Molecular weight Polystyrene

Description Particle size (/tm) Minimum theoreticai piates/30 cm Exclusion limit (polystyrene molecular weight) Standard flow rate (ml/min) Maximum flow rate (ml/min) Maximum pressure drop/30 cm (bar)... 

Berlin and coworkers (5,56) desired to obtain a material with an increased mechanical strength. They carried out a plasticization of bulk ami emulsion polystyrene molecular weight 80000 and 200000 respectively at 150-160° C, with polyisobutylene, butyl rubber, polychloroprene, polybutadiene, styrene rubber (SKS-30) and nitrile rubber (SKN 18 and SKN 40). The best results were obtained with the blends polystyrene-styrene rubber and polystyrene-nitrile rubber. An increase of rubber content above 20-25% was not useful, as the strength properties were lowered. An increase in the content of the polar comonomer, acrylonitrile, prevents the reaction with polystyrene and decreases the probability of macroradical combination. This feature lowers the strength, see Fig. 14. It was also observed that certain dyes acts as macroradical acceptors, due to the mobile atoms of hydrogen of halogens in the dye, AX ... 

POLYSTYRENE MOLECULAR WEIGHT 26,000 g/MOLE POLYISOPRENE MOLECULAR WEIGHT 94,000 g/MOLE... 

Fig. 5.8. Cotangent of the doubled extinction angle (corrected for solvent birefringence) vs. reduced shear rate f s for a series of cellulose tricarbanilate fractions in benzophenone at 55° C (772). Broken and dotted lines are explained in the text. Hatched area indicates location of experimental results on anionic polystyrenes. Molecular weights of cellulose tricarbanilate fractions () 27000, (f) 38000, (A) 57000, (a) 90000, (o) 152,000, ( ) 280,000, (o) 500,000, ( ) 720,000 and...

Figure 4. Critical concentrations, g25, of phase separation for block copoly-mers and polymer mixtures in benzene solutions at 25°C as functions of the polystyrene molecular weight...

The effect of molecular weight is affirmed by the results for TR-41-2443 (Figure 5). This copolymer is similar to TR-41-2445 except that the polystyrene molecular weight is about 2.5 greater than that of TR-41-2445. The Tg in this case is 93.5°C, and since it was prepared in the... 

Gel-Permeation Chromatography. A Water Associates HPLC with four Shodex GPC-AD-802S columns was used with dimethylformamide at a flow rate of 1 mL/minute. The gel is polystyrene-divinyl benzene copolymer and has exclusion limit of 8,000 by polystyrene molecular weight. Sample injection... 

Table 21.1 Effect of polystyrene molecular weight on the tensile strength of S-l-S. Reproduced with permission from Legge, Holden and Schroeder, Thermoplastic Elastomers A Comprehensive Review, Hanser Verlag, Munich, 1987...

For GPC analysis, a high-speed liquid chromatograph (Toyo Soda Company, model HLC-801 A) was used. The columns (G 2000 H and G 4000 H, two by two) were connected in series. The detector was a differential refractometer. The sample was dissolved in THF (65 mg of PCS per 3 mL of THF) and analyzed at a current speed of 1 mL/min and a pressure of 8 kg/cm. The average molecular weight was calculated on the basis of the elution of polystyrene molecular weight standards. 

Problem 2.11 Assuming that the RMS end-to-end distance is an approximation to the diameter of the spherical, coiled polymer in dilute solution, calculate the volume occupied by one molecule of polystyrene (molecular weight 10 ) in a theta solvent at 25°C. (carbon-carbon bond length = 1.54x10 cm tetrahedral bond angle 109.5°)... 

At high temperatures, [Ru(CH3)(Tp)(CO)(NCMe)] acts as catalyst for the production of polystyrene. The dependence of polystyrene molecular weight on benzene/cumene molar ratios suggests a radical polymerization mechanism. The polymerization of methyl methacrylate, in the presence of [Ru(CH3)(Tp)(CO)(NCMe)j with carbon tetrachloride or methyl dichloroacetate, has been observed at 90°C.31... 

Figure 6.9 Neutron scattering data from a binary mixture, annealed at 160°C, of a hydrogenous polystyrene (molecular weight 870,000) and a deuterated polystyrene (molecular weight 1,150,000). The solid curve is a fitted theoretical curve with x equal to 1.9 x 10-4, and the upper broken curve is for x =0 expected in the absence of the deuterium isotope effect. (From Bates and Wignall.19)...

Fig. 13.12. The distance dependence of the force of interaction between crossed mica plates coated by polystyrene in cyclohexane at 24 °C polystyrene molecular weight l,6x 10 2,1 x 10 (after Klein, 1982).

Little work has been published on depletion stabilization in nonaqueous dispersion media. Clarke and Vincent (1981a) have noted that it is possible to prevent silica particles stabilized by polystyrene in ethylbenzene from undergoing depletion flocculation by adding a high concentration of polystyrene (v2 =0 015 for a free polystyrene molecular weight ofca 2 x 10 ). This was the first reported observation of depletion stabilization in nonaqueous dispersion media. 

Ellison CJ, Mundra MK, Torkelson JM (2005) Impacts of polystyrene molecular weight and modification to the repeat unit structure on the glass transition-nanoconfinement effect and the cooperativity length scale. Macromolecules 38 1767-1778... 

Fig. 35. MEK volume fraction, Oi, as a fimction of normalized position, The polystyrene molecular weight was M = 52 000. The position, = 0 is the center of the slab. The time increment starting from the first curve on the right is At = 1000 s...

Fig. 37. The rubbery-solvent interface (S), the glassy-rubbery interface (R), and the gel layer thickness (S-R) as a function of dissolution time. The polystyrene molecular weight was M = 52 000...

TOI Toil, K. and Paul, D.R., Effect of polystyrene molecular weight on the carbon dioxide sorption isotherm, Macromolecules, 15, 1104, 1982. 

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