scholarly journals High temperature-gradient refractive index liquid crystals

2004 ◽  
Vol 12 (9) ◽  
pp. 2002 ◽  
Author(s):  
Jun Li ◽  
Sebastian Gauzia ◽  
Shin-Tson Wu
Keyword(s):  
Refractive Index ◽  
High Temperature ◽  
Liquid Crystals ◽  
Temperature Gradient ◽  
High Temperature Gradient ◽  
Gradient Refractive Index

High-temperature gradient HPLC and LC-NMR for the analysis of complex polyolefins

2008 ◽  
Vol 80 (8) ◽  
pp. 1747-1762 ◽  
Author(s):  
Harald Pasch ◽  
Lars-Christian Heinz ◽  
Tibor Macko ◽  
Wolf Hiller
Keyword(s):  
High Temperature ◽  
Chemical Composition ◽  
Temperature Gradient ◽  
Molar Mass ◽  
Size Exclusion ◽  
Copolymer Composition ◽  
Composition Distribution ◽  
High Temperature Gradient ◽  
Chemical Composition Distribution ◽  
On Line

The synthesis and characterization of polyolefins continues to be one of the most important areas for academic and industrial polymer research. One consequence of the development of new "tailor-made" polyolefins is the need for new and improved analytical techniques for the analysis of polyolefins with respect to molar mass and chemical composition distribution. The present article briefly reviews different new and relevant techniques for polyolefin analysis. Crystallization analysis fractionation is a powerful new technique for the analysis of short-chain branching in linear low-density polyethylene (LLDPE) and the analysis of polyolefin blends and copolymers regarding chemical composition. For the fast analysis of the chemical composition distribution, a new high-temperature gradient high-performance liquid chromatography (HPLC) system has been developed. The efficiency of this system for the separation of various olefin copolymers is demonstrated. The correlation between molar mass and chemical composition can be accessed by on-line coupling of high-temperature size exclusion chromatography (HT-SEC) and 1H NMR spectroscopy. It is shown that the on-line NMR analysis of chromatographic fractions yields information on microstructure and tacticity in addition to molar mass and copolymer composition.

scholarly journals High temperature gradient nanogap-Pirani micro-sensor with maximum sensitivity around atmospheric pressure

2017 ◽  
Vol 111 (11) ◽  
pp. 113502 ◽  
Author(s):  
C. Ghouila-Houri ◽  
A. Talbi ◽  
R. Viard ◽  
M. Moutaouekkil ◽  
O. Elmazria ◽  
...  
Keyword(s):  
High Temperature ◽  
Temperature Gradient ◽  
Atmospheric Pressure ◽  
Maximum Sensitivity ◽  
High Temperature Gradient ◽  
Micro Sensor
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