 9.98%, 396 N/mm2, 83.8 shore-D and 5.8 J). The aim of this research is to prepare polymeric materials with high mechanical properties that can be used in many industrial applications especially in the manufacture of oil and gas pipe systems and crude oil pipelines.


Article
Effect of Fillers on the Adhesion Properties of the Cured Unsaturated Polyester Adhesive
تأثير المالئات على خواص اللصق للواصق البولي أسترات غير المشبعة المقساة

Authors: Adil K. Hussien عادل قادر حسين --- Sa'ad F. Mahmood سعد فاضل محمود
Journal: Rafidain journal of science مجلة علوم الرافدين ISSN: 16089391 Year: 2018 Volume: 27 Issue: 1E Pages: 65-72
Publisher: Mosul University جامعة الموصل

Loading...
Loading...
Abstract

Unsaturated polyester (UP) composed of maleic anhydride, phthalic anhydride and 1,2-propylene glycol has been prepared as an adhesive base component. Fillers are widely used in order to reduce cost and to control shrinkage in adhesive formulations. Four types of fillers of the same particle size (50 mesh) and different chemical properties, silica, alumina, talc, and kaolinwere used. The fillers were mixed with the unsaturated polyesterprepolymer in various contents (5, 10, 20, 30 and 40) part per hundred parts of resin (phr). Their effects on different adhesion properties have been investigated. Experimental results show, in general, that, the adhesion strength of the unsaturated polyester adhesive measured by the standard lap- shear test method (ASTM D-1002) was increased in accordance with the increase of the weight percentage of the loaded filler. Best results as an adhesion strength were obtained with the kaolin filler

حضر البولي استر غير المشبع الأولي (الذي يمثل المكون الأساسي لللاصق) من تفاعل انهيدريد الماليك و انهيدريدالفثاليك مع 2,1-بروبلين كلايكول. من مساوئ لواصق البولي استرات غير المشبعة هي الانكماش العالي نسبيا، لذلك تستخدم المالئات وعلى نطاق واسع لغرض خفض الكلفة والسيطرة على الانكماش في تراكيب لواصق البولي استرات غير المشبعة. استخدمت أربعة أنواع من المالئات ذوات صفات وتراكيب كيميائية مختلفة ولكن بحجم حبيبي واحد (50 mesh) هي السليكا والالومينا والتالك والكاؤولين وبنسب متفاوتة5, 10, 30, 20, 40 جزء لكل مائة جزء وزنا من الراتنج لغرض دراسة تأثيراتها على مختلف صفات الالتصاق. أظهرت نتائج قوة الالتصاق والتي أجريت قياساتها استنادا إلى طريقة فحص قوة القص القياسية الأمريكية (ASTM D-1002) حصول زيادة واضحة في قوة الالتصاق مع زيادة تراكيز المالئات المضافة وأن أفضل النتائج المستحصلة كانت مع الكاؤولين.

Keywords

Unsaturated Polyester --- Adhesive --- Fillers --- Silica --- Alumina --- Talc --- Kaolin

Listing 1 - 10 of 25 << page
of 3
>>
Sort by
Narrow your search

Resource type

article (25)


Language

English (17)

Arabic (4)

Arabic and English (4)


Year
From To Submit

2019 (1)

2018 (1)

2017 (6)

2016 (2)

2015 (4)

More...