From 03/18/2015 to 6/8/2012
Polymerization: Patent Titles
Polymerization: Patent Abstracts
Free Radical Polymerization
Polypropylene (PP) Polymerization
“In polymer chemistry, polymerization is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many forms of polymerization and different systems exist to categorize them.
In chemical compounds, polymerization occurs via a variety of reaction mechanisms that vary in complexity due to functional groups present in reacting compounds and their inherent steric effects explained by VSEPR Theory. In more straightforward polymerization, alkenes, which are relatively stable due to bonding between carbon atoms, form polymers through relatively simple radical reactions; in contrast, more complex reactions such as those that involve substitution at the carbonyl group require more complex synthesis due to the way in which reacting molecules polymerize.
As alkenes can be formed in somewhat straightforward reaction mechanisms, they form useful compounds such as polyethylene and polyvinyl chloride (PVC) when undergoing radical reactions, which are produced in high tonnages each year due to their usefulness in manufacturing processes of commercial products, such as piping, insulation and packaging. In general, polymers such as PVC are referred to as "homopolymers," as they consist of repeated long chains or structures of the same monomer unit, whereas polymers that consist of more than one molecule are referred to as copolymers (or co-polymers).
Other monomer units, such as formaldehyde hydrates or simple aldehydes, are able to polymerize themselves at quite low temperatures (>−80 °C) to form trimers; molecules consisting of 3 monomer units, which can cyclize to form ring cyclic structures, or undergo further reactions to form tetramers, or 4 monomer-unit compounds. Further compounds either being referred to as oligomers in smaller molecules. Generally, because formaldehyde is an exceptionally reactive electrophile it allows nucleophillic addition of hemiacetal intermediates, which are in general short-lived and relatively unstable "mid-stage" compounds that react with other molecules present to form more stable polymeric compounds.
Polymerization that is not sufficiently moderated and proceeds at a fast rate can be very hazardous. This phenomenon is known as Hazardous polymerization and can cause fires and explosions.”
(Wikipedia, Polymerization, 6/8/2012)
“The classical parameters which are relevant when setting up a polymerization process are the composition of the polymer, the reaction temperature, the viscosity, the reaction pressure, concentration ratios of the reactants, the pH in the case of aqueous systems, the molecular weight distribution and the particle size of a heterophase polymer. Other process-relevant quantities derivable from the process are the heat transfer coefficient, the mixing time, the degree of dispersing, shear load and maximum shear stress and the power input. It should be understood here that the first-mentioned parameters rather characterize the polymeric product while the process-relevant quantities on the other hand describe and characterize the process and the process control. Reliable process control, in particular in relatively large reaction containers, ensures that the reaction product is obtained exactly with said and required product properties.” [Gubaydullin et al US Patent 8,188,197 (5/29/2012)]
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Roger D. Corneliussen
Maro Polymer Links
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Copyright 2012 by Roger D. Corneliussen.
No part of this transmission is to be duplicated in any manner or forwarded by electronic mail without the express written permission of Roger D. Corneliussen
* Date of latest addition; date of first entry is 6/8/2012.