Exploring a unified description of the super-Arrhenius region above and below the glass transition temperature

Soft Matter ◽  
2020 ◽  
Vol 16 (29) ◽  
pp. 6902-6913
Author(s):  
Georgios Kritikos
Keyword(s):  
Experimental Data ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
New Approach ◽  
Unified Description

A new approach to the description of the dynamics in the super-Arrhenius region is presented, in order to check whether the hypothesis of an Arrhenius component surviving in the α-relaxation region is consistent with experimental data.

Effect of Chain Morphology and Carbon-Nanotube Additives on the Glass Transition Temperature of Polyethylene

2013 ◽  
Vol 23 ◽  
pp. 16-23 ◽  
Author(s):  
S. Herasati ◽  
H.H. Ruan ◽  
Liang Chi Zhang
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Glass Transition ◽  
Carbon Nanotube ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Md Simulation ◽  
Md Simulations ◽  
Crystalline Polymers ◽  
Good Agreement

Glass transition temperature Tg is the most important parameter affecting the mechanical properties of amorphous and semi-crystalline polymers. However, the atomistic origin of glass transition is not yet well understood. Using Polyethylene (PE) as an example, this paper investigates the glass transition temperature Tg of PE with the aid of molecular dynamics (MD) simulation. The effects of PE chain branches, crystallinity and carbon-nanotube (CNT) additives on the glass transition temperature are analyzed. The MD simulations render a good agreement with the relevant experimental data of semi-crystalline PE and show the significant effects of crystallinity and addition of CNTs on Tg.

Moisture Sorption Isotherms, Isosteric Heat of Sorption and Glass Transition Temperature of Murtilla (Ugni molinae T.) Berry

2014 ◽  
Vol 10 (4) ◽  
pp. 583-594 ◽  
Author(s):  
Kong S. Ah-Hen ◽  
Roberto Lemus-Mondaca ◽  
Karen A. Mathias-Rettig ◽  
Antonio Vega-Gálvez ◽  
Jessica López
Keyword(s):  
Experimental Data ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Moisture Content ◽  
Sorption Isotherms ◽  
Isosteric Heat ◽  
Sorption Data ◽  
Heat Of Sorption ◽  
Ugni Molinae

Abstract Adsorption and desorption isotherms of fresh and dried murtilla (Ugni molinae Turcz) berries were determined at 20, 40 and 60°C using a gravimetric technique. The experimental data obtained were fitted to eight models, namely GAB, BET, Henderson, Caurie, Smith, Oswin, Halsey and Iglesias–Chirife. A non-linear least square regression analysis was used to evaluate the models. The GAB model best fitted the experimental data. Isosteric heat of sorption was determined from the equilibrium sorption data using the Clausius–Clapeyron equation and was found to decrease exponentially with increasing moisture content. The enthalpy–entropy compensation theory applied to the sorption isotherms indicated an enthalpy controlled sorption process. Glass transition temperature of murtilla was determined by differential scanning calorimetry and modelled as a function of moisture content by the Gordon–Taylor equation and as function of water activity by Roos and Khalloufi models, which proved to be excellent tools for predicting glass transition of murtilla.

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