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Topic: Weight average molecular weight

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	Number Avearage and Weight Average Molecular Weight
		Using strings of varying lengths to represent polymers of varying degrees of polymerization, students are able to calculate the number average molecular weight, the weight average molecular weight and the polydispersity index for a "sample" with a distribution of chain lengths.
		The number average molecular weight is the total weight (the sum of column 4) divided by the total number of "molecules" (the sum of column 2).
		The weight average molecular weight is the sum of column 5 divided by the sum of column 4.
	www.pslc.ws /macrog/activity/mwstrin.htm (273 words)

	Number average molecular weight - Wikipedia, the free encyclopedia
		The number average molecular weight is the common average of the molecular weights of the individual polymers.
		It is determined by measuring the molecular weight of n polymer molecules, summing the weights, and dividing by n.
		An alternative measure of the molecular weight of a polymer is the weight average molecular weight.
	en.wikipedia.org /wiki/Number_average_molecular_weight (165 words)

	New Page 1
		Consequently, molecular weight determinations are usually made indirectly by such physical means as measurement of viscosity, osmotic pressure, or light scattering, all of which are affected by the number, size, or shape of molecules in a suspension or in a solution.
		The "weight-average" molecular weight is particularly significant in the analysis of properties such as viscosity, where the weight of the molecules is important.
		Weight- average molecular weight and molecular weight distributions are determined from ultracentrifuge sedimentation, diffusion and light scattering.
	nersp.nerdc.ufl.edu /~soderho/D03.htm (512 words)

	molecular weight. The Columbia Encyclopedia, Sixth Edition. 2001-05
		The molecular weight may be calculated from the molecular formula of the substance; it is the sum of the atomic weights of the atoms making up the molecule.
		Molecular weights of substances may be determined experimentally in various ways, the method employed usually depending on the state (solid, liquid, or gas) of the substance.
		The molecular weights of substances that are not normally gaseous and do not evaporate without decomposition are sometimes determined from their effects on the melting point, boiling point, vapor pressure, or osmotic pressure of some solvent (see colligative properties).
	www.bartleby.com /65/mo/molecwght.html (519 words)

	Average - Wikipedia, the free encyclopedia
		This "average" (arithmetic mean) income is higher than most people's incomes, because high income outliers skew the result higher (in contrast, the median income "resists" such skew).
		The geometric mean, harmonic mean, generalized mean, weighted mean, truncated mean, and interquartile mean are described in their own articles and in the Mean article.
		Average is derived from Romance avaria, a 'tax'; this is in turn connected with the Arabic or Turkish avaria or avania of the same meaning.
	en.wikipedia.org /wiki/Average (570 words)

	Technical Program Paper Detail - AIChE
		The density and the weight-average molecular weight(Mw) of the reaction mixture are measured on-line to estimate the states of the semibatch copolymerization reactor by using the conventional extended Kalman filter.
		The density is calculated from the molecular weights and fractions of monomer 1, monomer 2, solvent and copolymer in the reactor.
		Accordingly, the mole fraction f1 of MMA in the remaining monomers and the weight average molecular weight(Mw) are chosen as the controlled outputs while the feed flow rate of MMA and the reaction temperature are taken as the control inputs.
	www.aiche.org /conferences/techprogram/paperdetail.asp?PaperID=1005&DSN=annual01 (1013 words)

	Electrophotographic photoreceptor comprising binder resin containing acidic groups - Patent 4954407
		If the weight average molecular weight of resin (B) containing neither the acidic group-containing component nor the curing functional group-containing components less than 8.times.10.sup.4, the effect of improving film strength becomes insufficient, and the printing durability of an offset master plate produced is insufficient form obtaining more than 10000 prints.
		The proportion of the polymerization or copolymerization component corresponding to repeating unit (a-i) in resin (A) is from 30 to 100% by weight, preferably from 60 to 100% by weight.
		In general, the weight ratio of resin (A) to resin (B) is 5 to 80:95 to 20, preferably 10 to 60:90 to 40.
	www.freepatentsonline.com /4954407.html (7418 words)

	Facts and Fallacies about Colloidal Silver
		The weight ratio of coagulant aid to bridging flocculant, on the other hand, is preferably in the range from about 10:1 to about 1:6, preferably from about 5:1 to about 1:3, more preferably from about 3:1 to about 1:1.
		[0043] Preferably, the weight ratio of water-purification composition to disinfectant when used separately is from 10000:1, or preferably from 5000:1 or preferably from 1000:1, or preferably from 500:1, and preferably to 2:1, or preferably to 10:1, or preferably to 25:1, or preferably to 50:1, or preferably to 100:1.
		[0120] Preferably, the weight average molecular weight of the second polymeric material is at least 2500000, or preferably at least 3000000, or preferably at least 5000000, or preferably at least 7500000, or preferably at least 10000000, or preferably at least 15000000.
	www.csfacts.com /pages/pwater2.html (10117 words)

	Number Average and Weight Average Molecular Weight for Macrogalleria
		The number average molecular weight is the total weight of the sample divided by the number of molecules in the sample.
		For weight fraction of one type of molecule, it is the weight of that type of molecule divided by the total weight of the sample.
		The distribution of molecular weights in a polymer sample is often described by the ratio of the weight average molecular weight to the number average molecular weight.
	www.pslc.ws /macrog/activity/average.htm (516 words)

	Molecular Weight (Site not responding. Last check: 2007-11-04)
		Molecular weight is defined as the average molecular weight of the gases in the atmosphere.
		The molecular weights for pure gases were obtained or calculated from web elements periodic table of the elements.
		Molecular weight is used with temperature and pressure to calculate column height and density of the atmosphere.
	members.axion.net /~enrique/molecularweight.html (154 words)

	weight-average molecular weight — Infoplease.com
		molecular weight - molecular weight molecular weight, weight of a molecule of a substance expressed in atomic mass...
		Theoretical influence of polyester molecular weight distribution variation on melt viscosity during injection molding and extrusion......
		Molecular Weight and Rheology: A Sketch of a Resin.
	www.infoplease.com /id/A0920252 (199 words)

	Hypnosis Weight -- Recommendations and Resources (Site not responding. Last check: 2007-11-04)
		For the weight average molecular weight, this is calculated by
		As written on Sep 30, 2004: "Intuitively, if the weight average molecular weight is w, and you pick a random monomer, then the polymer it belongs to will have a weight of w on average."
		While highway hypnosis may be a common occurrence, common sense suggests that when driving the full weight of consciousness is brought to bear on the task at hand.
	www.becomingapediatrician.com /health/77/hypnosis-weight.html (844 words)

	Molecular Weight Determinations - Polyhedron Laboratories, Inc.
		ASTM D5296-05 Standard Test Method for Molecular Weight Averages and Molecular Weight Distribution of Polystyrene by High Performance Size-Exclusion Chromatography - This test procedure deals with the determination of molecular weight averages and the distribution of molecular weights for linear, soluble polymers by liquid high-performance size-exclusion chromatography (HPSEC).
		This test procedure is valid for specimens containing molecular weight components that have elution volumes falling within the range defined by polystyrene standards.
		ASTM D4001-93 Standard Test Method for Determination of Weight-Average Molecular Weight of Polymers By Light Scattering - This test procedure explains the test methods for determining the weight-average molecular weight of polymers by light scattering.
	www.polyhedronlab.com /mole.html (388 words)

	The Thomas Group - PTCL, Oxford
		) the overall intensity is proportional to the molecular weight of the polymer.
		The scattering may be regarded as the average of the sum of the scattering from all pairs of segments in the polymer.
		When the light scattering is affected by the dimensions of the polymer and is also being used to determine the molecular weight it is necessary to extrapolate the scattering to zero scattering angle to obtain the correct molecular weight.
	physchem.ox.ac.uk /~rkt/lectures/liqsolns/scattering.html (775 words)

	New Page 1
		Determine the "number-average" molecular weight for the polymer of Example 1.
		As seen from the above example, the number-average molecular weight is 16,010, while the weight-average molecular, determined before, was 19,200.
		Whenever there is a distribution in sizes, the "number-average" molecular weight will be less than the "weight-average" molecular weight, because of the large numbers of small molecules in the smaller weight fractions.
	nersp.nerdc.ufl.edu /~soderho/d03b.htm (135 words)

	World Intellectual Property Organization (Site not responding. Last check: 2007-11-04)
		Where the xylene soluble portion clearly has both a high molecular weight component and a low molecular weight component, we have found that the low molecular weight component is attributable to amorphous, low molecular weight propylene homopolymer.
		These molecular weight distributions should be obtained in the absence of visbreaking or peroxide or other post reactor treatment designed to reduce molecular weight.
		From the weight of each fraction and its ethylene content, a plot is prepared of weight percent composition vs. cumulative weight percent of polymer, and a smooth curve is drawn through the points.
	www.wipo.int /ipdl/IPDL-CIMAGES/view/pct/getbykey5?KEY=01/58970.010816&ELEMENT_SET=DECL (7632 words)

	Determination of Molecular Masses of Proteins in Solution
		The average error between the observed and predicted MW ranged from 0.8% to 16.3%, with an overall median average error of 2.3% for the 14 proteins examined.
		Nevertheless, the average MWs calculated by ASTRA (from a Debye analysis carried out on the entire peak) were 78 kd for transferrin and 41 kd for ovalbumin, which are both within 5% of the expected values of 75.2 and 42.8 kd, respectively.
		The scattering of molecular weights at the edges of the peaks results from a low signal to noise ratio in the refractive index and light scattering signals, which propagates into low precision for the molecular weight determination.
	www.abrf.org /JBT/1999/June99/jun99folta.html (6505 words)

	[No title] (Site not responding. Last check: 2007-11-04)
		If the average size of the polymer is large compared to the size of a monomer, the molecular weight distribution may be considered a continuous function of m, W(m).
		That is, the fraction of polymer molecules with molecular weights between m and m + dm is W(m)dm.
		Gel permeation chromatography was used to experimentally determine the molecular weight distribution of a polymer sample.
	www.engr.usask.ca /classes/CHE/477/assignments/ProblemLab5.doc (584 words)

	BSARep
		In the case of a monodisperse peak, the average molar mass will be independent of the averaging method used and polydispersity will equal to 1.
		The average molecular weight was estimated as 215 kDa for peak #1, 137 kDa for peak #2 and 65.6 kDA for peak #3.
		Mz is the molecular weight (MW); this might for instance be measured during sedimentation analysis.
	info.med.yale.edu /wmkeck/biophysics/Bsarepa.htm (2059 words)

	Patent 6,232,301 (Site not responding. Last check: 2007-11-04)
		That is, the larger the bladder dry weight or the smaller the intravesical amount of hydroxyproline of the aforementioned rabbit vesical mucosa trouble model after the bladder of the model is applied with a solution of various agents, the stronger the ability of preventing fibrillation of vesical proper muscle coat of the solution.
		Because the concentration of hyaluronic acid and/or a salt thereof in the solution is relatively low (e.g., 0.1-0.8% by weight, preferably 0.2-0.6% by weight), the hyaluronic acid and the like may be degraded into lower molecular weight compounds when they are subjected to heat sterilization or stored for a long term.
		In such a case, it is necessary to use a means for preventing the degradation of hyaluronic acid and the like into lower molecular weight compounds, which may be a known one.
	www.pharmcast.com /Patents/Yr2001/May2001/051501/6232301_Bladder051501.htm (2234 words)

	Determination of Molecular Weight
		These new parameters are assumed to have the same molecular weight dependence as the end-to-end distance and radius of gyration for the coils.
		For instance, a low molecular weight oligomer will easily be force into the pores of the gel and will take a circuitous path through the column, traveling a distance equivalent to hundreds of the column length.
		The selectivity of this process for molecular weight is outstanding and the range of molecular weights which can potentially be characterized by this technique is only limited by the ability to produce controlled spaced gels.
	www.eng.uc.edu /~gbeaucag/Classes/Characterization/MolecularWeighthtml/MolecularWeight.html (2323 words)

	Weight Percentage (Site not responding. Last check: 2007-11-04)
		In baseball statistics, on base percentage (OBP) (sometimes referred to as on base average (OBA)) is a measure of how often a batter gets to first base for any reason other than a fielding error or a fielder's choice.
		In baseball statistics, fielding percentage, also known as fielding average, is a measure that reflects the percentage of times a defensive player handles a batted ball properly.
		It is calculated by the sum of putouts and assists divided by the number of total chances.
	www.wwwtln.com /finance/202/weight-percentage.html (632 words)

	weight-average molecular weight on Encyclopedia.com (Site not responding. Last check: 2007-11-04)
		Theoretical influence of polyester molecular weight distribution variation on melt viscosity during injection molding and extrusion as influenced by ester-ester interchange.
		Modeling of Molecular Weights in Industrial Autoclave Reactors For High Pressure Polymerization of Ethylene and Ethylene-Vinyl Acetate.
		Spinning and drawing properties of ultrahigh-molecular-weight polyethylene fibers prepared at varying concentrations and temperatures.
	www.encyclopedia.com /html/x/x-weightav.asp (294 words)

	Weight Average Molecular Weight, Mw (Site not responding. Last check: 2007-11-04)
		Weight Average Molecular Weight, Mw Slide 12 of 33
		Weight Average Molecular Weight, Mw Weight Average Molecular Weight, Mw
		Useful for understanding polymer properties that relate to the weight of the polymer, e.g., penetration through a membrane or light scattering.
	www.csuchico.edu /~jpgreene/itec041/m41_ch03/sld012.htm (53 words)

	Energy Citations Database (ECD) - Energy and Energy-Related Bibliographic Citations
		Accurate molecular weight distributions are essential to the determination of the molecular structures of asphalt.
		Due to molecular complexity and interaction among the molecules of asphalt, precise measurement for the molecular weights of asphalt can not be achieved.
		Among these Corbett fractions, naphthalene aromatics have the lowest number average molecular weight; saturates have the lowest weight average molecular weight and dispersity; and asphaltenes have the highest number and weight average molecular weights and dispersity.
	www.osti.gov /energycitations/product.biblio.jsp?osti_id=380191 (223 words)

	Sierra Analytics-Software for Mass Spectrometry and Chemistry (Site not responding. Last check: 2007-11-04)
		Molecular ion mass spectra of hydrocarbons or other materials containing multiple homologous series distributions can be deconvolved to yield information on the distribution among unsaturation states, degree of chemical modification, etc.
		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.
	www.massspec.com /PolyDetails.html (593 words)

	World Intellectual Property Organization (Site not responding. Last check: 2007-11-04)
		The lower limit of the weight-average molecular weight of the first crystalline polymer is 50,000, preferably 100,000.
		The upper limit of the weight-average molecular weight of the first crystalline polymer is generally 10,000,000, e.
		by volume of a first crystalline polymer having a weight-average molecular weight of at least 50,000, and (ii) at most 50% by volume of a second crystalline polymer having a weight-average molecular weight of at most 10,000, and (2) a particulate electrically conductive filler dispersed in the polymer mixture.
	www.wipo.int /ipdl/IPDL-CIMAGES/view/pct/getbykey5?KEY=01/09905.010208&ELEMENT_SET=DECL (3936 words)

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