Polystyrene dissolved

Sf lf-Test 8.15A The osmotic pressure of 3.0 g of polystyrene dissolved in enough benzene to produce 150. mL of solution was 1.21 kPa at 25°C. Calculate the average molar mass of the sample of polystyrene. 

Hollow and porous polymer capsules of micrometer size have been fabricated by using emulsion polymerization or through interfacial polymerization strategies [79,83-84, 88-90], Micron-size, hollow cross-linked polymer capsules were prepared by suspension polymerization of emulsion droplets with polystyrene dissolved in an aqueous solution of poly(vinyl alcohol) [88], while latex capsules with a multihollow structure were processed by seeded emulsion polymerization [89], Ceramic hollow capsules have also been prepared by emulsion/phase-separation procedures [14,91-96] For example, hollow silica capsules with diameters of 1-100 micrometers were obtained by interfacial reactions conducted in oil/water emulsions [91],... 

Repeat the activity using warm water instead of acetone. When water is used, the starch peanut dissolves and the polystyrene peanut does not. The acetone and polystyrene do not exhibit hydrogen bonding, while starch peanuts and water do exhibit hydrogen bonding. This illustrates the general principle of like dissolves like. Not all the polystyrene dissolves because of the presence of cross-linked units that form the polystyrene. 

Kockelbekgh and Smets 132) have used chloromethylated polystyrene dissolved in carbon disulfide in the presence of aluminium... 

Napalm B was developed by Dow Chemical during the Vietnam War as a replacement for the original napalm jelly in firebombs. It is stickier and burns much hotter than the original filler. The Dow formula used 25 percent gasoline, 25 percent benzine, and 50 percent polystyrene. Polystyrene is a common plastic used for such diverse items as toys, styrofoam cups, and packing-filler "peanuts." As anyone who has tried to spray-paint a styrofoam cooler knows, polystyrene dissolves into a sticky mush when it comes in contact with hydrocarbons such as paint or gasoline. It is this quality of polystyrene that makes napalm B so effective for molotov cocktails. 

Figure 5. Log M [77] vs. the fractional elution volume Ve/VT for anionic polystyrenes dissolved in toluene,...

SYNTHESIS OF POLYfP-IODOSTYRENE1. Poly(p-iodostyrene) or iodinated polystyrene (IPS) samples were prepared by iodination of polystyrene using the procedure described by Braun (6). Polystyrene dissolved in... 

Illers and Jenckel [36] studied aPS plasticized with diethyl, dibutyl and dioctyl phthalate. The mechanical measurements of tan<5 at 1 Hz showed the a relaxation moving rapidly to lower temperatures with increasing plasticizer content. The (3 relaxation was submerged below the a relaxation in the plasticized systems. A relaxation process was reported with a peak temperature ranging from 180 up to 267 K on addition of diethyl, dibutyl and dioctyl phthalate, respectively. The authors called this relaxation process y but they were inclined to ascribe it to the motion of low molecular weight polystyrene dissolved in discrete droplets of plasticizer. According to Heijboer [4], this can also be a motion within the plasticizer molecule, e.g. of the n-butyl group in dibutyl phthalate. 

The precipitation behavior of the polymer is intapreted by a photostimulated change of the critical miscibility temperature T. For polystyrene dissolved in cyclohexane, the polymer precipitates at temperature below T. According Fox and Flory [65], T depends on the molecular weight M as... 

The first part of the log function up to the maximum may be interpreted as follows. At the beginning, the reaction proceeds according to the conception of Harkins. Dispersed PMMA takes up 3 to 4 times its monomer (by weight) contrary to PMMA, dispersed polystyrene dissolves only 1 to 1.5 times its own weight of monomer (Table I). In the case of the emulsion polymerization of MM A, the pure monomer phase therefore disappears at about 30% conversion. From here on, the Trommsdorff (38) or gel effect acts to increase the over-all reaction rate until the maximum is reached. During this period, the bulk of the monomer in monomer-polymer particles is consumed. 

Depex-Polystyrene dissolved in xylene (DPX) mountant for microscopy (with xylene) (BDH). 

The values of Aj obtained from static low-angle light scattering are presented In Table II. The second vlrlal coefficient has previously been measured (10) for unmodified polystyrene dissolved In THF and Is In reasonable agreement with the values determined In this study. In addition, calculation of K cp/Rg requires the measurement of the specific refractive Index Increment, dn/dc. This... 

Conway de Macario et al. (1990) adapted the slide immunoenzy-matic assay (SIA) for DNA hybridization. This may be of interest for laboratories using the modular SIA system or instrumentation. Slides with sample circles are coated with polylysine or polystyrene, dissolved in toluene, to anchor the DNA. 

In the experiments which will be mentioned, the polymer is generally atactic polystyrene we shall also discuss experiments done with polymethylstyrene and polydimethylsiloxane. Polystyrene dissolves easily at room temperature. The good solvents which are used in this case, are... 

The following data were obtained for polystyrene dissolved in cyclohexane, when viscosity measurements were made at the 0 temperature of 308 K (solvent flow time, = 100 s). 

Fig. The fraction of polystyrene dissolved as a function of time. The polymer molecular weight was M = 52000...

Fig. 20. Influence of shear rate initial rate of degradation (dB/dtX=o vs. shear rate for polystyrene dissolved in-trons-decalin AT denotes the distance to the demixing temperature...

The phase diagrams expressed in temperature versus volume fraction V2 are shown in Fig. 7.8 for a series of different molar masses of polystyrene dissolved in diisobutyl ketone (the lower curves correspond to lower molar masses). Lower molar masses dissolve at lower temperature and yield a narrower two-phase area. To find the upper critical temperature of phase separation, the UCST, one can insert for low polymer concentrations V2 the first few terms of the series-expansion for In Vj = hi (1 - Vj) given in Fig. 7.8 into the expression for 8AG ,i/dni (given in Fig. 7.7). With the first two terms of the expansion this leads to the equation listed for In a, the activity of the component 1 (8AG ix/dn, = Ani, see also Fig. 7.3). 

Pezzin et al. found the same kind of behavior exhibited by polyvinyl chloride PVC in two different plasticizers, dibutyl phthalate, DBP, and dicyclohexylphthalate, DCHP [62,63]. The same two equations provided excellent fits to the PVC solution data (see Fig. 12.9). For polystyrene dissolved in w-tricresyl phosphate, TCP, additional factors were noted. 

The fractal exponent is thus significantly smaller than that of a simple random walk, and the structure of the coil is considerably more open. This result is in good agreement with experiment, as shown by the example of polystyrene dissolved in benzene, at sufficiently low concentrations that the polymers cannot penetrate each other (which would totally change the type of solution). 

U.S. Pat. 3,928,266 (1975). Linear polystyrenes dissolved in alkyd paint formulations. Semi-II IPNs. 

This law can be used experimentally to determine the excluded volume exponent v. The following data were obtained from the low-angle neutron scattering data for a polystyrene dissolved in CS2 (good solvent) and cyclohexane (poor solvent), respectively ... 

C02 Cowie, J.M.G. and McEwen, I.J., Polymer-cosolvent systems. XI. Polystyrene dissolved in mixtures of diethyl ether and nitromethane, J. Polym. Sci. Part B Polym. Phys., 25, 1501, 1987. 

This equation and the counterpart from Gibbs-DiMarzio entropy theory [8] can fit the data quite well when some of the parameters therein are taken as adjustable. They give a single Tg for the mixture. However, for polystyrene dissolved in m-tricresyl phosphate (TCP), DTA measurements [94] indicated the existence of double TgS... 

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