Styrene-2- ethyl

Copolymers belonging to the case c) were found to be those of styrene with 1-vinyl naphthalene (crystallinity appears for molar contents of the latter lower than 50% by moles), -ethyl styrene and -bromo styrene (crystallinity appears for contents of the latter comonomers up to 10—15% by moles), -chloro styrene and -methyl styrene (crystallinity is shown for contents up to 30 and >50% by moles respectively of the latter). It is remarkable that in all these cases the introduction of bulkier monomeric units into the polystyrene chain always causes a fairly considerable increase only in the equatorial unit cell dimensions. Cases a and b are shown in Fig. 3 and in Fig. 4. 

Support-bound stannanes have been prepared from phenyllithium bound to macro-porous polystyrene and chlorostannanes [14,41], by treatment of support-bound alkyl chlorides with lithiated stannanes [21,41], and by radical or palladium-mediated addition of stannanes to alkenes and alkynes (Figure 4.7 [42-47]). The chloride of poly-styrene-bound chlorostannanes can be displaced by treatment with arylzinc reagents, thereby yielding resin-bound arylstannanes [46]. Polystyrene-bound stannanes have also been prepared by copolymerization of 4-[2-(dibutylchlorostannyl)ethyl]styrene with styrene and divinylstyrene [48],... 

Scheme 14 Mechanism of photo-oxygenation of (, ( -dim ethyl styrene.

The insolubilized DIOP catalyst (34) was found to be rather ineffective for the asymmetric hydrogenation of oleflnic substrates the hydrogenation of a-ethyl-styrene proceeded readily but gave (-)-R-2-phenylbutane with an optical purity of only 1.5%. Methyl atropate was hydrogenated to (+)-S-methylhydratropate (2.5% ee). The soluble DIOP catalyst gave 15 and 17% ee, respectively, for the same reductions. The optical purity of the products was lower when recovered insolubilized catalyst was used. There was no reduction of a-acetamidocinnamic acid in ethanol-benzene with the insolubilized catalyst, presumably due to the hydrophobic nature of the polymer support causing it to shrink in hydroxylic solvents. 

Two features are characteristic for the pyrolysis of this copolymer, crosslinking and the existence of mixed isomers regarding the position of the ethyl group. Mixed isomers are obvious from the formation of considerable levels of both 4-ethyl-1-ethenylbenzene and 2-ethyl-1-ethenylbenzene. These compounds indicate that the copolymer was made using 4-ethyl- and also 2-ethyl-styrene. The second feature is the noticeable level of 1,4-diethenylbenzene (about 9%). Some of the bifunctional units will generate 4-ethyl-1-ethenylbenzene and 1,4-diethylbenzene. The formation of the bifunctional monomer has a lower yield compared to that of styrene for the same content in the copolymer. 

Boeseken et a/. first studied the kinetics of such reactions the first report dealt with the reaction of perbenzoic acid with derivatives of styrene in chloroform solution and despite the ease of decomposition of the reagent, styrene was proved to react less rapidly than /3-methyl- or /3-ethyl-styrene. In the second paper, the rates of reaction of a number of olefins with peracetic acid in acetic acid were shown to increase with substitution of the olefinic bond, viz. 

Poly[styrene-codivinylbenzene-co-chloromethylstyrene-co-4-[2,2-bis-(ethoxycarbonyl)ethyl]styrene] 2.3 g (100 mmol) sodium were suspended in 150 mL of dry, boiling toluene. 16 g (100 mmol) diethylmalonate was added dropwise. After all the sodium had reacted, 10 g of the chloromethylated polystyrene (41 mmol of CH2CI) was added and the mixture was refluxed for 6 h. After cooling, the resin was filtered, washed with methanol and acetone, and then treated with acetone in a Soxhlet apparatus. The product was dried at 80 °C in vacuo. The polymer eontains 7.1 mmol oxygen per g polymer (11.32 wt. % O) which corresponds to 1.78 mmol malonic ester groups per g polymer. The Cl content is 0.84 mmol per g polymer (2.99 wt. % Cl). IR (KBr) 1736 cm (v C=0 ester). 

Synonyms Benzene, (1-methylethenyl)-, homopolymer Methylstyrene homopolymer a-M ethyl styrene polymer Empiricai (CnHio)n Formula [CH2C(CH3)(C8H5)]n Properties M.w. 685-960 dens.1.075 (15.6 C) m.p. 118-141 C ref. index 1.61 (20 C)... 

Nakagawa and co-workers [18] used techniques based on high resolution Py-GC and Py-GC and TGA to measure thermal degradation of chloromethyl substituted polystyrene. A typical TGA weight loss curve is shown in Figure 4.1. Degradation starts at 200 "C and peaks at 400 °C. Typical pyrolysis products of chloromethylated styrene-divinyl benzene (St-DVB) copolymers are the monomers, dimers and trimers of styrene, p-methyl styrene, and divinyl and ethyl styrene. For styrene chloromethyl St-DVB copolymers, in addition to the above, /-methyl styrene monomer and m- and p-chloromethyl styrene monomers are also present in pyrolysates. 

In the continuous mass polymerization of acrylonitrile butadiene styrene (ABS) and high impact polystyrene (HIPS), the thermal polymerization of styrene and alpham-ethyl-styrene is of increasing concern [3]. Scale-up issues remain, especially for the... 

In the pyrograms of Cl-MST-DBV copolymers (Figure 1.5), styrene monomer, dimer and trimer characteristics of styrene sequences are commonly observed, and their peak intensities decrease as the chlorine content increases. Additionally, decreases in the peak intensities of the meta and para isomers of DVB and ethylstyrene as a function of chlorine content indicate that Friedel-Crafts chloromethylation also occurs in DVB and ethylstyrene moieties in the copolymer. The greater decreases in the peak intensities of the meta isomers than those of the para isomers suggest that the Friedel-Crafts chloromethylation occurs more selectively on the meta isomers of DVB and ethyl styrene units. p-Methylstyrene and its dimer characteristic of chloromethylated styrene units are observed in the pyrograms of chloromethylated samples since the Friedel-Crafts chloromethylation occurs mostly on the para position of the styrene units (Figure 1.6). 

We were able to demonstrate the mechanism of the carbocationic polymerization using substituted styrenes by copolymerization and showing that the reactivities of these monomers obeyed the classical Hammit free energy equation. In addition, we demonstrated steric factors involved in cationic polymerization through the copolymerization method. We demonstrated that 3-niethyl styrene would copolymerize whereas 3-ethyl styrene would not. 

Some specific recent applications of the GC-MS technique to various types of polymers include the following PE [49,50], poly(l-octene) [51], poly(l-decene) [51], poly(l-dodecene) [51], 1-octene-l-decene-l-dodecene terpolymer [51], chlorinated polyethylene [52], polyolefins [53, 54], acrylic acid methacrylic acid copolymers [55], polyacrylates [56], styrene-butadiene and other rubbers [57-59], nitrile rubber [60], natural rubbers [61, 62], chlorinated natural rubber [63, 64], polychloroprene [65], PVC [66-68], silicones [69, 70], polycarbonates [71], styrene-isoprene copolymers [72], substituted PS [73], polypropylene carbonate [74], ethylene-vinyl acetate copolymers [75], Nylon [76], polyisopropenyl cyclohexane a-methyl styrene copolymers [77], m-cresol-novolac epoxy resins [78], polymeric flame retardants [79], poly(4-N-alkyl styrenes) [80], polyvinyl pyrrolidone [81], vinyl pyrrolidone-methyl acryloxysilicone copolymers [82], polybutylcyanoacrylate [83], polysulfide copolymers [84], poly(diethyl-2-methacryloxy)ethyl phosphate [85], ethane-carbon monoxide copolymers [86], polyetherimide [87], bisphenol A [88], ethyl styrene [89], styrene-isoprene block copolymer [89], polyvinyl alcohol-co-vinyl acetate [90], epoxide thiol [91], maleic acid-propylene copolymer [92], P-hydroxy butyrate-P-hydroxy valerate copolymer [93], polycaprolactams [39,94], PS [95,96], polypyrrole [95,96], polyhydroxy alkanoates [97], poly(p-chloromethyl) styrene [81], polybenzooxazines and siloxy substituted polyoxadisila-pentanylenes [98,99] poly benzyl methacrylates [100], polyolefin blends after ageing in soil [101] and polystyrene peroxide [43]. 

Hydroxy-2-propyl)styrene [4-vinylphenyl dimethyl carbinol, a,a-dimethyl(4-vinyl)benzyl alcohol] and 4-(l-hydro ethyl)styrene [4-vinylphenyl methyl carbinol, o>-methyl(4-vinyl)benzyl alcohol] were synthesized according to Scheme IV by reacting 4-vinylphenylmagnesium chloride with acetone and acetaldehyde, respedively, purified by column chromatography, and subjected to radical polymerization with benzoyl peroxide (BPO) or 2,2 -azobis(isobu oni-trile) (AIBN) in tetrahydrofuran (THF) at 60 °C. The monomer 14) and polymer syntheses 15,16) can be found in the literature. In our polymerizations the monomer concentration was kept low (6 mL THF/g monomer) and the conversions were also kept relatively low ( 70 %) to avoid gelation. The unreacted monomers were removed by column chromatography and the polymers were purified by precipitation in water. Simple precipitation procedures alone did not remove the unreacted monomers. 

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