Dynamic characterization of structural relaxation in V2O5–P2O5 bulk oxide glass

2019 ◽  
Vol 21 (27) ◽  
pp. 14879-14886
Author(s):  
Shaolai Wu ◽  
Debo Wang ◽  
Yuyong Zhong ◽  
Xiaohui Fang ◽  
Yongjun Chen ◽  
...  

The characteristic changes and the complete relaxation process of V2O5–P2O5 oxide glass are studied by dynamic thermal-mechanical analysis and differential scanning calorimetry.

1986 ◽  
Vol 76 ◽  
Author(s):  
C. W. Wilkins ◽  
H. E. Bair ◽  
M. G. Chan ◽  
R. S. Hutton

ABSTRACTWe have studied some of the physical and mechanical properties of cyclized polybutadiene (CBR) dielectrics by dynamic mechanical analysis, thermal mechanical analysis, thermogravimetry, infrared analysis, and differential scanning calorimetry. Of interest is the difference in properties between thin (<30 μm) films which have been cured under vacuum and those which have been cured in air. Our results indicate that curing under vacuum prevents oxidation and reduces crosslinking. Vacuum cured films have 20% smaller moduli and 200 lower glass transition temperature than do films produced in air.


2007 ◽  
Vol 121-123 ◽  
pp. 1419-1424 ◽  
Author(s):  
S. Tsantzalis ◽  
P. Tsotra ◽  
P. Karapappas ◽  
A. Vavouliotis ◽  
N. Fanis ◽  
...  

Vapor growth carbon nanofibers (CNFs), lead zirconate titanate piezoelectric (PZT) particles, as well as a combination of these two were added in an epoxy resin (EP), and their influence on the curing reaction was investigated. Moreover, the cured samples were characterised by dynamic scanning calorimetry and dynamic thermal mechanical analysis. The presence of the fillers had no significant effect of the curing reaction of the EP system and the glass transition temperature, Tg.


2003 ◽  
Vol 767 ◽  
Author(s):  
A. Tregub ◽  
G. Ng ◽  
M. Moinpour

AbstractSoak of polyurethane-based CMP pads in tungsten slurry and de-ionized water and its effect on retention of thermal and mechanical properties of the pads was studied using Dynamic Mechanical Analysis (DMA), Thermal Mechanical Analysis (TMA), Thermal Gravimetric Analysis (TGA), and Modulated Differential Scanning Calorimetry (MDSC). Simultaneous cross-linking and plastisizing due to soak were established using DMA and MDSC analysis. The stable operating temperature range and its dependence on soak time were determined using TMA analysis. Substantial difference in diffusion behavior of the “soft” and “hard” pads was discovered: diffusion into the hard pads followed Fickian law [1], while diffusion into the multi-layer soft pads was dominated by the fast filling of the highly porous pad surface with liquid.During a traditional CMP process, which involves application of polishing pads and slurry, the pad properties can be substantially and irreversibly changed as the result of slurry/rinse water absorption.The retention of the pad properties after exposure was monitored using such thermal and mechanical techniques, as Thermal Mechanical Analysis (TMA), Dynamical Mechanical Analysis (DMA), Modulated Differential Scanning Calorimetry (MDSC), Thermal Gravimetric Analysis (TGA).


2009 ◽  
Vol 24 (3) ◽  
pp. 1087-1092 ◽  
Author(s):  
Harsha P. Kulkarni ◽  
Gregory Mogilevsky ◽  
William M. Mullins ◽  
Yue Wu

A unique atomic force microscope-based local thermal-mechanical analysis (LTA) technique was used to study the influence of room temperature aging on viscoelastic properties of ethylene-methacrylic (E/MAA) acid ionomers. This approach permits easy access to structural relaxation effects on viscoelasticity at a short aging time, for instance, before the occurrence of secondary crystallization differential scanning calorimetry (DSC) melting peak. A Burger model along with finite element method yields quantitative analysis of viscoelastic properties versus the aging time. Creep curves were obtained with LTA after various times of aging at room temperature upon cooling from the melt. Measurements were carried out at both 30 and 70 °C. The results reveal the effects of structural relaxation upon aging in the ion-rich amorphous region, the influence of secondary crystallites on the viscoelastic properties, and shed light on the processes associated with aging in E/MAA ionomers.


Author(s):  
B. M. Culbertson ◽  
M. L. Devinev ◽  
E. C. Kao

The service performance of current dental composite materials, such as anterior and posterior restoratives and/or veneer cements, needs to be improved. As part of a comprehensive effort to find ways to improve such materials, we have launched a broad spectrum study of the physicochemical and mechanical properties of photopolymerizable or visible light cured (VLC) dental composites. The commercially available VLC materials being studied are shown in Table 1. A generic or neat resin VLC system is also being characterized by SEM and TEM, to more fully understand formulation variables and their effects on properties.At a recent dental research meeting, we reported on the differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) characterization of the materials in Table 1. It was shown by DSC and DMA that the materials are substantially undercured by commonly used VLC techniques. Post curing in an oral cavity or a dry environment at 37 to 50°C for 7 or more hours substantially enhances the cure of the materials.


2020 ◽  
Vol 17 (4) ◽  
pp. 303-311
Author(s):  
Roberta Cassano ◽  
Federica Curcio ◽  
Delia Mandracchia ◽  
Adriana Trapani ◽  
Sonia Trombino

Aim: The work’s aim was the preparation and characterization of a hydrogel based on gelatin and glycerine, useful for site-specific release of benzydamine, an anti-inflammatory drug, able to attenuate the inflammatory process typical of the vaginal infection. Objective: The obtained hydrogel has been characterized by Electronic Scanning Microscopy (SEM) and Differential Scanning Calorimetry (DSC). In addition, due to the precursor properties, the hydrogel exhibits a relevant mucoadhesive activity. Methods: The swelling degree was evaluated at two different pHs and at defined time intervals. In particular, phosphate buffers were used at pH 6.6, in order to mimic the typical conditions of infectious diseases at the vaginal level, particularly for HIV-seropositive pregnant women, and pH 4.6, to simulate the physiological environment. Results: The obtained results revealed that the hydrogel swells up well at both pHs. Conclusion: Release studies conducted at both pathological and physiological pHs have shown that benzydamine is released at the level of the vaginal mucosa in a slow and gradual manner. These data support the hypothesis of the hydrogel use for the site-specific release of benzydamine in the vaginal mucosa.


Author(s):  
Kinga Tamási ◽  
Kálmán Marossy

AbstractThe paper deals with the study of seven selected natural plant oils. Differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and thermally stimulated discharge (TSD) methods were used. It has been found that most of the oils tested are in a glassy state at low temperature and have multiple transitions in the low temperature range. DSC shows complex melting-like processes or glass transition. For both DMA and TSD, the scaffold supportive method was used and found as a suitable one. DMA and TSD proved more sensitive than DSC and revealed at least two transitions between − 120 and − 40 °C. In the case of three oils (argan, avocado and sunflower), current reversal was observed by TSD; this symptom cannot be fully explained at the moment.


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