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Topic: Living polymerization

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	Process for the living radical polymerization of chlorine containing monomers - United States Patent 6,838,535
		A polymeric composition comprising: a vinyl chlorine polymer derived from a living radical polymerization of a vinyl chloride monomer or a structurally-related derivative thereof in the presence of an initiator, a metal catalyst, an optional ligand and an optional solvent or water.
		A polymeric composition comprising: a vinyl chloride polymer derived from a radical polymerization of a vinyl chloride monomer or a structurally-related derivative in the presence of an initiator, a metal catalyst, and optionally ligand and optionally a solvent or water.
		A polymeric composition comprising: a copolymer derived from a radical or a living radical polymerization of vinyl chloride monomer or a structurally-related derivative and a comonomer known to copolymerize with vinyl chloride via a radical mechanism in the presence of an initiator, a metal catalyst, and optionally a ligand and optionally a solvent or water.
	xrint.com /patents/us/6838535 (10428 words)

	Direct synthesis by living cationic polymerization of nitrogen-containing polymers - Patent 5444135
		In the living polymerization process using an initiator having one functional nitrogen-containing group, the functionality of the polymer is close to the theoretical 1, and typically greater than 0.7.
		The living polymerization in accordance with the process of this invention is believed to proceed by the formation of an ion pair of the selected nitrogen-containing initiator and Lewis acid catalyst, followed by monomer insertion.
		The polymerization reaction may be conducted batchwise or in semicontinuous or continuous operation in which continuous streams of ingredients are delivered to the reactor, and an overflow of a slurry or solution of polymer is taken out for the recovery of the polymer therefrom.
	www.freepatentsonline.com /5444135.html (8189 words)

	Increased throughput in the manufacture of anionic polymers by reduction in polymer cement viscosity through the ...
		The living anionically polymerized polymer of claim 8, wherein the metal alkyl compound is selected from the group consisting of aluminum, zinc, boron, and magnesium alkyls having from 1 to 20 carbon atoms per alkyl substituent.
		The living anionically polymerized polymer of claim 8, wherein the metal alkyl compound is selected from the group consisting of triethylaluminum, trimethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum, trioctylaluminum, butylethyl-magnesium, di-n-butylmagnesium, di-n-hexylmagnesium, dimethylzinc, diethylzinc, di-n-propylzinc, diisobutylzinc, and di-n-butylzinc.
		The living anionically polymerized polymer of claim 8, wherein the organo substituent of the alkali metal compound is aliphatic, cycloaliphatic, aromatic, or alkyl-substituted aromatic.
	freepatentsonline.com /6492466.html (5236 words)

	IBM Research \| Almaden Research Center \| Science and Technology \| Polymer Science \| Living free radical polymerizations (Site not responding. Last check: 2007-10-22)
		In preparation, and to further this progress, our scientists are developing a wide range of techniques based on living polymerization methods, and in particular living free radical procedures to control and probe the effect of structure on the performance of these materials.
		Living free radical polymerization is a recently developed technique for the controlled polymerization of vinyl monomers; this field has witnessed rapid growth in recent years.
		The polymer brush was prepared by surface-initiated living free radical procedures.
	www.almaden.ibm.com /st/chemistry/ps/living (250 words)

	RAFT memorabilia; living radical polymerization in homogeneous and heterogeneous media
		Living radical polymerization represents a number of techniques which have drawn considerable scientific interest over the last few years, because they allow the preparation of complex polymer architectures in a relatively simple way and starting from a broad range of monomers.
		A more thorough kinetic analysis of the emulsion polymerization demonstrated that the shift of the radical chain length distribution towards lower values increases the radical exit rate leading to a slower polymerization, while also particle formation is hindered.
		This allowed living radical polymerizations to be conducted in a heterogeneous medium with the advantage of radical compartmentalization, leading to well-defined homopolymers (of methyl, butyl and 2-ethylhexyl methacrylate) but also allowed the preparation of 'designer-latices'.
	www.xs4all.nl /~engel13/hans/summary.html (890 words)

	Atom Transfer Radical Polymerization (Site not responding. Last check: 2007-10-22)
		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)

	Department of Chemistry - Faculty
		New Pd(II)-Based and Ni(II)-Based Catalysts for Polymerization of Ethylene and a-Olefins.
		The goals of this project have included the development living polymerization conditions such that polymer uniformity in molecular weight and molecular weight distribution could be controlled.
		Polymerization of a variety of olefins as well as copolymerization with polar monomers is being explored.
	www.chem.unc.edu /people/faculty/brookhartms/msbresproj.html (1159 words)

	Macromolecular Nomenclature Note No. 12
		Living polymerization was first defined by Szwarc(3) as a chain growth process without chain breaking reactions (transfer and termination).
		The term controlled is preferred to apparently living or "living" (with quotation marks) used to indicate synthesis of well-defined polymers under conditions in which chain breaking reactions undoubtedly occur, like in radical polymerization.
		Since chain breaking reactions are detected and quantitatively determined it was proposed to name these systems as apparently living or "living" (quotation marks refer to systems which were called living although chain breaking reactions were detected)(16,17) or controlled.
	www.polyacs.org /nomcl/mnn12.html (1942 words)

	High Density Polyethylene
		This high-pressure polymerization created polyethylene with many branches; the branches are created due to intermolecular and intramolecular chain transfer during polymerization.
		The mechanism for the polymerization of low-density polyethylene is free radical polymerization.
		Living polymerization means the polymerization continues until the concentration of ethylene runs out.
	www.eng.buffalo.edu /Courses/ce435/Polyethylene/CE435Kevin.htm (2108 words)

	Macromolecular Nomenclature Note No 19
		Later, the quotation marks were abandoned, and anionic polymerizations in the absence of elementary chain breaking reactions, such as termination and chain transfer, were called living polymerizations.
		Polymerization of a variety of epoxides and lactones induced by aluminum porphyrins in the presence of protic chain transfer agents (alcohols, acids) can occur in the absence of irreversible chain breaking reactions.
		Polymerizations are usually distinguished by the chemical nature of the propagating species, such as free radicals, anions, cations, and coordinative complexes.
	www.polyacs.org /nomcl/mnn19.html (3323 words)

	PCCM - Polymer Synthesis Lab
		This generally means that living anionic polymerization is the chemistry utilized for synthesis.
		Living anionic polymerization is used as the method of choice in model polymer synthesis due to its unique ability to produce well-defined materials with a reasonable choice of monomers.
		The term “living” refers to the nature of the propagating anion in the polymerization mechanism.
	www.princeton.edu /~pccm/facilities-polymersynth.htm (347 words)

	Expert: Polymer Synthesis and Structure Expert
		Expert has investigated the polymerization and copolymerization of acrylic and methacrylic monomers by free radical, group transfer, and pseudo-living polymerization methods.
		His work on vinyl polymerization includes bulk, solution, suspension, and emulsion polymerization techniques for the preparation of homopolymers, copolymers, block and graft copolymers, and ion-exchange resins.
		Expert is currently investigating new ways to prepare block copolymers using free radical polymerization chemistry and is particularly interested in developing thermoplastic elastomers with good solvent resistance, flame resistance, and high softening points.
	www.intota.com /viewbio.asp?bioID=603816&perID=107911 (714 words)

	Photocontrolled living polymerizations : Article : Nature Materials (Site not responding. Last check: 2007-10-22)
		The polymerization proceeds through attack of the initiator and propagating anion on the iron atom of the photoexcited monomer and, remarkably, the polymerization rate decreases with increasing temperature.
		As polymerization of 1 only occurs with photoexcitation of the monomer, initiation and propagation rates are expected to depend on this step.
		For example, attempts to polymerize acetylide-functionalized [1]ferrocenophane 4 by means of controlled methods, such as anionic polymerization initiated with n-butyl lithium, have been unsuccessful due to side reactions associated with the alkyne moieties.
	www.nature.com /nmat/journal/v5/n6/full/nmat1649.html (2685 words)

	The Primordial Soup Myth
		Taken together the evidence suggests that the first living thing was not a self replicating molecule, but rather a system of chemicals that contained the knowledge required to replicate, and the ability to couple this replication to an energy source.
		All of these factors imply that the first living thing was not that much simpler than life as it exists today.
		And the salt in the ocean once concentrated will prevent the polymerization of organic molcules (salt causes these molecules to precipitate out of solution so that they are no longer available for polymerization), so the picture below is not really the primordial soup.
	theory-of-evolution.net /chap11/primordial-soup-myth.php (937 words)

	New Living Radical Polymerization Method
		Chemists at the University of Pennsylvania have created a new process for free radical polymerization, the chemical reaction responsible for creating an enormous array of everyday plastic products, from Styrofoam cups to PVC tubing to car parts.
		Unlike the "traditional" method for living polymerization, which has been around for more than 50 years, this method takes place at room temperature, uses less metal catalyst to drive the reaction and requires a very short reaction time.
		This new technique, called Single Electron Transfer-Living Radical Polymerization, also offers chemists greater control over the molecular architecture of the polymers they create and allows them to use materials that did not work with the traditional process.
	www.azom.com /details_news.asp?newsID=6927 (486 words)

	Untitled Document
		Our work advances the idea that living polymerization techniques can be combined with a convergent method to synthesize hyperbranched polymers of low polydispersity and high degrees of branching through a greatly-simplified one-pot procedure.
		Specifically, the synthesis is done by first initiating and polymerizing a low molecular weight chain through living methods; the living end is then reacted with a compound having both a polymerizable group and a moiety capable of quantitatively coupling with the growing chain end.
		We have some examples of varied polymer compositions to make copolymers that are useful as novel thermoplastic elastomers with unique polymer morphologies studied by AFM and electron microscopy and materials with different functional groups at the core of the structure.
	www.mines.edu /fs_home/dknauss/DendriticPolymers.html (695 words)

	Penn Department of Chemistry - Faculty (Site not responding. Last check: 2007-10-22)
		Metallo-radical and organo-metal substrate reactions are used in both obtaining living radical polymerization for application in block copoymer materials and energy relevant small molecule organometallic transformations.
		This new approach to obtaining living radical polymerization occurs by a degenerative transfer pathway that involves rapid interchange of polymeric radicals in the polymer with polymeric units in the organo-cobalt porphyrin complexes.
		This pathway to obtain living radical polymerization is a transition metal form of degenerative transfer that we refer to as radical interchange polymerization (RIP).
	www.sas.upenn.edu /chem/faculty/wayland/wayland.html (393 words)

	Expert: Plastic Failure Analysis and Expert Witness Expert
		He is very knowledgeable in the chain transfer chemistry of both free radical and anionic polymerization of vinyl monomers.
		He is a well-known expert on free radical polymerization as well as on living or controlled radical polymerization.
		He was one of the early pioneers in developing an understanding of living radical polymerization and holds several patents on this area of technology.
	www.intota.com /viewbio.asp?bioID=765810&perID=722299 (1278 words)

	living cationic polymerization
		A novel catalyst is composed of a complex of an organic acid or its ester and a Lewis acid, preferably boron trichloride that can add olefin monomers to increase the molecular weight of the complex from as low as 200 to in excess of a million.
		The complex is active viz., living, until the complex dies, viz., is decomposed or destroyed.
		Initial in-vitro studies indicate that the polymers are much more oxidative and acid stable than silicone rubber and may provide a new generation of improved polymers for implant use in the body.
	www.temarex.com /living.htm (663 words)

	Polymer Synthesis
		Addition polymerization describes the method where monomers are added one by one to an active site on the growing chain.
		In free radical polymerization, the radical attacks one monomer, and the electron migrates to another part of the molecule.
		The degree of polymerization has a dramatic effect on the mechanical properties of a polymer.
	plc.cwru.edu /tutorial/enhanced/files/polymers/synth/synth.htm (1188 words)

	3rd Annual CONTROLLED POLYMER SYNTHESIS - New Approaches in Applications and Processes
		We found that the polymerizations exhibited the diagnostic criteria for a controlled /"living" polymerization: an increase in the molecular weight of the pendant polymer chains with monomer conversion and a narrow molecular weight distribution for the grafted chains.
		Similar to all the living radical polymerization techniques it is of crucial importance to minimize the importance of chain breaking reactions.
		Conventional free-radical polymerisation of (meth)acrylate monomers is critically compared to "living" methodologies, highlighting a number of disadvantages for the latter and exposing the lack of knowledge on polymer properties.
	www.knowledgefoundation.com /events/6211432.htm (3051 words)

	Chem 421 - Anionic Polymerization
		The mechanism of anionic polymerization is a kind of repetitive conjugate addition reaction (the "Michael reaction" in organic chemistry).
		The electron is subsequently transferred to the monomer to create a new radical anion which quickly dimerizes by free radical combination (similar to the termination reaction in free radical polymerization).
		Living polymerization is required for successful synthesis of block copolymers.
	chem.chem.rochester.edu /~chem421/anionic.htm (1176 words)

	Living Polymers: Dead Intresting to Chemists
		So-called "living" polymers are bringing this dream a step nearer, and in the current Hot Ten are two papers on this subject: #5 and #6.
		The system studied was styrene and the polymerization was done on the bulk material, or with this dissolved in diphenyl ether as a solvent.
		The role of the copper catalyst is to transfer atoms, but the essential feature of living polymerization is the maintaining of a steady concentration of the active species and a fast equilibrium between the growing polymers.
	www.sciencewatch.com /may-june98/sw-may-june98_page7.htm (950 words)

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