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Topic: Polymerization

Related Topics

Polymer

Condensation polymer

Polymer physics

Free radical

Emulsion polymerization

Polydispersity index

Monomer

Plasma polymerization

Repeating unit

Radical initiator

Condensation reaction

Bond dissociation energy

Polyethylene

Polyethene

Synthetic rubber

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	Experimental Investigations in Polymerization Kinetics
		This requires the measurement of the overall rate of polymerization as a function of monomer concentration; accordingly varying amounts of monomer had to be replaced by an inert solvent.
		With respect to polymerization kinetics they have a lot in common with normal emulsion polymerization the most characteristic feature of which is their ability to "separate" the radicals growing in micelles or latex particles from each other thus suppressing termination to a high extent and -- as a consequence -- providing high rates of polymerization.
		The site of polymerization in emulsions and microemulsions are (at least to predominantly) these micelles and (micro-)latex particles where according to the specific recipe of preparing microemulsions the various concentrations (monomer, coemulsifier, partly also solvent) are not really known with confidence.
	www.univie.ac.at /mmphc/pp_exp.html (3336 words)

	CiteULike: Enhanced polymerization of polar macromolecules by an applied electric field with application to mitosis. (Site not responding. Last check: 2007-11-05)
		Numerous cellular processes are characterized by the rapid polymerization of protein molecules to form rod-like structures.
		In this theoretical study, the relative probability of polymerization of a polar protein species is calculated in the presence and absence of an electric field.
		This mechanism is applied to the mitotic spindle structure, and by assuming that the spindle poles become oppositely charged during mitosis, a finite difference method is used to calculate the spindle structure at metaphase.
	www.citeulike.org /user/rubendrr/article/388943 (449 words)

	Polymerization
		Polymerization in the petroleum industry is the process of converting light olefin gases including ethylene, propylene, and butylene into hydrocarbons of higher molecular weight and higher octane number that can be used as gasoline blending stocks.
		Polymerization combines two or more identical olefin molecules to form a single molecule with the same elements in the same proportions as the original molecules.
		Polymerization may be accomplished thermally or in the presence of a catalyst at lower temperatures.
	www.setlaboratories.com /polymeri.htm (373 words)

	The MSDS HyperGlossary: Polymerization
		Polymerization is the process by which monomers (smaller chemical units) are combined to form a polymer.
		Polymerization of monomers is often an exothermic process (one that evolves heat).
		If polymerization begins when it is not desired, the result could be a fire or explosion.
	www.ilpi.com /msds/ref/polymer.html (332 words)

	Heterogeneous polymerization in carbon dioxide - Patent 5312882
		The heterogeneous polymerization of water-soluble polymer in CO.sub.2 is disclosed.
		The advantage of conducting the polymerization with supercritical CO.sub.2 inures from the tendency of the solvent strength of a solvent in a supercritical phase to be easily manipulated by varying the pressure of the fluid.
		Parameters varied between polymerization trials were the pressure of the reactor (97 or 345 bar), the initiator (either AIBN (155 mg--0.2 wt % to monomer) or the fluoro-azo initiator prepared in Example 3 (2.4 g)), and the presence or absence of the FOMA-styrene-FOMA surfactant prepared in Example 9.
	www.freepatentsonline.com /5312882.html (5262 words)

	Polymers
		He formulated a polymeric structure for rubber, based on a repeating isoprene unit (referred to as a monomer).
		Since a pi-bond in the monomer is converted to a sigma-bond in the polymer, the polymerization reaction is usually exothermic by 8 to 20 kcal/mol.
		Polymerization of isobutylene (2-methylpropene) by traces of strong acids is an example of cationic polymerization.
	www.cem.msu.edu /~reusch/VirtTxtJml/polymers.htm (4183 words)

	Mediated Radical Polymerization
		To fairly be termed "living" a polymerization must meet all these criteria since some are sensitive to certain characteristics of living polymerization while others are sensitive to other features.
		Because none of the reported mediated radical polymerizations may be legitimately described as living but, at the same time, have some of the characteristics of living polymerization, a great variety of terminology has sprung up to describe these processes including pseudo-living, quasi-living, etc.
		The term mediated radical polymerization (MRP) is not only descriptive of a wide range of radical polymerizations carried out in the presence of agents to modify the reactivity of the propagating species but avoids the confusion associated with the terms living free radical, living radical, controlled radical polymerization and the like.
	www.polyacs.org /nomcl/pmse.medrad.html (771 words)

	Bulk polymerization reactors patent invention
		A polymerization reactor having at least three side wall surfaces and a bottom wall surface forming a reservoir and at least one heat exchanger plate in fluid communication with a coolant source, wherein each of the at least one heat exchanger plate is disposed on a lid.
		An additional feature of the polymerization reactor is that the polymerization reactor may further comprise at least one coolant inlet manifold in fluid communication with the coolant source and at least one coolant outlet manifold in fluid communication with the coolant source.
		A further feature of the polymerization reactor is that the lid may include a plate hanger assembly disposed along the inner wall surface for attaching each of the at least one heat exchanger plates to the inner wall surface of the lid.
	www.freshpatents.com /Bulk-polymerization-reactors-dt20060817ptan20060182666.php (1288 words)

	[No title]
		After polymerization the polymer is generally recovered by washing the polymer containing solution with dilute, aqueous hydrogen chloride to neutralize the excess acid acceptor.
		This releases a strand from the C sheet and it is this strand that is replaced by the reactive loop of the second molecule in the dimer.
		This alternative mechanism of C sheet polymerization is not incompatible with the A sheet model, since the common first step in either polymerization process would be increased rate of refolding of the loop into the A sheet.
	www.lycos.com /info/polymerization--process.html (512 words)

	[No title]
		Although the physiological role for hsp70 polymerization by YDJ1 in ATP is not known, it is clear that this polymerization occurs in vitro.
		Polymerization of actin is correlated with hydrolysis of actin-bound ATP (Korn et al., 1987).
		In future studies on the mechanism of hsp70 polymerization by YDJ1, it will be important to correlate the ability of YDJ1 to activate the hsp70 ATPase activity with its ability to induce polymerization of hsp70.
	www.lycos.com /info/polymerization--actin-polymerization.html (411 words)

	Wikinfo \| Polymerization (Site not responding. Last check: 2007-11-05)
		Polymerization dates back to the beginning of DNA based life, as both DNA and proteins can be considered polymers.
		Another form of polymerization is ring-opening polymerization, which is similar to chain polymerization.
		Addition polymerization is involved in the manufacture of polymers such as polyethene, polypropylene and polyvinylchloride (PVC.) A special case of addition polymerization leads to living polymerization.
	www.wikinfo.org /wiki.php?title=polymerization (1140 words)

	History of Polymer & Plastic - Teacher Background Info (Site not responding. Last check: 2007-11-05)
		Polymerization can be demonstrated by linking strips of construction paper together to make paper garlands or hooking together hundreds of paper clips to form chains.
		Very simply, addition polymerization describes the process of "mers" joining by each one adding on to the end of the last "mer." A simple visual of the process is paper clips joined together to form a long chain.
		Polymeric dispersions, used to fill a mold are considered castings.
	www.teachingplastics.org /hands_on_plastics/intro_to_plastics/teachers.html (4969 words)

	The Polymerization of Ethylene under High Pressure using Semiconductor
		in 1931, during investigation of thermally initiated polymerization at low pressure, proposed that the step before the chemical reaction is the formation of a dimmer of ethylene.
		The heat of polymerization is high, and once it polymerizes 2-3 molecules of ethylene, the breaking of the C-C bound is possible.
		The heat transfer by convection in absence of polymerization and heat transfer by conduction through the reaction medium during polymerization shows that free electrons exist during the polymerization of ethylene under high pressure.
	www.journaloftheoretics.com /Articles/2-1/ZP-fp.htm (2190 words)

	Polymerization Reactions
		As a result, ionic polymerization reactions are relatively insensitive to temperature, and can be run at temperatures as low as -70°C. Ionic polymerization therefore tends to produce a more regular polymer, with less branching along the backbone, and more controlled tacticity.
		Ionic polymerization is therefore only used for monomers that don't polymerize by the free-radical mechanism or to prepare polymers with a regular structure.
		Free-radical polymerization of ethylene produces a low-density, branched polymer with side chains of one to five carbon atoms on up to 3% of the atoms along the polymer chain.
	chemed.chem.purdue.edu /genchem/topicreview/bp/1polymer/reactions.html (991 words)

	polymerization - Search Results - MSN Encarta
		Joining identical monomers to make carbon chains is called addition polymerization, because the process is similar to stringing many identical beads...
		Although some plastics are made from plant oils, the majority are made from fossil fuels.
		Two general methods exist for forming large molecules from small monomers: addition polymerization and condensation polymerization.
	encarta.msn.com /polymerization.html (102 words)

	Atom Transfer Radical Polymerization (Site not responding. Last check: 2007-11-05)
		Atom transfer radical polymerization is a controlled/“living” polymerization based on the use of radical polymerization to convert monomer to polymer.
		An alternative was sought because other types of living polymerizations are severely limited by many factors: only a small number of monomers can be used, the reactions are sensitive to moisture, and two or more monomers cannot be randomly copolymerized.
		It is capable of polymerizing a wide variety of monomers, is tolerant of trace impurities (water, oxygen, inhibitor), and is readily applicable to industrial processes.
	polymer.chem.cmu.edu /Center/ATRP.html (472 words)

	Polymerization Summary
		Chain polymerization is very rapid, and once a polymer is terminated, it will not react with monomers or other polymers.
		Polymerization is a process of reacting monomer molecules together in a chemical reaction to form three-dimensional networks or polymer chains
		Polymerization dates back to the beginning of DNA based life, as both DNA and proteins can be considered polymers.
	www.bookrags.com /Polymerization (703 words)

	PNAS -- Collected Resources : Polymerization Special Feature
		Polymerization Special Feature: Nuclearity and cooperativity effects in binuclear catalysts and cocatalysts for olefin polymerization
		Polymerization Special Feature: Diminishing catalyst concentration in atom transfer radical polymerization with reducing agents
		Polymerization Special Feature: Study of ligand substituent effects on the rate and stereoselectivity of lactide polymerization using aluminum salen-type initiators
	www.pnas.org /cgi/collection/polymerization (255 words)

	Condensation Polymerization
		The monomers that are involved in condensation polymerization are not the same as those in addition polymerization.
		Notice that at the beginning of the polymerization, the distribution lies farther to the right, meaning that there are a lot of monomers, dimers, trimers, and other short chains but few long chains.
		As the polymerization progresses, the distribution shifts to the left, indicating that there are fewer short chains and more of the longer ones.
	www.materialsworldmodules.org /resources/polimarization/4-condensation.html (1169 words)

	Role of hydrophobicity of phenylalanine beta 85 and leucine beta 88 in the acceptor pocket for valine beta 6 during ...
		Role of hydrophobicity of phenylalanine beta 85 and leucine beta 88 in the acceptor pocket for valine beta 6 during hemoglobin S polymerization -- Adachi et al.
		Role of hydrophobicity of phenylalanine beta 85 and leucine beta 88 in the acceptor pocket for valine beta 6 during hemoglobin S polymerization
		Kinetics of polymerization of Glu-beta 85 and Glu-beta 88
	www.jbc.org /cgi/content/abstract/269/50/31563 (468 words)

	Polymerization (Site not responding. Last check: 2007-11-05)
		Reaction kinetics are measured for the solution polymerization of methyl methacrylate in a batch reactor, showing basic techniques and how variables other than concentration can be used to measure kinetic parameters.
		The experiment forms the basis for a set of open ended assignments to examine the kinetic mechanism of a free radical chain growth polymerization reaction and the ramifications of physico-chemical phenomena which,may affect its performance in a continuous reactor.
		Polymerization in a dilatometer allows measurement of the volume change with time upon polymerization as the lower density monomer forms the higher density polymer.
	www-unix.ecs.umass.edu /~vanegmon/che402/polymerization.html (196 words)

	ICT - Catalytic Polymerization Processes
		Polymerization micro-reactor capable of detailed studies of polymer particle growth and morphology is constructed in our research group.
		This micro-reactor is going to be unique in its capability to control polymerization conditions and to dynamically monitor the dynamics of particle growth by several independent measurements.
		Systematic analysis of the stability of polymerization reactors is an actual problem due to the general trend of moving to shorter residence times and increasing the polymer production per hour.
	www.vscht.cz /homepage/english/main/research/industrial_projects/polymerization (478 words)

	Tubulin polymerization assay, fluorescence based (BK011)
		Polymerization is followed by fluorescence enhancement due to the incorporation of a fluorescent reporter into microtubules as polymerization occurs.
		It is based upon the fact that light is scattered by microtubules to an extent that is proportional to the concentration of microtubule polymer.
		Polymerization was measured by excitation at 360 nm and emission at 420 nm.
	www.cytoskeleton.com /products/biochem/bk011.html (491 words)

	Inline Polymerization Application
		The process starts with a low viscosity monomer (also used as a solvent to clean the reactor) mixed with a catalyst or a small amount of polymer.
		After agitation, polymerization is started by a catalyst being introduced to activate the polymerization.
		This information is used to control the polymerization progression.
	www.analyticalprocess.com /polymerization_applications.html (225 words)

	Principles of Polymerization, 4th Ed.
		Different methods of polymerization, reaction parameters for synthesis, molecular weight, branching and crosslinking, and the chemical and physical structure of polymers all receive ample coverage.
		The revised fourth edition of this classic text and reference includes new and expanded coverage on a multitude of topics, including: metallocene and post-metallocene polymerization catalysts; living polymerizations (radical, cationic, and anionic); dendrimer, hyperbranched, brush, and other polymer architectures and assemblies; graft and block copolymers; high-temperature polymers; conducting polymers; and more.
		Polymerization reactions are characterized as to their kinetic and thermodynamic features, their scope and utility for the synthesis of different types of polymer structures, and the process conditions which are used to carry them out...”
	www.polysurfacesbookstore.com /pages/3874.html (239 words)

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