scholarly journals Viscoelastic Properties of Contemporary Bulk-fill Restoratives: A Dynamic-mechanical Analysis

2018 ◽  
Vol 43 (3) ◽  
pp. 307-314 ◽  
Author(s):  
JEX Ong ◽  
AU Yap ◽  
JY Hong ◽  
AH Eweis ◽  
NA Yahya
Keyword(s):  
Dynamic Mechanical Analysis ◽  
Storage Modulus ◽  
Loss Tangent ◽  
Viscoelastic Properties ◽  
Loss Modulus ◽  
Artificial Saliva ◽  
Mechanical Analysis ◽  
Distilled Water ◽  
Glass Ionomer ◽  
Dynamic Mechanical

SUMMARY This study investigated the viscoelastic properties of contemporary bulk-fill restoratives in distilled water and artificial saliva using dynamic mechanical analysis. The materials evaluated included a conventional composite (Filtek Z350), two bulk-fill composites (Filtek Bulk-fill and Tetric N Ceram), a bulk-fill giomer (Beautifil-Bulk Restorative), and two novel reinforced glass ionomer cements (Zirconomer [ZR] and Equia Forte [EQ]). The glass ionomer materials were also assessed with and without resin coating (Equia Forte Coat). Test specimens 12 × 2 × 2 mm of the various materials were fabricated using customized stainless-steel molds. After light polymerization/initial set, the specimens were removed from the molds, finished, measured, and conditioned in distilled water or artificial saliva at 37°C for seven days. The materials (n=10) were then subjected to dynamic mechanical testing in flexure mode at 37°C and a frequency of 0.1 to 10 Hz. Storage modulus, loss modulus, and loss tangent data were subjected to normality testing and statistical analysis using one-way analysis of variance/Dunnett's test and t-test at a significance level of p < 0.05. Mean storage modulus ranged from 3.16 ± 0.25 to 8.98 ± 0.44 GPa, while mean loss modulus ranged from 0.24 ± 0.03 to 0.65 ± 0.12 GPa for distilled water and artificial saliva. Values for loss tangent ranged from 45.7 ± 7.33 to 134.2 ± 12.36 (10−3). Significant differences in storage/loss modulus and loss tangent were observed between the various bulk-fill restoratives and two conditioning mediums. Storage modulus was significantly improved when EQ and ZR was not coated with resin.

Damping Factor and Dynamic Mechanical Analysis of Glass Fibre Reinforced Polyester Composite

2019 ◽  
Vol 11 (3) ◽  
Author(s):  
G. Sathishkumar ◽  
R. Sridhar ◽  
S. Sivabalan ◽  
S. Joseph Irudaya Raja
Keyword(s):  
Dynamic Mechanical Analysis ◽  
Storage Modulus ◽  
Glass Fibre ◽  
Loss Modulus ◽  
Fibre Length ◽  
Mechanical Analysis ◽  
Fibre Content ◽  
Damping Factor ◽  
Dynamic Mechanical ◽  
Polyester Composite

This study aims to evaluate the result of experimental examination conducted on free vibration characteristics and dynamic mechanical analysis over a range of temperature and five different frequencies of short glass fibre polyester composite. The effect of temperature on the storage modulus, loss modulus, and damping efficiency (tan δ) is determined. Synthetic reinforced material is created in random fibre orientation using hand lay-up method by domination of fibre length (10mm) and weight percent (5, 10, 15, 20%). Improvement in the fibre content will make a rise in the natural frequency and the storage modulus is maximum when fibre content of 20wt. % is introduced to the composite materials in the temperature ranges of 300-800°C. The peak of loss modulus and damping curves were lowered with respect to the fibre content. The properties were compared with neat polyester.

scholarly journals Dynamic Mechanical Analysis and Three-Body Abrasive Wear Behaviour of Thermoplastic Copolyester Elastomer Composites

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Hemanth Rajashekaraiah ◽  
Sekar Mohan ◽  
Pramoda Kumari Pallathadka ◽  
Suresha Bhimappa
Keyword(s):  
Abrasive Wear ◽  
Dynamic Mechanical Analysis ◽  
Storage Modulus ◽  
Abrasion Resistance ◽  
Loss Modulus ◽  
Mechanical Analysis ◽  
Wear Behaviour ◽  
Dynamic Mechanical ◽  
Ptfe Composite ◽  
Three Body

Various amounts of short fibers (glass and carbon) and particulate fillers like polytetrafluoroethylene (PTFE), silicon carbide (SiC), and alumina (Al2O3) were systematically introduced into the thermoplastic copolyester elastomer (TCE) matrix for reinforcement purpose. The mechanical properties such as storage modulus, loss modulus, and Tanδby dynamic mechanical analysis (DMA) and three-body abrasive wear performance on a dry sand rubber wheel abrasion tester have been investigated. For abrasive wear study, the experiments were planned according toL27orthogonal array by considering three factors and three levels. The complex moduli for TCE hybrid composites were pushed to a higher level relative to the TCE filled PTFE composite. At lower temperatures (in the glassy region), the storage modulus increases with increase in wt.% of reinforcement (fiber + fillers) and the value is maximum for the composite with 40 wt.% reinforcement. The loss modulus and damping peaks were also found to be higher by the incorporation of SiC and Al2O3microfillers. The routine abrasive wear test results indicated that TCE filled PTFE composite exhibited better abrasion resistance. Improvements in the abrasion resistance, however, have not been achieved by short-fiber and particlaute filler reinforcements. From the Taguchi’s experimental findings, optimal combination of control factors were obtained for minimum wear volume and also predictive correlations were proposed. Further, the worn surface morphology of the samples was discussed.

scholarly journals Dynamic mechanical behavior of nano-ZnO reinforced dental composite

2019 ◽  
Vol 8 (1) ◽  
pp. 90-99 ◽  
Author(s):  
Shubham Mahna ◽  
Hemraj Singh ◽  
Sumit Tomar ◽  
Deep Bhagat ◽  
Amar Patnaik ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Loss Modulus ◽  
Artificial Saliva ◽  
Dynamic Mechanical Properties ◽  
Dental Composite ◽  
Distilled Water ◽  
Nano Zno ◽  
Dynamic Mechanical ◽  
Cold Drink

Abstract In the present work, Bisphenol-A Glycidyl Methacrylate / Triethylene Glycol Dimethylacrylate based dental composites filled with 0-30 wt.% silane treated nano-ZnO were fabricated and tested for their dynamic mechanical properties. Samples were kept in each of three different mediums such as cold drink, distilled water and saliva for 7 days. The dynamic mechanical properties such as storage modulus, loss modulus and Tan delta were evaluated and compared for each composite under different conditions. The finding of results indicated that on adding 30 wt.% nano-ZnO, the storage modulus was increased by 109% in case of post cured, 120% in case of cold drink, 125% in case of artificial saliva but decreased by 70% in case of distilled water. The loss modulus was increased by 175% in case of post cured, 30% in case of cold drink, 50% in case of artificial saliva but decreased by 50% in case of distilled water. Further, minimum value of storage modulus was reported in case of distilled water medium followed by cold drink and then artificial saliva. Also, cold drink seems to be better medium than distilled water in terms of dynamic mechanical properties of dental composite. Graphical abstract Variation of storage modulus of sample kept in artificial saliva for 7 days Addition of 30 wt.% nano-ZnO increased the storage modulus by 109% in case of post cured, 120% in case of cold drink, 125% in case of artificial saliva but decreased by 70% in case of distilled water. Addition of 30 wt.% nano-ZnO increased the loss modulus by 175% in case of post cured, 30% in case of cold drink, 50% in case of artificial saliva but decreased by 50% in case of distilled water. Immersion of sample in each medium led to decrease in storage modulus but increase in Tan delta. Further, minimum value of storage modulus was reported in case of distilled water medium followed by cold drink and then artificial saliva. Cold drink seems to be better medium than distilled water in terms of dynamic mechanical properties of dental composite.

Dynamic mechanical behaviour of kevlar and carbon-kevlar hybrid fibre reinforced polymer composites

2020 ◽  
pp. 095440622097060
Author(s):  
Pragati Priyanka ◽  
Harlal Singh Mali ◽  
Anurag Dixit
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Dynamic Mechanical Analysis ◽  
Storage Modulus ◽  
Composite Laminates ◽  
Mechanical Analysis ◽  
Textile Composites ◽  
Elastic Behaviour ◽  
Dynamic Mechanical

Comprehensive experimental results of dynamic mechanical analysis (DMA) of polymer reinforced textile composites are presented in the current investigation. Plain and 2x2 twill woven multilayer fabrics of monolithic kevlar and hybrid carbon-kevlar (C-K) are reinforced into the thermoset polymer matrix. Kevlar/epoxy and C-K/epoxy composite laminates are fabricated using an in-house facility of the vacuum-assisted resin infusion process. Variation of the visco-elastic behaviour (storage modulus, damping factor and glass transition temperature, Tg) along with time, temperature and frequency is studied for the composites. Dynamic mechanical analysis is performed under temperature sweep with frequency ranging from 1-50 Hz. Results depict the effect of inter yarn hybridisation of carbon with kevlar yarns on the storage modulus, damping performance, and creep behaviour of dry textile composites. Temperature swept dynamic characterisation is also performed to evaluate the degradation and damping performance of the composite laminates soaked in the deionised water at glass transition temperature Tg, ½ Tg, and ¾ Tg. The morphological study has been performed post the dynamic mechanical analysis using field emission scanning electron microscope.

Heat Built Up During Dynamic Mechanical Analysis (DMA) Testing of Rubber Specimens

2018 ◽  
Author(s):  
Roja Esmaeeli ◽  
Ashkan Nazari ◽  
Haniph Aliniagerdroudbari ◽  
Seyed Reza Hashemi ◽  
Muapper Alhadri ◽  
...  
Keyword(s):  
Dynamic Mechanical Analysis ◽  
Heat Generation ◽  
Temperature Rise ◽  
Viscoelastic Properties ◽  
Mechanical Analysis ◽  
Compression Tests ◽  
Element Analysis ◽  
Dynamic Mechanical ◽  
Fea Model ◽  
Static And Dynamic Moduli

The viscoelastic properties of rubbers play an important role in dynamic applications and are commonly measured and quantified by means of Dynamic Mechanical Analysis (DMA) tests. The rubber properties including the static and dynamic moduli are a function of temperature; and an increase in the temperature leads to a decrease in both moduli of the rubber. Due to the heat generation inside the rubber during the DMA test and the possible change of the rubber properties it is important to quantify the amount of temperature rise in the rubber specimen during the test. In this study, a Finite Element Analysis (FEA) model is used to predict the heat generation and temperature rise during the rubber DMA tests. This model is used to identify the best shape of the specimen to achieve the minimum increase in temperature during the test. The double sandwich shear test and the cyclic compression tests are considered in this study because these two tests are mostly used in industry to predict the rubber viscoelastic properties.

scholarly journals Dynamic Mechanical Analysis as a Complementary Technique for Stickiness Determination in Model Whey Protein Powders

Foods ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1295
Author(s):  
Laura O’Donoghue ◽  
Md. Haque ◽  
Sean Hogan ◽  
Fathima Laffir ◽  
James O’Mahony ◽  
...  
Keyword(s):  
Glass Transition ◽  
Dynamic Mechanical Analysis ◽  
Whey Protein ◽  
Loss Modulus ◽  
Mechanical Analysis ◽  
Whey Protein Concentrate ◽  
Scanning Calorimetry ◽  
Dynamic Mechanical ◽  
Storage And Loss Moduli ◽  
Lower Protein

The α-relaxation temperatures (Tα), derived from the storage and loss moduli using dynamic mechanical analysis (DMA), were compared to methods for stickiness and glass transition determination for a selection of model whey protein concentrate (WPC) powders with varying protein contents. Glass transition temperatures (Tg) were determined using differential scanning calorimetry (DSC), and stickiness behavior was characterized using a fluidization technique. For the lower protein powders (WPC 20 and 35), the mechanical Tα determined from the storage modulus of the DMA (Tα onset) were in good agreement with the fluidization results, whereas for higher protein powders (WPC 50 and 65), the fluidization results compared better to the loss modulus results of the DMA (Tα peak). This study demonstrates that DMA has the potential to be a useful technique to complement stickiness characterization of dairy powders by providing an increased understanding of the mechanisms of stickiness.

The effect of yield damage on the viscoelastic properties of cortical bone tissue as measured by dynamic mechanical analysis

2007 ◽  
Vol 82A (3) ◽  
pp. 530-537 ◽  
Author(s):  
Yener N. Yeni ◽  
Richard R. Shaffer ◽  
Kevin C. Baker ◽  
X. Neil Dong ◽  
Michele J. Grimm ◽  
...  
Keyword(s):  
Dynamic Mechanical Analysis ◽  
Cortical Bone ◽  
Bone Tissue ◽  
Viscoelastic Properties ◽  
Mechanical Analysis ◽  
Dynamic Mechanical

Comparative investigation of physical, mechanical and thermomechanical characterization of dental composite filled with nanohydroxyapatite and mineral trioxide aggregate

e-Polymers ◽  
2017 ◽  
Vol 17 (4) ◽  
pp. 311-319 ◽  
Author(s):  
Anoj Meena ◽  
Harlal Singh Mali ◽  
Amar Patnaik ◽  
Shiv Ranjan Kumar
Keyword(s):  
Compressive Strength ◽  
Dynamic Mechanical Analysis ◽  
Storage Modulus ◽  
Water Sorption ◽  
Mineral Trioxide Aggregate ◽  
Mechanical Analysis ◽  
Comparative Investigation ◽  
Dental Composite ◽  
Dynamic Mechanical

AbstractThis study presents comparative investigation of adding nanohydroxyapatite (HA) (5–20 wt.%) and mineral trioxide aggregate (MTA) (5–20 wt.%) on the physical, mechanical and thermomechanical characterization of dental composite. The performances of both experimental composites were assessed through various physical, mechanical and thermomechanical tests such as void content test, microhardness test, compressive strength test, dynamic mechanical analysis and thermogravimetric analysis. The result of experiment indicated that the addition of 5 wt.% of HA increased the water sorption, hardness and compressive strength by 50.47%, 13.46% and 62.35%, respectively, whereas the addition of 5 wt.% of MTA increased the water sorption, hardness and compressive strength by 19.23%, 100% and 5.44%, respectively. Dynamic mechanical analysis results revealed that the addition of 5 wt.% HA increased the storage modulus by 10.21%, whereas the addition of 5 wt.% of MTA decreased the storage modulus by 11.79%. The filler HA proved to be better choice in term of thermal stability behavior as compare to MTA filler.

Sign in / Sign up

Export Citation Format

Share Document