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Topic: Degree of polymerization

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	Polymer - ninemsn Encarta
		The number of repeating units in one large molecule is called the degree of polymerization.
		Materials with a very high degree of polymerization are called high polymers.
		With a small degree of cross-linking, a loose network is obtained that is essentially two dimensional.
	au.encarta.msn.com /encyclopedia_761564484/Polymer.html (408 words)

	Molecular Weight
		The degree of polymerization (DP) in a polymer molecule is the number, n, of repeating units in the polymer chain.
		At some critical degree of polymerization a polymer will begin to show the mechanical properties, such as strength and toughness, that are characteristic of polymers.
		The value of the critical degree of polymerization that is necessary for a oligomer to show polymer properties is dependent on the intermolecular forces between polymer chains and on the amount of chain entanglement.
	www.lasalle.edu /academ/chem/ms/polymersRus/Resources/MolecWt.htm (1192 words)

	Antithrombogenic biomedical material - Patent 4424311
		The degree of polymerization (n) of polyethylene oxide units in these monomers (A) can be determined by measuring the molecular weight of the compound by gel permeation chromatography or other suitable means.
		In case the degree of polymerization (n) of polyethylene oxide units is lower than 5 and the amount of monomer (A) is smaller than 5% by weight, a medical application of the resulting copolymer will allow easy adhesion of various biological components and its permeability will be inferior.
		The stock solution of polymerization thus prepared was poured in a nitrogen atmosphere between two glass plates spaced from each other through a spacer formed of polyethylene terephthalate with a thickness of 100.mu., then the glass plates were fixed with clamp and polymerization was allowed to take place at 50.degree.
	www.freepatentsonline.com /4424311.html (3472 words)

	Homework2 (Site not responding. Last check: 2007-10-19)
		If the number-average degree of polymerization for polystyrene obtained by the bulk polymerization of styrene at 60°C is 1000, what would be the number-average degree of polymerization if the polymerization were conducted in a 10% solution in toluene (900 g of toluene per 100 g of styrene) under otherwise identical conditions?
		Assume that a polyesterification is conducted in the presence of a strong catalyst (constant concentration of catalyst of 0.01 mol / L throughout the polymerization) and that the monomers are present in stoichiometric ratios.
		(I) Calculate the time required to obtain a number-average degree of polymerization of 50 given that the dicarboxylic acid monomer concentration is 3 mol L-1 and that the polymerization rate constant is 10 L2 mol-2 s-1.
	www.colorado.edu /che/CLASSES/Polymers/Homework2.html (329 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)

	High calorie solutions of low molecular weight glucose polymer mixtures useful for intravenous administration - Patent ...
		The method of providing calories defined in claim 19, wherein said glucose polymers have an average degree of polymerization of at least 4 and are further defined in that at least 85% of the polymers are less than 11 glucose units.
		The average degree of polymerization for the above-described glucose polymer mixture is readily calculable as 3.
		The average degree of polymerization of the glucose polymer mixtures selected for the high calorie solutions of the present invention is from 4 to 10.
	www.freepatentsonline.com /4182756.html (4673 words)

	Seeding Date Alters Carbohydrate Accumulation in Winter Wheat -- Gaudet et al. 41 (3): 728 -- Crop Science
		Degree of polymerization values of fructans in crown tissues of winter wheat cultivars during the autumn, winter, and early spring of 1997-1998 following seeding on 23 August or 20 September at Lethbridge, AB.
		Degree of polymerization values for fructans in crown tissues of winter wheat cultivars during the autumn, winter, and early spring of 1998-1999 following seeding on 8 August, 6 September, or 23 September at Lethbridge, AB.
		The prominent decrease in degree of polymerization of fructan
	crop.scijournals.org /cgi/content/full/41/3/728 (5304 words)

	Evaluation and Comparison of Commercial Mass-Deacidification Processes: Part 1
		(a) Degree of polymerization- analysis measures the average length of the cellulose molecules which are the principal component of paper.
		The degree of thickness or viscosity of sample solutions is determined and can be accurately converted to a number representative of the average length of the molecules that make up the paper sample.
		The differences in degree of polymerization between the printed (central point) and the unprinted (margin) areas of a single page were about 10%, as illustrated by Table 5.
	aic.stanford.edu /sg/bpg/annual/v10/bp10-04.html (5610 words)

	RedOrbit NEWS \| Structural characteristics of new and conventional regenerated cellulosic fibers
		We investigate both the molecular structure (density, degree of polymerization, molecular mass) and the supermolecular structure (crystallinity index, crystallite dimensions, molecular orientation, structure of the voids) of regenerated cellulose fibers, and we determine the influence of their structural parameters on their mechanical properties.
		The molecular mass and degree of polymerization were determined viscosimetrically after dissolving the cellulose samples in the solvent EWNN (FeTNa sodium salt of ferric tartaric acid) according to standard DIN 54 270 [21, 22].
		The degree of polymerization, density, crystallinity index, and molecular orientation factor are higher for lyocell fibers.
	www.redorbit.com /modules/news/tools.php?tool=print&id=16207 (5194 words)

	Polymer Synthesis (Site not responding. Last check: 2007-10-19)
		In free radical polymerization, the radical attacks one monomer, and the electron migrates to another part of the molecule.
		Many important properties of the final result are determined primarily from the distribution of lengths and the degree of polymerization.
		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)

	New Page 1
		Cl is 2 * (12 amu) + 3 * (1 amu) + 35.5 amu = 62.5 amu, the degree of polymerization is 35,000 amu/62.5 amu = 560 mers/molecule.
		In commercial plastics the degree of polymerization normally falls in the range of 75 to 750 mers per molecule.
		Hence it is necessary to calculate the average degree of polymerization if a single index is desired.
	nersp.nerdc.ufl.edu /~soderho/D03.htm (512 words)

	Polymer Technical Info - Dynablend
		The degree of polymerization is the number of monomer units in the chain.
		The molecular weight of a polymer is the degree of polymerization multiplied by the molecular weight of the monomer unit.
		A polymer molecule with a degree of polymerization of 100,000 is made up of 100,000 acrylmide monomer units and will have a molecular weight of 7.1 million (100,000 x 71).
	www.dynablend.com /fdtech.html (1377 words)

	NTT - DEGREE OF POLYMERIZATION (Site not responding. Last check: 2007-10-19)
		The entire details for determining the average viscometric degree of polymerization are given in the ASTM D 4243 method and are only briefly mentioned here.
		The average viscometric degree of polymerization represents the average number of glucose units in the cellulose polymer and these values can range from 800 to 1600 units with the most probable value being about 1200.
		As shorter length chains are formed this lowers the average degree of polymerization.
	www.nttworldwide.com /dp.htm (493 words)

	POLYNUCLEOTIDE COMPOSITIONS (WO9615778A1)
		More preferably, the degree of polymerization shall be between about 5 and about 180, still more preferably, between about 5 and about 60.
		The degree of polymerization of the polycationic polymer can preferably be between about 10 and about 10, 000.
		More preferably, the degree of polymerization shall be between about 10 and about 1,000, still more preferably, between about 10 and about 100.
	www.delphion.com /details?pn=WO09615778A1 (442 words)

	Hydrolytic Pretreatment of Softwood and Almond Shells. Degree of Polymerization and Enzymatic Digestibility of the ...
		The average degree of polymerization of the cellulose retained in the pretreated substrate, DP v
		Glucose yields after enzymatic saccharification of the pretreated substrates turned out to be higher for almond shells than for the softwood mixture, which had a very low susceptibility to enzymatic hydrolysis throughout the spectrum of experimental conditions investigated.
		The different behavior between these lignocellulosic species is not caused by different degrees of cellulose depolymerization nor by the removal of different amounts of carbohydrates during pretreatments in equivalent conditions.
	pubs.acs.org /cgi-bin/abstract.cgi/iecred/1997/36/i03/abs/ie960048e.html (303 words)

	Polyvinyl Alcohol (01/02S5) (Site not responding. Last check: 2007-10-19)
		In terms of degree of hydrolysis, the principal grades of polyvinyl alcohol produced can be classified as fully hydrolyzed (97.5-99.5 percent degree of hydrolysis) and partially hydrolyzed (87-89 percent degree of hydrolysis).
		In general, fully hydrolyzed grades of polyvinyl alcohol are used mainly in paper coating, in textile warp sizing of hydrophilic fibers, such as cotton and rayon staple yarns, and in laminating film in safety glass (after conversion to polyvinyl butyral).
		Its solubility in water depends on its degree of polymerization and degree of hydrolysis, with the latter factor being especially significant.
	www.chemsystems.com /newsletters/perp/Dec02_N01S5.cfm (937 words)

	Molar mass distribution - Wikipedia, the free encyclopedia
		The Molar mass distribution in a polymer describes the relationship between a polymer fraction and the molar mass of that polymer fraction.
		In linear polymers the individual polymer chains rarely have the exact same degree of polymerization and there is always a distribution around an average value.
		The molar mass distribution of a polymer sample depends on factors such as chemical kinetics and work-up procedure.
	en.wikipedia.org /wiki/Molar_mass_distribution (519 words)

	Unit 7: Synthetic Fibers
		Polymerization is the process of joining molecules (small building blocks of matter) together.
		The length of the chain is called the degree of polymerization.
		At the command of the dancing tutor the couples partially separate from each other, i.e., they only hold each other with one hand, while each partner takes with his or her free hand that of a partner from a second couple.
	invention.smithsonian.org /centerpieces/whole_cloth/u7sf/u7materials/sfPac5.html (1572 words)

	[No title]
		Prepared “polymer chains”, which consisted of various lengths of plastic pearl necklace, were counted and weighed to determine the degree of polymerization for the number average, weight average, and molecular weight averages.
		The degree of polymerization was calculated by dividing the molecular weight averages, found in Table 2, by the weight of one repeat unit, 0.2620g.
		The degrees of polymerization for each average are vastly different compared to one another.
	filebox.vt.edu /p/pgaudrea/ExperimentB.doc (526 words)

	Student Project Details \| UCF College of Optics & Photonics: CREOL & FPCE (Site not responding. Last check: 2007-10-19)
		Abstract:Methods were developed for measuring the degree of polymerization and optical properties of resins that can be photo-cured under one- or multi-photon-initiated polymerization and are specifically formulated for preparation of optical waveguides by multi-photon three-dimensional microfabrication.
		Plans are outlined for extending this work to include Raman spectroscopy of progressively cured films so that the degree of polymerization can be measured and correlated with optical properties n and κ.
		Raman spectroscopy can then be similarly applied for measuring the degree of polymerization, and thus n and κ, of microstructures fabricating using multi-photon polymerization.
	www.creol.ucf.edu /Research/REU/StudentProjectDetail.asp?PeopleID=5763&Yr=2005 (191 words)

	Cationic Polymerization
		The cationic polymerization of styrene, initiated by SnCl4/H2O is used to illustrate the effect of temperature on reaction rate and molecular weight and also the effect of Friedel-Crafts alkylation reactions on the molecular weight.
		This relationship of the energies of activation is encountered in many cases, since in initiation and propagation a dipolar species approaches a neutral molecule, a low energy process, while for termination an ion a pair is required to break apart and rearrange, a high energy process.
		Large increase in the rate and degree of polymerization are generally observed as the solvating power of the reaction medium increases.
	www.pslc.ws /macrog/lab/cation.htm (1343 words)

	Anionic Polymerization of Styrene
		The butyl lithium induced anionic polymerization of styrene is used to produce a "living" polymer.
		The "living nature" of the polymerization is demonstrated, and the influence of monomer and initiator concentration of the degree of polymerization is investigated.
		The coupling and disproportionation terminations for free radical polymerizations are not possible with anionic polymerizations due to coulombic repulsion of two negatively charged species.
	www.pslc.ws /macrog/lab/anion.htm (1000 words)

	Quantitative Fractionation of Grape Proanthocyanidins According to Their Degree of Polymerization
		A method was developed for the fractionation of grape (seed or skin) proanthocyanidins according to their degree of polymerization.
		Mean degree of polymerization of separated proanthocyanidins ranged increasingly from 4.7 to 17.4 in seed (8.1 for total extract) and from 9.3 to 73.8 in skin (34.9 for total extract).
		The method proposed is very interesting for the study of grape proanthocyanidins according to their degree of polymerization because it gives both qualitative and quantitative information especially on the highly polymerized forms, which were not fractionated by previous techniques.
	pubs.acs.org /cgi-bin/abstract.cgi/jafcau/1999/47/i07/abs/jf990029q.html (249 words)

	TAML: Polymer Synthesis
		Through these investigations on materials synthesized by highly specialized high vacuum anionic polymerization techniques, they have discovered how molecular architecture, composition, and blending can be used to systematically manipulate the morphology and extent of long-range nanostructural order present in these materials.
		The increase in both rate and degree of polymerization can be attributed, at least partially, to diminished rate of termination in these dispersion polymerizations.
		The group is interested in the synthesis of novel, well-defined polymer brushes, their behavior in response to environmental changes, and their applications in the emerging fields such as nanotechnology.
	www.phys.utk.edu /taml/fields/synthesis.html (1520 words)

	Sierra Analytics-Software for Mass Spectrometry and Chemistry (Site not responding. Last check: 2007-10-19)
		One category includes several forms of molecular weight averages and degree of polymerization values, and the other relates to the characterization and quantification of individual chemical components, or chemical component series, that may be present.
		The molecular weight averages and degree of polymerization formulae are shown below.
		They are calculated from M, the mass in Daltons (Da), N, the number of moles, and R is the mass of the polymer repeat unit.
	www.massspec.com /PolymerixDetails.html (542 words)

	Living Graph (Site not responding. Last check: 2007-10-19)
		In stepwise polymerization any two monomers present in the reaction mixture can link together at any time and growth of the polymer is not confined to chains that are already forming.
		We measure the progress of polymerization in terms of the concentration of the -COOH groups in the sample (which we denote A), for these groups gradually disappear as the condensation proceeds.
		We see that the average length grows linearly with time, so the longer a stepwise polymerization proceeds, the higher the average molar mass of the product.
	www.oup.com /uk/orc/bin/0198792859/resources/livinggraphs/graphs/P726C11.html (246 words)

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