Polystyrenes phenyl

For polystyrene, on the other hand, optimal parallel alignment of the respective tt systems is achieved for the liquid crystal oriented perpendicular to the rubbing direction (Fig. 6.9D). In this orientation, the backwards tilt of the polystyrene phenyl rings with inspect to the rubbing direction does not cause any out-of-plane directional asymmetry along the perpendicular axis of the liquid crystal orientation. Consequently no pretilt of the oriented liquid crystals is expected, as it is indeed observed. 

Figure 1-18 shows the synchronous 2D IR spectrum of the blend. Autopeaks observed on the diagonal positions of the spectrum near 1454 and 1495 cm represent the strain-induced local reorientation of polystyrene phenyl rings. The 1454-cm band also contains a contribution from CH2 deformation of the backbone of polystyrene [10, 11, 51]. A pair of intense cross peaks appear at the off-diagonal positions of the spectral plane near 1454 and 1495 cm , indicating the existence of a strong synchronicity between the reorientation of transition dipoles associated with these two IR bands of polystyrene phenyl side groups. 

Such a specific interaction most likely involves the lone-pair of electrons on the methoxyl oxygen atom of poly(vinyl methyl ether) and Jt-electrons of the polystyrene phenyl groups [54],... 

Figure 1-23 indicates only one methoxyl band is interacting with the polystyrene phenyl group, even though there are two distinct IR contributions of poly(vinyl methyl ether) methoxyl groups, as already shown in Figure 1-22. The other methoxyl band of poly(vinyl methyl ether) at 2824 cm is asynchronously correlated with the phenyl bands of the polystyrene component (Figure 1-24). This result suggests that while one component of poly(vinyl methyl ether) methoxyl groups...

Figure 1-23. A synchronous 2D IR spectrum of a blend comparing the reorientational motions of transition dipoles associated with the polystyrene phenyl and poly(vinyl methyl ether) methoxyl groups [57).

There are still other tests that could be done. Since the rate of oxidation of main chain deuterated polystyrene, [(phenyl)CD - CD2], is one twentieth of that for polystyrene, and ring methyl groups in the ortho and/or para position greatly reduce the rate of oxidation compared with polystyrene, a comparison of the thermograms of deuterated polystyrene and ring substituted polystyrenes could be helpful in determining the role of oxidation. 

Figure 48 Cooperative reorientations of neighboring polystyrene phenyl side groups (a) rubbery state above Tg, (b) glassy state below Tg.

Figure 1.2 shows sections of polymer chains of these three types the substituent R equals phenyl for polystyrene and methyl for polypropylene. The general term for this stereoregularity is tacticity, a term derived from the Greek word meaning to put in order. ... 

A still more intricate pattern of potential energy may be expected if the repeat units of the polymer chain carry other substituents, such as the phenyl groups in polystyrene, but these examples establish the general method for quantitatively describing the effects of steric hindrance on rotation. 

Polystyrene with its bulky phenyl substituents shows the largest amount of hindrance of the polymers listed here. 

In the methacrylate homologous series, the effect of side-chain bulkiness is just the opposite. In this case, however, the pendant groups are flexible and offer less of an obstacle to free rotation than the phenyl group in polystyrene. As chain bulk increases, molecules are wedged apart by these substituents, free volume increases, and Tg decreases. 

Figure 9.17 Plot of log [i ]M versus retention volume for various polymers, showing how different systems are represented by a single calibration curve when data are represented in this manner. The polymers used include linear and branched polystyrene, poly(methyl methacrylate), poly(vinyl chloride), poly(phenyl siloxane), polybutadiene, and branched, block, and graft copolymers of styrene and methyl methacrylate. [From Z. Grubisec, P. Rempp, and H. Benoit, Polym. Lett. 5 753 (1967), used with permission of Wiley.]...

Carbon Cha.in Backbone Polymers. These polymers may be represented by (4) and considered derivatives of polyethylene, where n is the degree of polymeriza tion and R is (an alkyl group or) a functional group hydrogen (polyethylene), methyl (polypropylene), carboxyl (poly(acryhc acid)), chlorine (poly(vinyl chloride)), phenyl (polystyrene) hydroxyl (poly(vinyl alcohol)), ester (poly(vinyl acetate)), nitrile (polyacrylonitrile), vinyl (polybutadiene), etc. The functional groups and the molecular weight of the polymers, control thek properties which vary in hydrophobicity, solubiUty characteristics, glass-transition temperature, and crystallinity. 

The anion-selective (AX) membranes (Eig. 2b) also consist of cross-linked polystyrene but have positively charged quaternary ammonium groups chemically bonded to most of the phenyl groups in the polystyrene instead of the negatively charged sulfonates. In this case the counterions are negatively... 

Being a hydrocarbon with a solubility parameter of 18.6MPa - it is dissolved by a number of hydrocarbons with similar solubility parameters, such as benzene and toluene. The presence of a benzene ring results in polystyrene having greater reactivity than polyethylene. Characteristic reactions of a phenyl group such as chlorination, hydrogenation, nitration and sulphonation can all be performed with... 

Polystyrene Poly(phenyl ethene) Poly(l-phenyl ethylene)... 

More recently, Tietze and Steinmetz (96SL667) used the patented polystyrene-resin methodology for for the solid-phase synthesis of a large number of diverse )3-keto esters 40a-h. These were reacted with phenylhydrazine in THF at room temperature to give hydrazones 41a-h that were then cychzed into 2-phenyl 5-substituted pyrazol-3-ones 42a-h by heating in toluene at 1(X)°C (Scheme 12). 

Molecular Motion in amorphous atactic polystyrene (PS) is more complicated and a number of relaxation processes, a through 5 have been detected by various techniques as reviewed recently by Sillescu74). Of course, motions above and below the glass transition temperature Tg have to be treated separately, as well as chain and side group mobility, respectively. Motion well above Tg as well as phenyl motion in the glassy state, involving rapid 180° jumps around their axes to the backbone has been discussed in detail in Ref.17). Here we will concentrate on chain mobility in the vicinity of the glass transition. 

Nickel and palladium react with a number of olefins other than ethylene, to afford a wide range of binary complexes. With styrene (11), Ni atoms react at 77 K to form tris(styrene)Ni(0), a red-brown solid that decomposes at -20 °C. The ability of nickel atoms to coordinate three olefins with a bulky phenyl substituent illustrates that the steric and electronic effects (54,141) responsible for the stability of a tris (planar) coordination are not sufficiently great to preclude formation of a tris complex rather than a bis (olefin) species as the highest-stoichiometry complex. In contrast to the nickel-atom reaction, chromium atoms react (11) with styrene, to form both polystyrene and an intractable material in which chromium is bonded to polystyrene. It would be interesting to ascertain whether such a polymeric material might have any catal3dic activity, in view of the current interest in polymer-sup-ported catalysts (51). 

The butyrate substituents are larger than those for other polymers listed, but they are not proportionately larger than the exceptional length of the structural unit of cellulose. An inspection of models shows that the three butyrate units can be accommodated about the cellulose ring with less obstruction than for the phenyl groups of polystyrene, for example. 

Successful combination of a chromatographic procedure for separating and isolating additive components with an on-line method for obtaining the IR spectrum enables detailed compositional and structural information to be obtained in a relatively short time frame, as shown in the case of additives in PP [501], and of a plasticiser (DEHP) and an aromatic phenyl phosphate flame retardant in a PVC fabric [502], RPLC-TSP-FTIR with diffuse reflectance detection has been used for dye analysis [512], The HPLC-separated components were deposited as a series of concentrated spots on a moving tape. HPLC-TSP-FTIR has analysed polystyrene samples [513,514], The LC Transform has also been employed for the identification of a stain in carpet yarn [515] and a contaminant in a multiwire cable [516], HPLC-FTIR can be used to maintain consistency of raw materials or to characterise a performance difference. 

Direct connection of pendant heteroatom to polystyrene aryl is a synthetically more difficult, but often still feasible (37), alternative. However, though bonds from phenyl to many common heteroatoms are relatively strong, resonance stabilization of partial positive charge developed on an arylated atom activates it to leave other substituents alkyl anilium salts (12) and anilines (38), as well as phenolic esters (39), are relatively easy to cleave. Aryl linkages,... 

---