In situ ultrasonic measurement of photoresist glass transition temperature

1998 ◽  
Vol 72 (19) ◽  
pp. 2457-2459 ◽  
Author(s):  
Susan L. Morton ◽  
F. Levent Degertekin ◽  
B. T. Khuri-Yakub
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Ultrasonic Measurement

scholarly journals X-ray reflectivity study of the glass transition temperature of thin films

2014 ◽  
Vol 70 (a1) ◽  
pp. C885-C885
Author(s):  
Krassimir Stoev ◽  
Kenji Sakurai
Keyword(s):  
Thin Films ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Amorphous Materials ◽  
Bulk Material ◽  
Grazing Incidence ◽  
X Ray ◽  
Surface And Interface

The glass transition takes place in amorphous materials (like polymers) during heating or cooling, and can be described as reversible transition from a hard and brittle state into a rubber-like state. Although physical properties of the material change significantly during the glass transition, this is not a phase transition of the material. The temperature at which the transition between the glassy and rubbery state occurs is called the glass transition temperature, and this temperature is always lower than the melting temperature. Thermodynamically, the glass transition is associated with transfer of heat between the system and its surrounding and with an abrupt volume change. Previously it was shown that the glass transition temperature of nano-films is different from that of bulk materials [1], which signifies the importance of determining this parameter for such systems. In the current work, we use quick X-ray reflectivity (qXRR) measurements to determine the glass transition temperature of polyvinyl acetate (PVAc). PVAc is rubbery synthetic polymer with the formula (C4H6O2), a density of 1.18 g/cm3, and a glass transition temperature for bulk material of 30oC [2]. Regular X-ray reflectivity measurements are based on θ/2θ scans at grazing incidence and typically require 0.5-1.5 h for a single scan. The qXRR technique is based on simultaneous measurement of the whole angular x-ray reflectivity profile and is suitable for in-situ measurement without moving the sample and/or the x-ray optics. Thus, the qXRR technique allows for very fast measurement of the x-ray reflectivity curves (duration of each scan is typically 0.1–20 sec [3]), which permits studying the time evolution of chemical, thermal, and mechanical changes at the surface and interface of different materials. X-ray reflectivity measurements give information about both density and thickness of thin films, and are suitable for studying glass transition phenomena. Nano-thickness PVAc layers on a Si substrate were examined with the qXRR technique, with x-ray reflectivity scans (each 10-seconds in duration) being recorded while temperature was changed from 20 to 50oC (total of 331 scans over 7 hours and 46 minutes). In the current paper, the experimental setup, the data-processing, and the analysis of the results from the qXRR measurements will be presented.

scholarly journals Improvement of mechanical properties of in situ-prepared HTPE binder in propellants

RSC Advances ◽  
2020 ◽  
Vol 10 (50) ◽  
pp. 30150-30161
Author(s):  
Keke Chen ◽  
Xiaomu Wen ◽  
Guoping Li ◽  
Siping Pang ◽  
Yunjun Luo
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Preparation Method

HTPE binder for propellant synthesized by in situ preparation method has excellent mechanical properties and low glass transition temperature.

Preparation of π-vi Semiconductor Nanocrystallites in a Glass Matrix Using Chalcogenizing Agent: Application to cdse

1994 ◽  
Vol 346 ◽  
Author(s):  
J.L. Marc ◽  
W. Gramer ◽  
A. Pradel ◽  
M. Ribes ◽  
T. Richard ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Glass Matrix ◽  
Sodium Borosilicate Glass ◽  
Electron Hole ◽  
Starting Solution ◽  
Crystallite Sizes ◽  
Size Dispersion

ABSTRACTA new route for preparing CdX (X = S, Se, Te, S+Se) nanocrystallites dispersed in a sodium borosilicate glass matrix from a hydrogel is proposed. Chalcogenizing complexing molecules - for instance a mixture of NH4SCN + H2SeO3 - introduced in the starting solution allowed an in situ crystallite preparation concomitant to gel densification. Prevention of crystallite oxidation is thus obtained. Moreover, coalescence is minimized because of the low gel-glass transition temperature. Low temperature absorption spectra have been interpreted in terms of exciton and electron-hole confinements, accounting for both an intrinsic broadening of energy states inside each nanocrystal and a Gaussian size distribution. Crystallite sizes and size dispersion can be adjusted by changing the initial Cd concentration. The crystallinity of the nanoparticles without change in dispersion is strongly improved by thermal treatment above the Tg of the glass matrix.

Preparation of self-promoted hydroxy-containing phthalonitrile resins by an in situ reaction

RSC Advances ◽  
2015 ◽  
Vol 5 (127) ◽  
pp. 105038-105046 ◽  
Author(s):  
Jianbo Wang ◽  
Jianghuai Hu ◽  
Ke Zeng ◽  
Gang Yang
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Hydroxy Group ◽  
High Modulus ◽  
High Glass Transition Temperature ◽  
One Pot ◽  
In Situ Reaction

The in situ reaction of a hydroxy group with a phthalonitrile system was carried out in a one-pot reaction and the prepared polymers showed outstanding thermal stability, a high modulus and a high glass transition temperature.

Analysis of Residual Stress Generated During Plasma Spraying of Glass Coatings

1998 ◽  
Author(s):  
Y. Bao ◽  
T. Zhang ◽  
D.T. Gawne
Keyword(s):  
Residual Stress ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Residual Stresses ◽  
Plasma Spraying ◽  
Experimental Measurements ◽  
Plasma Flame ◽  
Spraying Parameters

Abstract An investigation has been undertaken on the analysis of residual stress in glass coatings during plasma spraying. Theoretical analysis and in-situ experimental measurements show that the residual stresses in glass coatings are particularly sensitive to the heat input from the plasma flame, since this can raise the temperature to above the glass transition temperature. Control of the spraying parameters enables the quench stress of splats to be relaxed by the end of the spraying and the only significant remaining source of stress derives from the differential contraction between the coating and substrate during cooling. The analysis also shows that a stress transition occurs during cooling and that the sign of the final residual stress depends upon the expansion coefficient of the glass. The residual stresses are shown to govern the critical coating thickness for cracking and the coating adhesion.

In-Situ Temperature Monitoring of ABS During Fused Filament Fabrication (FFF) Process With Varying Process Parameters

2021 ◽  
Author(s):  
Youmna Mahmoud ◽  
Souran Manoochehri
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Temperature Measurement ◽  
Process Parameters ◽  
Transfer Model ◽  
Temperature Profiles ◽  
Fused Filament Fabrication ◽  
Bed Temperature

Abstract Fused Filament Fabrication (FFF) is presently one of the most commonly used Additive Manufacturing (AM) technology for various engineering applications. However, accuracy and stability remain a major challenge during AM processes. FFF is inherently a thermal process. So, it is important to analyze and monitor the temperature evolution of each deposited filament during and after printing. This work presents an in-situ temperature measurement setup with an infrared camera, used in collecting temperature profiles of printed layers. These temperature profiles were compared to a theoretical 1D heat transfer model, demonstrating good agreement between the two sets of data. The temperature measurement experiment has been repeated for different printing process parameters, namely print speed, flowrate, and bed temperature. The effect of fan cooling is also studied. These data play a significant role in determining the optimal settings needed to achieve the desired bonding between adjacent filaments. This can be concluded by studying the effect of changing the parameters on the cooling of each deposited filament concerning the material’s glass transition temperature. The average temperature of any two adjacent layers in a part has been evaluated and compared to the material’s glass transition temperature to provide a better insight on the quality of adhesion taking place. A visual inspection of the part has also been proven to be useful in evaluating the effect on the final quality.

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