Polystyrene in Solution

Since C is proportional to the product of a, i.e. the number of adsorbed molecules per phenyl group of polystyrene in solution, and the molar volume of the sorbed liquid, i.e. C = (M/d) (a/104), direct substitution into Eq. 44 gives ... 

Literature Review. The early reports on the difference in absorption behaviour of polystyrenes in solution are due to Vala and Rice (6). These authors attributed the hypochromism (decrease in absorption intensity) observed in some of the absorption bands when the spectra of isotactic and atactic polystyrenes are compared to the conformation of the polymer molecules in solution. Hypochromic... 

It is worth noting that this expression also gives the best fit for FAD curves of labeled polystyrene in solution ( 5 ). 

In Figure I we compare emission spectra for polystyrene in dilute solution and as a solid film, and for a model monomer, ethylbenzene, in dilute solution. Polystyrene in solution exhibits, in addition to a monomer-like emission, a broad excimer emission maximizing at emission spectrum is not unique to high molecular weight polymer. Indeed, 1,3-diphenylpropane exhibits (la,8) very similar total emission spectra. The excimer emission lifetime is (4) 12.5 ns in CH2CI2 at room temperature, while monomer-like emission decay and excimer emission rise times are reported (2) to be of the order of a nanosecond in cyclohexane solution. 

The photophysical behaviour of polystyrene in solution can be explained by a Birks-type scheme in which k[)M is an average rotational constant whereby a 1 3 intramolecular excimer is formed. On this basis. 

Typical results in the graft polymerization of poly (styrene-alt-maleic anhydride) onto polystyrene in solution without a radical catalyst are shown in Table I. Analogous results are obtained in the presence of a radical catalyst. 

Rabek [504] found that anthracene sensitizes the degradation and photo-oxidation of polystyrene in solution. It also sensitizes the degradation of cis-polybutadiene in benzene solution. 

Light is strongly scattered by polystyrene in solution and the refractive index of the solution is very dependent of the mass concentration... 

Polystyrenes in solutions under ideal conditions (0 solutions) are expected to exhibit... 

Over 200 references describing spontaneous, and chemically initiated styrene polymerization chemistry are reviewed with special emphasis on advances taking place in the past decade. The review is limited to chemistry useful for making amorphous high molecular weight polystyrene in solution polymerization processes. Chemical initiators have been categorized into three basic groups as follws 1) anionic 2) mono-radical and 3) diradical. Analytical techniques used for determination of free radical polymerization kinetics and mechanisms are also discussed. 

The basic principle of their suggestion was formulated as intensive crosslinking of polymeric chains, in particular, chains of polystyrene, in solution or in swollen state by rigid bridges. This approach led to the creation of a new type of polymeric materials with special structure and peculiar properties that were not characteristic of any known types of networks. Therefore, a new term was needed to characterize these new materials we have called these new polymers hypercrosslinked polystyrene. ... 

This decisive topological factor largely accounts for the fact that, at equivalent degree of crosslinkings, the swelling abilities of the products of post-crosslinking linear polystyrene in solution or swollen styrene—DVB copolymer are much higher than that of conventional gel-type... 

CHARACTERISTIC TIME OF THE SEGMENTAL MOTION OF POLYSTYRENE IN SOLUTIONS AND MELT... 

TABLE 7 Characteristic parameters of segmental motion of polystyrene in solutions and melt. 

In order to illustrate the d5mamic properties of the polystyrene in solutions and melt in Table 8 are given the numerical estimations of the characteristic times of segmental and translational motions of the polystyrene... 

The relaxation with m = 0 approximates to the behaviour of polystyrene in solution. Once the value of n is greater than 5 the motions have become decoupled and the relaxation of the alkane block is almost independent of that of the styrene dimer. This implies that the size of the group in solution that is required for co-operative motion is approximately 5-6 carbon atoms. Similar analysis has been carried out on solid-state relaxations and it is generally found that the ot process involves motion of between 6 and 10 bonds depending on the polymer system. If we consider the co-operative motion of such an element it is possible to envisage that rotation about the backbone can occur without the... 

Ozonization of polystyrene in solution results in cross-linking as well as chain scission. The major products are carboxylic acids. 

Figure 4.41. Tracer diffusion coefficient Di of polystyrene in solutions of matrix polymer, poly(vinyl methyl ether), in o-fluorotoluene at various concentrations of the matrix polymer, plotted as a function of molecular weight Mps of polystyrene. The solvent is isorefractive with the matrix polymer. The concentration of the matrix polymer and the slope obtained in the best fitting by a power law (straight line) are indicated adjacent to each plot. (From Ref. 53.)...

VSH Vshivkov, S.A. and Safronov, A.P., Coil-globule transition of polystyrene in solution (Russ.), Vysokomol. Soedin., Ser. B, 37, 1779, 1995. 

D. R. Bauer, J. I. Brauman, and R. Pecora. Depolarized Rayieigh spectroscopy studies of relaxation processes of polystyrenes in solution. Macromolecules, 8 (1975), 443 51. 

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