Polymer‐Melt Viscosity and the Glass Transition: An Evaluation of the Adam–Gibbs and the Free‐Volume Models

1968 ◽  
Vol 49 (3) ◽  
pp. 1393-1397 ◽  
Author(s):  
A. A. Miller
Keyword(s):  
Glass Transition ◽  
Free Volume ◽  
Polymer Melt ◽  
Melt Viscosity ◽  
Volume Models

scholarly journals A theoretical interpretation of free volume at glass transition

2017 ◽  
Vol 35 (11) ◽  
pp. 1415-1427 ◽  
Author(s):  
Yi-kun Ren ◽  
Yun-tao Li ◽  
Liang-bin Li
Keyword(s):  
Glass Transition ◽  
Free Volume ◽  
Theoretical Interpretation

Thermal Analysis of Nomex® and Kevlar® Fibers

1977 ◽  
Vol 47 (1) ◽  
pp. 62-66 ◽  
Author(s):  
J. R. Brown ◽  
B. C. Ennis
Keyword(s):  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Glass Transition ◽  
Melting Point ◽  
Transition Region ◽  
High Temperatures ◽  
High Performance ◽  
Polymer Melt ◽  
Glass Transition Region ◽  
Dta Curves

DTA, TG, and TMA curves of commercial Kevlar® 49 and Nomex® fibers have been used to assess their behavior at high temperatures. The fibers lost absorbed water around 100°C, and a glass transition was reflected in the DTA and TMA curves in the region of 300°C. Difficulties in the interpretation of DTA and TMA curves in the glass-transition region and in the assignments of Tv‘s for these high-performance fibers are discussed. Whereas Kevlar 49 showed both a crystalline melting point (560°C) and a sharp endothermal thermal decomposition (590°C), Nomex showed only the latter (440°C) and no evidence of melting from the DTA curves. The endothermal decomposition peaks apparently correspond to “polymer melt temperatures” reported for related materials, and correlate well with the TG and TMA features. During thermal analysis of Kevlar 49, oxidation occurs more readily than thermal decomposition, but the latter predominates for Nomex. Differences between dyed and undyed Nomex were due to differences in yarn constitution.

Determination of the pressure dependence of polymer melt viscosity using a combination of oscillatory and capillary rheometer

2019 ◽  
Vol 60 (3) ◽  
pp. 517-523 ◽  
Author(s):  
Sumanta Raha ◽  
Harindranath Sharma ◽  
M. Senthilmurugan ◽  
Sumanda Bandyopadhyay ◽  
Prasanta Mukhopadhyay
Keyword(s):  
Pressure Dependence ◽  
Polymer Melt ◽  
Capillary Rheometer ◽  
Melt Viscosity
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