Physicochemical Research of Clinically Retrieved CU-NI-TI Orthodontic Archwires

Abstract In modern orthodontics, thermally activated archwires are used more widely in clinical practice, because they have unique properties like superelasticity and bio-compatibility. The aim of the present study was to characterize commercial 35° C Cu-NiTi archwires in terms of their phase transition behavior, chemical composition, surface topography properties after clinical usage, as well as the influence of the autoclaving process. Materials and methods. 35° C Thermo-Active Copper NiTi (CuNiTi) of ORMCO, Glendora, CA, USA (as-received, as-received autoclaved and clinically retrieved) with rectangular cross-section and dimension 0.016x0.022 inch, were investigated. The physicochemical research was conducted via Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDX) and X-ray Diffraction Analysis (XRD). The autoclaving was done in Runyes model B autoclave. Results. The DSC results revealed the austenite start (9.8° C; 26.47° C) and austenite finish (28° C; 31.74° C) temperatures for the as-received and autoclaved archwires respectively. For clinically retrieved samples the austenite finish temperature (Af) is around 27° C. The XRD patterns of the as-received and clinically retrieved samples show almost identical diffraction patterns. Rough surface of the CuNiTi alloy was revealed by the SEM analysis. Autoclaving process seems to have no effects on archwires’ structure and chemical composition. Chemical content of the investigated as-received CuNiTi are Ni, Ti and Cu: 47.07 wt% and 46.81 wt% and 6.11 wt%, respectively. The autoclaving process seems to have little influence on the transition temperature. The results from our study showed little difference (~7 °C) in the finish transition temperatures (Af), compared to the manufacturer’s claim. No intermediate R phase was detected by DSC. Conclusion. A good knowledge of the structural changes that occur in CuNiTi alloys in the oral cavity is useful for the orthodontists in order to optimize orthodontic treatment.

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Preparation and Crystallization Kinetics of FeSiB Amorphous Ribbons under Non-Isothermal Regime

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.605.35 ◽

2014 ◽

Vol 605 ◽

pp. 35-38

Author(s):

Eirini Varouti

Keyword(s):

Thermal Stability ◽

Differential Scanning Calorimetry ◽

Chemical Composition ◽

Crystallization Kinetics ◽

Structural Changes ◽

Scanning Calorimetry ◽

Amorphous Ribbons ◽

Isothermal Regime ◽

Kinetics Of

The aim of the present work was the preparation and characterization of FeSiB amorphous magnetic ribbons with the following chemical composition: Fe80SixB20-x, x=5,6,8 and Fe75Si15B10. Differential Scanning Calorimetry was employed in order to study the thermal stability and structural changes during the transformations that took place. Much emphasis is placed on the analysis of the crystallization kinetics.

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Phase Polymorphism, Molecular Motions and Structural Changes in [Cr(NH3)6](ClO4)3

Zeitschrift für Naturforschung A ◽

10.1515/zna-2007-3-410 ◽

2007 ◽

Vol 62 (3-4) ◽

pp. 179-186 ◽

Cited By ~ 5

Author(s):

Edward Mikuli ◽

Natalia Górska ◽

Stanisław Wróbel ◽

Jacek Ściesińskic ◽

Ewa Ściesińska

Keyword(s):

Phase Transition ◽

Structural Changes ◽

Full Width ◽

Half Maximum ◽

Molecular Motions ◽

Scanning Calorimetry ◽

Phase Polymorphism ◽

Temperature Dependences ◽

Diffraction Patterns ◽

Fir Spectra

A phase transition in [Cr(NH3)6](ClO4)3 at Thc = 293.5 K (on heating) and Tcc = 293.0 K (on cooling) was determined by differential scanning calorimetry. The temperature dependences of the full width at half maximum of the bands connected with ρr(NH3)F1u and δd(ClO)E modes suggest that the discovered phase transition is not connected with drastic changes in the speed of reorientational motions of the NH3 ligands nor the ClO4 − anions. Temperature dependence of the FT-FIR spectra and the diffraction patterns show that the discovered phase transition is caused by a change in the crystal structure.

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Effect of Sonication Time and Clay Loading on Nanoclay Dispersion and Thermal Property of Epoxy-Clay Nanocomposite

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.471-472.490 ◽

2011 ◽

Vol 471-472 ◽

pp. 490-495 ◽

Cited By ~ 5

Author(s):

M.J. Adinoyi ◽

Necar Merah ◽

Zuhair M. Gasem ◽

N. Al-Aqeeli

Keyword(s):

Differential Scanning Calorimetry ◽

Sem Analysis ◽

Clay Nanocomposites ◽

Sonication Time ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

Clay Loading ◽

Polymer Clay Nanocomposite ◽

Nano Clay ◽

Xrd Patterns

The development of nanoclay-epoxy nanocomposite material requires a suitable blending process to be employed. Amongst blending techniques, sonication has been one of the promising means for polymer-clay nanocomposite fabrication. In this study, epoxy-clay nanocomposites with 2, 4 and 5% clay loadings were fabricated using different sonication periods ranging from 5 to 60 minutes. The effect of sonication time and clay loading on the nanocomposite structure was investigated using Differential Scanning Calorimetry (DSC), X-ray diffraction (XRD), Scanning Electron Micropscope (SEM) and Energy Dispersive Spectroscopy (EDS). Differential Scanning Calorimetry analysis indicated that while clay loading reduced the glass transition temperature (Tg), sonication time did not alter Tg significantly. Upon examining the structure of the resulting nanocomposites both exfoliation and intercalation structures were present, yet, neither structure was fully achieved; evident by the XRD patterns. Nonetheless, the predominant structures for most of the nanocomposites were intercalation. Intergallery spacing of the nanocomposites were enhanced with increased sonication time mainly at 2%wt loading; whereas further increase in nano-clay loading resulted in a reduction of the d-spacing. SEM analysis showed that clay agglomerates were present in the nanocomposites irrespective of the sonication time. However, the analysis revealed that dispersion of clay was better in the nanocomposite fabricated at higher sonication time. From the EDS analysis, the different sites in the nanocomposites’ microstructure were identified which were then correlated with the observation made in the fractographic analysis.

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Phase Transition and Thermochromism of the Hybrid (C12H25NH3)2FeCl4

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.111.55 ◽

2006 ◽

Vol 111 ◽

pp. 55-58

Author(s):

L.L. Guo ◽

Y.D. Dai ◽

H.X. Liu ◽

Shi Xi Ouyang

Keyword(s):

Phase Transition ◽

Structural Changes ◽

Energy Transition ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

Thermal Gravimetry ◽

Reversible Phase Transition ◽

Rotational Motions ◽

Xrd Patterns ◽

Reversible Phase

This paper focuses on the structural change and the thermochromism of the phase transition of the hybrid (C12H25NH3)2FeCl4. The temperature and the structures of the phase transition is investigated by a thermal gravimetry (TG) and differential scanning calorimetry (DSC), an infrared spectra (IR) and X-ray diffraction (XRD) patterns. The UV adsorption spectra account for the thermochromism. The results suggest that the reversible phase transition arises from the structural changes of the organic chains. The thermochromism is presumably due to the electrons redistribution on the levels and to the energy transition to translational and rotational motions of the organic chains.

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An Insight into the Correlation between Chemical Composition Changes of Aluminum-Iron-Polyphosphate Glasses and Thermal Properties

Materials ◽

10.3390/ma14082065 ◽

2021 ◽

Vol 14 (8) ◽

pp. 2065

Author(s):

Pawel Goj ◽

Aleksandra Wajda ◽

Agata Stoch ◽

Ireneusz Krakowiak ◽

Pawel Stoch

Keyword(s):

Thermal Properties ◽

Chemical Composition ◽

Melting Temperature ◽

Scanning Calorimetry ◽

Essential Information ◽

Radioactive Waste Immobilization ◽

Waste Immobilization ◽

Polyphosphate Glasses ◽

Diffraction Patterns ◽

Nuclear Waste Immobilization

The present study aimed to investigate the influence of the gradual substitution of Fe2O3 by Al2O3 on the thermal properties of polyphosphate glasses. The conducted considerations based on differential scanning calorimetry (DSC) and heating microscopy thermal analysis provided much essential information about the correlation between glass chemical composition and its characteristic parameters, such as transformation temperature, specific heat, crystallization temperature, crystallization enthalpy, the activation energy of crystal growth, melting temperature, and Angell glass thermal stability. The obtained estimation of viscosity changes as a function of temperature could be very helpful for researchers to correctly plan the vitrification process and thus radioactive waste immobilization. A precise analysis of DSC curves and X-ray diffraction patterns revealed the possibility of crystallization process design in order to create materials with different levels of crystallinity and phase composition. The drawn conclusions allow choosing the glass with the optimal concentration of Al2O3 and Fe2O3, which ensures the relatively low melting temperature, viscosity, and glass crystallization ability, with application potential in nuclear waste immobilization.

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Anisotropic radiation damage of potassium tetracyano platinate (KCP)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109100 ◽

1978 ◽

Vol 36 (1) ◽

pp. 392-393

Author(s):

N. Uyeda ◽

E. J. Kirkland ◽

B. M. Siegel

Keyword(s):

Electron Diffraction ◽

Radiation Damage ◽

Structural Changes ◽

High Resolution Electron Microscopy ◽

Radiation Sensitivity ◽

Resolution Electron ◽

Damage Process ◽

Diffraction Patterns ◽

Fading Rate

The direct observation of structural change by high resolution electron microscopy will be essential for the better understanding of the damage process and its mechanism. However, this approach still involves some difficulty in quantitative interpretation mostly being due to the quality of obtained images. Electron diffraction, using crystalline specimens, has been the method most frequently applied to obtain a comparison of radiation sensitivity of various materials on the quantitative base. If a series of single crystal patterns are obtained the fading rate of reflections during the damage process give good comparative measures. The electron diffraction patterns also render useful information concerning the structural changes in the crystal. In the present work, the radiation damage of potassium tetracyano-platinate was dealt with on the basis two dimensional observation of fading rates of diffraction spots. KCP is known as an ionic crystal which possesses “one dimensional” electronic properties and it would be of great interest to know if radiation damage proceeds in a strongly asymmetric manner.

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Preparation and properties of green rust type substances

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19870093 ◽

1987 ◽

Vol 52 (1) ◽

pp. 93-102 ◽

Cited By ~ 27

Author(s):

Jaroslav Vinš ◽

Jan Šubrt ◽

Vladimír Zapletal ◽

František Hanousek

Keyword(s):

Chemical Composition ◽

Electron Diffraction ◽

Green Rust ◽

X Ray ◽

Synthesis Conditions ◽

Diffraction Patterns

A method has been worked out for the reproducible preparation of Green Rust substances involving SO42-, Cl-, Br-, and I- anions. The chemical composition of the substances prepared has been followed in dependence on the synthesis conditions. The powder X-ray and electron diffraction patterns and infrared and Moessbauer spectra have been measured and discussed.

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The Effect of Surface Treatment with Isocyanate and Aromatic Carbodiimide of Thermally Expanded Vermiculite Used as a Functional Filler for Polylactide-Based Composites

Polymers ◽

10.3390/polym13060890 ◽

2021 ◽

Vol 13 (6) ◽

pp. 890

Author(s):

Mateusz Barczewski ◽

Olga Mysiukiewicz ◽

Aleksander Hejna ◽

Radosław Biskup ◽

Joanna Szulc ◽

...

Keyword(s):

Impact Strength ◽

Mechanical Stability ◽

Thermomechanical Analysis ◽

Thermomechanical Properties ◽

Phenyl Isocyanate ◽

Sem Analysis ◽

Scanning Calorimetry ◽

Melt Mixing ◽

Expanded Vermiculite ◽

Chain Extenders

In this work, thermally expanded vermiculite (TE-VMT) was surface modified and used as a filler for composites with a polylactide (PLA) matrix. Modification of vermiculite was realized by simultaneous ball milling with the presence of two PLA chain extenders, aromatic carbodiimide (KI), and 4,4’-methylenebis(phenyl isocyanate) (MDI). In addition to analyzing the particle size of the filler subjected to processing, the efficiency of mechanochemical modification was evaluated by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The composites of PLA with three vermiculite types were prepared by melt mixing and subjected to mechanical, thermomechanical, thermal, and structural evaluation. The structure of composites containing a constant amount of the filler (20 wt%) was assessed using FTIR spectroscopy and SEM analysis supplemented by evaluating the final injection-molded samples’ physicochemical properties. Mechanical behavior of the composites was assessed by static tensile test and impact strength hardness measurements. Heat deflection temperature (HDT) test and dynamic thermomechanical analysis (DMTA) were applied to evaluate the influence of the filler addition and its functionalization on thermomechanical properties of PLA-based composites. Thermal properties were assessed by differential scanning calorimetry (DSC), pyrolysis combustion flow calorimetry (PCFC), and thermogravimetric analysis (TGA). The use of filler-reactive chain extenders (CE) made it possible to change the vermiculite structure and obtain an improvement in interfacial adhesion and more favorable filler dispersions in the matrix. This translated into an improvement in impact strength and an increase in thermo-mechanical stability and heat release capacity of composites containing modified vermiculites.

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Dynamic Single-Fiber Pull-Out of Polypropylene Fibers Produced with Different Mechanical and Surface Properties for Concrete Reinforcement

Materials ◽

10.3390/ma14040722 ◽

2021 ◽

Vol 14 (4) ◽

pp. 722

Author(s):

Enrico Wölfel ◽

Harald Brünig ◽

Iurie Curosu ◽

Viktor Mechtcherine ◽

Christina Scheffler

Keyword(s):

Tensile Strength ◽

Dynamic Loading ◽

Melt Spinning ◽

Structural Changes ◽

High Surface ◽

Single Fiber ◽

Scanning Calorimetry ◽

Matrix Interaction ◽

Pull Out ◽

Fiber Matrix

In strain-hardening cement-based composites (SHCC), polypropylene (PP) fibers are often used to provide ductility through micro crack-bridging, in particular when subjected to high loading rates. For the purposeful material design of SHCC, fundamental research is required to understand the failure mechanisms depending on the mechanical properties of the fibers and the fiber–matrix interaction. Hence, PP fibers with diameters between 10 and 30 µm, differing tensile strength levels and Young’s moduli, but also circular and trilobal cross-sections were produced using melt-spinning equipment. The structural changes induced by the drawing parameters during the spinning process and surface modification by sizing were assessed in single-fiber tensile experiments and differential scanning calorimetry (DSC) of the fiber material. Scanning electron microscopy (SEM), atomic force microscopy (AFM) and contact angle measurements were applied to determine the topographical and wetting properties of the fiber surface. The fiber–matrix interaction under quasi-static and dynamic loading was studied in single-fiber pull-out experiments (SFPO). The main findings of microscale characterization showed that increased fiber tensile strength in combination with enhanced mechanical interlocking caused by high surface roughness led to improved energy absorption under dynamic loading. Further enhancement could be observed in the change from a circular to a trilobal fiber cross-section.

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Comparative Study of Structural Changes of Polylactide and Poly(ethylene terephthalate) in the Presence of Trichoderma viride

International Journal of Molecular Sciences ◽

10.3390/ijms22073491 ◽

2021 ◽

Vol 22 (7) ◽

pp. 3491

Author(s):

Grażyna B. Dąbrowska ◽

Zuzanna Garstecka ◽

Ewa Olewnik-Kruszkowska ◽

Grażyna Szczepańska ◽

Maciej Ostrowski ◽

...

Keyword(s):

Structural Changes ◽

Ethylene Terephthalate ◽

Molecular Mechanisms ◽

Blot Hybridization ◽

Trichoderma Viride ◽

Cost Effective ◽

Plastic Pollution ◽

Scanning Calorimetry ◽

Poly Ethylene Terephthalate ◽

Poly Ethylene

Plastic pollution is one of the crucial global challenges nowadays, and biodegradation is a promising approach to manage plastic waste in an environment-friendly and cost-effective way. In this study we identified the strain of fungus Trichoderma viride GZ1, which was characterized by particularly high pectinolytic activity. Using differential scanning calorimetry, Fourier-transform infrared spectroscopy techniques, and viscosity measurements we showed that three-month incubation of polylactide and polyethylene terephthalate in the presence of the fungus lead to significant changes of the surface of polylactide. Further, to gain insight into molecular mechanisms underneath the biodegradation process, western blot hybridization was used to show that in the presence of poly(ethylene terephthalate) (PET) in laboratory conditions the fungus produced hydrophobin proteins. The mycelium adhered to the plastic surface, which was confirmed by scanning electron microscopy, possibly due to the presence of hydrophobins. Further, using atomic force microscopy we demonstrated for the first time the formation of hydrophobin film on the surface of aliphatic polylactide (PLA) and PET by T. viride GZ1. This is the first stage of research that will be continued under environmental conditions, potentially leading to a practical application.

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