Poly -toluene system

LAU Lau, W.W.Y., Bums, C.M., and Huang, R.Y.M., Molecular weights and molecular weight distribution in phase eqtrilibria of the polystyrene-poly(methyl methacrylate)-toluene system,/. AppL Polym. Sci., 30, 1187, 1985. 

The latter relations are relevant for polymerization of ortho-methoxystyrene initiated in toluene by BuLi, and investigated by Smets, Van Beylen and Geerts 69). Calculations based on the subsequently obtained results show that the fraction of the active non-associated lithium poly-ortho-methoxystyrene vary in this system from 15% at 18 10 3 M concentration of lithium to 60% as its concentration decreases to 0.5 10 3 M. The experimental data published in their paper are listed in Table 3, and presented graphically in Fig. 10. 

The term IPN was first used in 1960 to describe the apparently homogeneous product obtained from styrene crosslinked with divinylbenzene. IPNs were prepared from this system by taking a crosslinked poly(styrene) network and allowing it to absorb a controlled amount of styrene and a 50% divinylbenzene-toluene solution containing initiator. Polymerisation of this latter component led to the formation of an IPN, the density of which was... 

In this case, a simple kinetic model could not be derived to explain all the experimental observations. Independently prepared hexadecyl trimethyl ammoniurn persulfate was found to be soluble in toluene/AN mixtures and to catalyze polymerization in this homogeneous system at approximately the same rate as that observed in the two phase system. This result implies that anion exchange at the interface (see below) must be essentially complete under these conditions. Factors which complicated further analysis of the mechanism included a) precipitation of poly(acrylonitri 1 e) during the polymerization ... 

Fig. 23. This photograph shows a two-phase system consisting of (top phase) toluene and (bottom phase) perfluoro-2-butyltetrahydrofuran (Fluoroinert FC-75).The dark color (brown) in the bottom phase indicates that the dendrimer-encapsulated Pd nanoparticles, complexed with poly (hexafluoropropylene oxide-co-difluoromethylene oxide) monocarboxylic acid, are selectively extracted into the fluorous phase. No detectable color was observed in the organic phase. Reprinted with permission from Ref. 103 Copyright 2000 American Chemical Society...

Negative DUV resist systems have also been developed, some of which have demonstrated extremely high sensitivity. These include poly (butyl a-chloroacrylate) (55) which is reported to be at least 500 times as sensitive as PMMA and partially chlorinated, narrow dispersity poly(p-vinyl toluene) (84), which has been imaged at 0mJ/cm in contact print-... 

The co-occurrence of nucleation and spinodal decomposition had been observed in the temperature quench experiment of poly(2,6-dimethyl-l,4-phenylene oxide)-toluene-caprolactam system, [64,65], in which the typical morphology formed by nucleation and growth mechanism was observed with electron-microscopy when the quench of temperature is slightly above the spinodal boundary. On the other hand, if the quench temperature is somewhat lower than the spinodal boundary, they observed interconnected structures as well as small droplets. 

The same type of addition—as shown by X-ray analysis—occurs in the cationic polymerization of alkenyl ethers R—CH=CH—OR and of 8-chlorovinyl ethers (395). However, NMR analysis showed the presence of some configurational disorder (396). The stereochemistry of acrylate polymerization, determined by the use of deuterated monomers, was found to be strongly dependent on the reaction environment and, in particular, on the solvation of the growing-chain-catalyst system at both the a and jS carbon atoms (390, 397-399). Non-solvated contact ion pairs such as those existing in the presence of lithium catalysts in toluene at low temperature, are responsible for the formation of threo isotactic sequences from cis monomers and, therefore, involve a trans addition in contrast, solvent separated ion pairs (fluorenyllithium in THF) give rise to a predominantly syndiotactic polymer. Finally, in mixed ether-hydrocarbon solvents where there are probably peripherally solvated ion pairs, a predominantly isotactic polymer with nonconstant stereochemistry in the jS position is obtained. It seems evident fiom this complexity of situations that the micro-tacticity of anionic poly(methyl methacrylate) cannot be interpreted by a simple Bernoulli distribution, as has already been discussed in Sect. III-A. 

The high-pressure phase behavior of polymer-solvent-supercritical carbon dioxide systems was investigated experimentally The polymers used were poly(methyl methacrylate), polystyrene, polybutadiene, and poly(vinyl ethyl ether) at concentrations ranging from 5 to 10% in mixtures with toluene or tetrahydrofuran. The experiments were conducted for temperatures from 25 to 70°C and pressures up to 2200 psi in a high-pressure cell (Kiamos and Donohue, 1994). 

Recently, experimental data of S for various liquid-crystalline polymer solutions have become available. Figure 12 illustrates the concentration dependence of S for three polymer liquid crystal systems (a) PBLG-DMF [92,93], (b) PHIC-toluene [94], and (c) poly(yne)-platinum polymer (PYPt)-trichloro-ethane (TCE) [33]. For systems (a) and (c), with the alignment made by... 

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