Molecular weight distribution of polystyrene

ASTM D-5296-92, Standard Test Method for Molecular Weight Averages and Molecular Weight Distribution of Polystyrene by High Performance Size-Exclusion Chromatography. ASTM Annual Book of ASTM Standards, Vol.08.03, pp. 425-438. 

Figure 1 Property distribution in a linear homopolymer molecular weight distribution of polystyrene (styrene units represented by "A")-...

Figure 12. Molecular weight distribution of polystyrene prepared anionically in THP...

In the Introduction it has been mentioned that the immediate reason for the development of phase distribution chromatography was the search for a fast and exact method to determine very narrow molecular weight distributions of polystyrenes obtained from anionic polymerization. The long way to reach this goal became evident only in the course of the investigations shown in the previous sections and representing a basis for the computation of such MWDs. In fact, not only exact measurements are necessary, but also mathematical expressions for the measured calibration curves and for the spreading of the injected concentration profile in the column must be stated, which cannot be done empirically. 

McCormick Molecular weight distribution of polystyrene by sedimentation velocity analysis. J. Polymer Sci. 36, 341 (1959). 

S.W. Provencher, J. Hendrix, L. DeMayer and N. Paulussen, Direct determination of molecular-weight distributions of polystyrene in cyclohexane with photon correlation spectroscopy, J. Chem. Phys. 69 (1978) 4273-4276. 

FIG. 16.16 Shear rate dependence of viscosity as a function of concentration. Data were obtained on a single narrow molecular weight distribution of polystyrene (Mw = 411 kg/mol) in n-butyl benzene at 30 °C. From Graessley, Hazleton and Lindeman (1967). Courtesy Society of Rheology. 

Molecular Weight and Molecular Weight Distribution of Polystyrene Obtained with Suspension Polymerization... 

An important objective of this research was to determine directly the molecular weights and the molecular weight distribution of polystyrene branches in poly(buta-diene-g-styrene). 

Lattimer, R. R, Harmon, D.., and Hansen, G. E., Determination of molecular weight distributions of polystyrene oligomers by field desorption mass spectrometry, Anal. Chem., 52, 1808, 1980. 

The model for the batch suspension polymerization reactor was developed using in the gPROMS simulator. A windows based interface developed in Delphi programming language was employed to build, modify and run the reactor model. The model can predict the monomer conversion, initiator(s) and blow agent (pentane) concentrations, polymerization rate, molecular weight distribution of polystyrene, external jacket inlet/outlet temperatures, and the reactor temperature and pressure. 

Figure 3.21 The molecular weight distribution of polystyrene PS 50000 with stationary phase Phenogel M, mobile phase, butanone.

In this case, it is useful to use the whole molecular weight distribution (see [60]) or a higher number of pseudocomponents for the modeling. As an example. Fig. 18 shows the molecular weight distributions of polystyrene in the two coexisting phases observed with cyclohexane/carbOTi dioxide solvent mixture [63]. An initially bimodal mixture of two polystyrene samples (40 kg/mol and 160 kg/mol) was mixed with cyclohexane and carbon dioxide at 170°C and different pressures to generate two hquid phases. 

Fig. 18 Molecular weight distributions of polystyrene (mixture of two almost monodisperse samples of 40 kg/mol and 160 kg/mol) in the coexisting phases of a polystyrene/cyclohexane/ carbon dioxide mixture at 170°C and varying pressures [63]. The two left-hand columns give the GPC analysis of the polymer-lean and polymer-rich phases. The two right-hand columns show the molecular weight distributions as calculated using the SAFT model using 30 pseudocomponents [64]...

Flow field - flow fractionation has been used" to fractionate polystyrene and Kirkland and Rementer" used thermal field flow fractionation using Mark Houweq constants to determine the molecular weight distribution of polystyrene and poly methylstyrene. 

Desorption chemical ionization mass spectrometry has been used to determine the molecular weight distribution of polystyrene.. The liquid chromatographic behaviour has been studied of polystyrene homopolymers on a C4 pore diameter reversed phase column. Separation was achieved on a molecular weight basis using a tetrahydrofuran-... 

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