Polystyrene in carbon tetrachloride

Saito et al. [107] investigated ozonolysis of polystyrene in carbon tetrachloride. Their results indicated the formation of carboxylic acids and,... 

Odajima (20) has independently reported and commented on the NMR spectrum of polystyrene in carbon tetrachloride solution. Unfortunately, the peaks observed were wrongly assigned. 

Polystyrene films were prepared by doubly dipping the substrate—a silicon wafer previously cleaned by pure solvents and etched by hydrogen fluoride—into solutions of 1 gL of pure polystyrene in carbon tetrachloride (spectroscopic grade) and allowing the solvent to evaporate. Thickness of the films thus obtained was estimated to be of the order of 100 A by elastic recoil diffiision analysis (ERDA) measurements [122]. 

For semi-dilute solutions of polystyrene in carbon tetrachloride and deuter-... 

Alp. 100 solution of polystyrene in carbon tetrachloride is freeze-dried. 

Our absorbance data are also in excellent agreement with those already published in the literature. For instance, Takahashi et al. have measured r to be between 1.0 and 1.2 mg m" for polystyrene in carbon tetrachloride adsorbed onto a chromium plate. Using ellipsometry, they were also able to measure an ellipsometric layer thickness of 200 A for M = 1.10 x 10. It is easy to show that = 2 < z >. Therefore, this corresponds to a < z > value of 100 A whicn compares favorably to our own value of 68... 

Tables 5.4 and 5.5 predict that unvulcanised natural rubber (8 = 16.5) will be dissolved in toluene (8 = 18.2) and in carbon tetrachloride (8 = 17.5) but not in ethanol (8 = 26.0), all values being in units ofMPa. This is found to be true. Similarly it is found that there is a wide range of solvents for polystyrene in the solubility parameter range 17.2-19.7 MPa. ...

Chloroethyl)polystyrenes and (iodoethyl)polystyrenes are each prepared from the alcohol by common reagents in a single step without complications, but one-pot procedures fail to produce completely pure bromide, which must be prepared from the tosylate by assisted halide exchange (57). The preparation of (toluenesulfonyloxyethyl)polystyrene itself, if performed in ice-cold pyridine as for the free analogue (64, 65), required a week to complete (67) if quaternary ammonium and other side-products (68) are to be avoided. In contrast, with non-nucleophilic diisopropylamine (69) as acid acceptor instead of pyridine, (hydroxyethyl)polystyrene and toluene-sulfonyl chloride need only be refluxed in carbon tetrachloride for a few hours to give the desired tosic ester as sole product in quantitative yield (57). 

Cross-linked polystyrene can be directly brominated in carbon tetrachloride using bromine in the presence of Lewis acids (Experimental Procedure 6.2 [55-58]). Thal-lium(III) acetate is a particularly suitable catalyst for this reaction [59]. Harsher bro-mination conditions should be avoided, because these can lead to decomposition of the polymer. Considering that isopropylbenzene is dealkylated when treated with bromine to yield hexabromobenzene [60], the expected products of the extensive bromi-nation of cross-linked polystyrene would be soluble poly(vinyl bromide) and hexabromobenzene. In fact, if the bromination of cross-linked polystyrene is attempted using bromine in acetic acid, the polymer dissolves and apparently depolymerizes [61]. 

Fig. 3. NMR spectra of (a) cumene (10% solution in carbon tetrac loride) and (6) polystyrene Pn 500, 15% solution in carbon tetrachloride)...

Photochlorimtion of polystyrene involves replacement of hydrogens at the a and P positions.was believed in the past that the chlorine atoms react preferentially at the a position until the chlorine content of the product reaches 20% by weight. After that, it was thought that the chlorines are introduced into the other position. Later, however, this was contradicted.In fact, when polystyrene is photochlorinated in carbon tetrachloride at low temperatures, like 13 C, it is substituted equally at both positions. At higher temperatures, like 78 C, substitutions at the p position actually predomihate. ... 

Patticini [8] has described an IR method for the determination of 1-8% of mineral oil in polystyrene (PS). In this method the PS sample is dissolved in carbon tetrachloride, together with known mineral oil standards. The solutions are evaluated by measurements made between 3100 and 3000 cm using a spectral subtraction technique. 

The rate of the photo-oxidative degradation of polystyrene in halomethanes increases in the order methylene chloride < chloroform < carbon tetrachloride, i.e. it increases with increasing electron affinity of the solvent [279]. Photodegradation of poly(a-methylstyrene) in carbon tetrachloride by... 

Consider the following example of polystyrene homopolymerisation in carbon tetrachloride solvent ... 

Styrene is a colorless Hquid with an aromatic odor. Important physical properties of styrene are shown in Table 1 (1). Styrene is infinitely soluble in acetone, carbon tetrachloride, benzene, ether, / -heptane, and ethanol. Nearly all of the commercial styrene is consumed in polymerization and copolymerization processes. Common methods in plastics technology such as mass, suspension, solution, and emulsion polymerization can be used to manufacture polystyrene and styrene copolymers with different physical characteristics, but processes relating to the first two methods account for most of the styrene polymers currendy (ca 1996) being manufactured (2—8). Polymerization generally takes place by free-radical reactions initiated thermally or catalyticaHy. Polymerization occurs slowly even at ambient temperatures. It can be retarded by inhibitors. 

Another serious effect occurs with liquids which are not in themselves solvents but which may wet the polymer surfaces. These facilitate relief of frozen-in stresses by surface cracking which can be a severe problem in using many injection and blow mouldings with specific chemicals. Examples of this are white spirit with polystyrene, carbon tetrachloride with polycarbonates and soaps and silicone oils with low molecular weight polyethylenes. 

Reaction Scheme of CMS Resists. The transient absorption spectrum shown in Figure 6 and observed for irradiated CMS films is mainly composed of two components as based on pulse radiolysis data of solid films of CMS and polystyrene, and CMS and polystyrene solutions in cyclohexane, chloroform, and carbon tetrachloride. An absorption with a maxima at 320 nm and 500 nm as due to the charge transfer radical-complex of the phenyl ring of CMS and chlorine atom (see Figure 14) and an absorption with maxima at 312 and 324 nm is due to benzyl type radicals (see Figure 11). 

Adding the proton-free solvent carbon tetrachloride to polystyrene, one observes the relationship between line width and temperature as shown in Figures 5a and 5b. For the system polystyrene with 21.5% carbon tetrachloride the absorption curves for various temperatures are plotted against the field strength (2) in gauss. As the temperature decreases, the line broadens, as shown more clearly in... 

---