Supercritical Carbon Dioxide as a Reaction Medium for the Zeolite-Catalyzed Alkylation of Naphthalene

2003 ◽  
Vol 42 (25) ◽  
pp. 6294-6302 ◽  
Author(s):  
Roger Gläser ◽  
Jens Weitkamp
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Reaction Medium ◽  
Supercritical Carbon

scholarly journals The Effect of Polymerization Temperature on the Properties of Polyvinyl Fluoride Polymerization in Supercritical Carbon Dioxide

2021 ◽  
Vol 2101 (1) ◽  
pp. 012063
Author(s):  
Wei Liu ◽  
Yanzhong Zhang ◽  
Huaiyun Chang ◽  
Rong Cai ◽  
Peiliang Ma
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Reaction Medium ◽  
Chemical Processes ◽  
Light Transmittance ◽  
Polymerization Temperature ◽  
Irregular Structure ◽  
Lower Melting Point ◽  
Application Fields ◽  
Supercritical Carbon

Abstract The ongoing search for environmentally friendlier alternative to the organic solvents used in chemical processes has led to the development of technologies based on supercritical carbon dioxide (scCO2), which is non-flammable, non-toxic and relatively inert fluid. Polymer chemistry does not escape this trend. Fluoropolymers prepared in scCO2 have many special properties, which are different from fluoropolymers that use water as the reaction medium, this paper studies the effect of polymerization temperature on polyvinyl fluoride polymerization in supercritical carbon dioxide. The results show that as the polymerization temperature increases, the intrinsic viscosity and shear viscosity of the polymer gradually decreases; at the same time, the increasing of polymerization temperature leads to higher proportion of irregular structure of the polymer, which causes lower melting point and lower crystallinity, and the film prepared by the resin also exhibits a higher visible light transmittance. The above results show that the resin polymerized in supercritical carbon dioxide can impart better performance to conventional polymerization, which expands the potential application fields of the resin.

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