Styrene infrared spectrum

The formation of block copolymers from styrene-maleic anhydride and acrylic monomers was also indicated by pyrolytic gas chromatography and infrared spectroscopy. A comparison of the pyrograms of the block copolymers in Figure 7 shows peaks comparable with those obtained when mixtures of the acrylate polymers and poly(styrene-co-maleic anhydride) were pyrolyzed. A characteristic infrared spectrum was observed for the product obtained when macroradicals were added to a solution of methyl methacrylate in benzene. The characteristic bands for methyl methacrylate (MM) are noted on this spectogram in Figure 8. 

Japanese investigators reported that liquid sulfur dioxide polymerizes styrene derivatives (e.g., p-methyl styrene, a-methyl styrene) (19). Unfortunately, the experiments were not executed under rigorously anhydrous conditions (high vacuum) so that the possibility for proton (e.g., sulfurous or sulfuric acid) initiation exists although the authors seem to believe that S02 is the catalyst, probably by the following process 2S0a SO2 +SO e. The cationic nature of the mechanisms was proven by the facts that no polysulfones formed, that the polymerization was inhibited by bases, and that free radical inhibitors did not affect the reaction. These authors also claim that formaldehyde is polymerized by sulfur dioxide to a product which does not contain sulfur and whose infrared spectrum closely resembles that of a low temperature sample. 

Hydroxyethyl functionalities can be anchored to poly(styrene-DVB) by reacting lithiated resin with ethylene oxide (15). A THF suspension of lithiated resin (2 g in 50 ml) was cooled to -80°C, and 15 ml of ethylene oxide at -80°C were added with a transfer pipet. The mixture was brought to room temperature (in about 3 hr) and the beads were separated by filtration, washed successively with THF H20 (3 1), 10% HC1, H2O, THF, and ether, and then vacuum dried at 70°C. The infrared spectrum showed an OH absorption. 

The Infrared spectrum of the SMA copolymer labeled SMA-2, is consistent with other SMA copolymer spectra published (33). However, the absorption peaks in the range of 1700 - 1820 cm indicate that this copolymer has been partially esterified to yield a half/acid ester of maleic anhydride which should exhibit peaks in the range of 1700 - 1725 cm"l and 1735 -1750 cm (Figure 3). The small absorption bands at 1780 and 1820 cm indicate the presence of a small amount of unreacted maleic anhydride. These data appear to be consistent for those of a styrene-maleic anhydride copolymer reported by Muskat (34). The carbon, hydrogen, oxygen analyses indicate that this polymer is a half/acid ester of a 90% styrene/10% maleic anhydride copolymer wherein theoretical values of C, H and 0 are 88.89%, 7.017. and 2.58% versus values of 89.14%, 7.68% and 2.81% found for C, H and 0, respectively. The solubility parameter was found to be equal to 9.47 H. 

The structure of the product from a mixture of styrene and 1-bromo-butane, as far as is shown by the infrared spectrum of Figure 6, is the same as that from styrene alone. 

Carbon suboxide s susceptibility to radical polymerization was also examined by an attempted copolymerization of equimolar quantities of carbon suboxide and styrene initiated by azobisisobutyronitrile at 60°C in toluene solution. The infrared spectrum of the polymeric product was identical with that of a styrene homopolymer control, and no carbonyl absorption was detected. 

Where the polymer material is a copolymer it is often possible to obtain a measurement of the relative amounts of the various monomer components from an infrared spectrum. For example, with an ethylene-vinyl acetate copolymer the relative heights of absorption bands from both the ethylene and vinyl acetate are measured and ratioed with the spectrum recorded in the absorbance mode. The most convenient absorbance bands are 720 cm for polyethylene and 1235 or 1740 cm for vinyl acetate. Copolymers of known composition are required for calibration. It is possible to obtain an assessment on the butadiene and acrylonitrile contents in styrene/ butadiene/acrylonitrile copolymers. The bands usually used are for styrene 1600 cm, for acrylonitrile 2240 cm and for butadiene 996 cm... 

Brako and Wexler [122] have described a useful technique for testing for the presence of unsaturation in polymer films such as polybutadiene and styrene-butadiene. They expose the film to bromine vapour and record its spectrum before and after exposure (Figure 3.12). This results in marked changes in the infrared spectrum. Noteworthy is the almost complete disappearance of bands at 13.691,10.99,10.36, and 6.10 pm associated with unsaturation. A pronounced band possibly associated with a C-Br vibration appears at 12.02 pm which is due to exposure to bromine vapour. Exposure of butadiene-styrene copolymer (Figure 3.12) to bromine vapour results in the disappearance of bands at 10.99 and 10.36 pm associated with unsaturation in the butene component of the copolymer. Some alteration of the phenyl bands at 14.28 and 10.37 pm is evident. The loss of a band at 6.45 pm and the appearance of a band at 5.88 pm are probably due to the action of acidic vapours on the carboxylate purifactant of the latex. 

FIGURE 2.27 The infrared spectrum of styrene (neat liquid, KBr plates). 

One infrared spectral method used for the determination the monomer units of SBR is known as Hampton s method [63]. This method utilizes the characteristic monosubstituted aromatic band intensity at 699 cm (A ) for the determination of styrene unit composition, and the scheme defined as Morero s method (see seetion on polybutadiene and polyisoprene) is used to determine the butadiene moiety. As noted in the section on polybutadiene, the 1,4-cw, 1,4-trans, and 1,2-addition components appear in the IR spectrum at 724, 965, and 910 cm . ... 

Infrared spectra of polymers are also obtained in a rapid screening mode by pulse pyrolysis-FTIR using solid samples (ca. 0.1-0.5 mg) that are placed "as is" into the Pyroprobe-Pyroscan-FTIR system for semi-quantitative, qualitative information. The vapor phase IR spectrum in Figure 3a is that from a pulse pyrolysis (750 C for 10 sec) of a 100 mg sample of solid poly(styrene). The thermal decomposition of poly(styrene) to its slyrene... 

The formulation of a sulfur-vulcanized styrene-butadiene rubber (R2) mainly contains the rubber polymer and precipitated silica as filler the rest of the components are minor in amount, but they are important to impart adequate vulcanization and protect the rubber from the degradation under use (mainly paraffin wax). The paraffin wax acts as a physical protecting agent against ozone by migration to the rubber surface (Romero-Sanchez and Martin-Martinez 2004). O Figure 43.6 shows the attenuated multiple total internal reflection-infrared spectroscopy (ATR-FTIR) spectrum of the R2 bulk. The main bands correspond to rubber (styrene and butadiene) and silica, and the presence of CH2 moieties are minor corresponding to the paraffin wax. However, the ATR-FTIR spectrum of the R2 surface shows the main bands due... 

To get a sense of how powerful the use of infrared group frequencies is, an examination of the polymerization of styrene to polystyrene by infrared will be carried out. The starting monomer is the upper spectrum shown in Figure 5.29. It will be treated as if the spectrum were an unknown substance. 

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