Methyl methacrylate infrared spectrum

Reaction of HCofPfOPh), with PMMA. A 1.0g sample of PMMA and 1.0g of the cobalt compound were combined as above. After pyrolysis at 375°C for two hours the tube is noted to contain char extending over the length of the tube with a small amount of liquid present. The gases were found to contain CO, C02, hydrocarbon (probably methane), and 0.1 Og methyl methacrylate. Upon addition of acetone, 1.0g of soluble material and 0.19g of insoluble may be recovered. The infrared spectrum of the insoluble fraction is typical of char. 

Table VII the electron-beam exposure characteristics are given for the soluble poly (triphenylmethyl methacrylate-co-methyl methacrylate)s. The sensitivity on alkaline development was strongly influenced by the copolymer composition. The highest sensitivity was obtained on the copolymer containing 93.7 mol% methyl methacrylate. The copolymer of highest sensitivity showed the 7-value of 6.3, which was nearly twice as large as that for poly(methyl methacrylate). Formation of methacrylic acid units on exposure is obvious from the infrared spectrum. However, the mechanism of the occurrence should be different from the case of the a,a-dimethylbenzyl methacrylate polymer since there are no /3-hydrogen atoms in the triphenylmethyl group, and may be similar to the case of poly (methyl methacrylate). This will be explored in the near future.

Coleman et al. 2471 reported the spectra of different proportions of poly(vinylidene fluoride) PVDF and atactic poly(methyl methacrylate) PMMA. At a level of 75/25 PVDF/PMMA the blend is incompatible and the spectra of the blend can be synthesized by addition of the spectra of the pure components in the appropriate amounts. On the other hand, a blend composition of 39 61 had an infrared spectrum which could not be approximated by absorbance addition of the two pure spectra. A carbonyl band at 1718cm-1 was observed and indicates a distinct interaction involving the carbonyl groups. The spectra of the PVDF shows that a conformational change has been induced in the compatible blend but only a fraction of the PVDF is involved in the conformational change. Allara M9 250 251) cautioned that some of these spectroscopic effects in polymer blends may arise from dispersion effects in the difference spectra rather than chemical effects. Refractive index differences between the pure component and the blend can alter the band shapes and lead to frequency shifts to lower frequencies and in general the frequency shifts are to lower frequencies. 

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. 

Figure 8. Infrared spectrum of block copolymer with methyl methacrylate...

Gel permeation chromatography (GPC) of poly(methyl methacrylate) and cellulose nitrate showed elution volume peaks at 62.5 ml for PMMA and at 87.5 for cellulose nitrate (Figure 5), due to their difference in molecular weight. A mixture of poly(methyl methacrylate) and cellulose nitrate of the same ratio as that of the graft copolymer was recorded and two peaks in elution volume at almost identical positions were observed. This shows that the constituent homopolymers retain their identity in a physical mixture. The isolated graft copolymer showed a single peak in elution volume at 80.0 ml. The second peak in elution volume is absent in spite of poly(methyl methacrylate) attached to cellulose nitrate as revealed by infrared spectrum. Hence, these results indicate that GPC can be used as a technique to differentiate between homopolymer, physical mixture, and graft copolymer. 

Infrared Spectra of Grafted Bamboo. It has been demonstrated that the occurrence of graft copolymerization of methyl methacrylate onto bamboo can be accertained by the presence of characteristic absorptions of polymer branches in the infrared spectrum (17-19), in addition to the weight increased in bamboo samples. In this study, similar procedures were conducted for the grafting of acrylonitrile. The formation of graft copolymer could easily be detected by the... 

Now we move on to consider the analysis of copolymers. There are usually two things we would like to know. First, the composition of the copolymer and, second, some measure of sequence distributions. Again, in the early years, before the advent of commercial NMR instruments, infrared spectroscopy was the most widely used tool. The problem with the technique is that it requires that the spectrum contain bands that can be unambiguously assigned to specific functional groups, as in the (transmission) spectrum of an acrylonitrile/methyl methacrylate copolymer shown in Figure 7-43 (you can tell this is a really old spectrum, not only because it is plotted in transmission, but also because the frequency scale is in microns). 

FIGURE 7-43IR spectrum of an acrylonitrile/ methyl methacrylate copolymer [redrawn from an original figure in R. Zbinden, Infrared Spectroscopy of High Polymers, Academic Press, (1964)]. 

Methacrylomtrile. a similar reaction in which methacrylonitrile (0.13 mole) was present instead of methyl methacrylate yielded gas containing 0.22% propane and 28.73% propylene. The upper layer which formed on adding the aqueous solution to 1 liter acetone was decanted. Adding ethanol to the oily bottom layer precipitated a solid which was collected on a sintered glass filter, washed with ethanol and ether, and air dried. The infrared spectrum of the reddish solid exhibited cyanide... 

FIGURE 2.48 Tlie infrared spectrum of methyl methacrylate (neat liquid, KBr plates). 

Figure 6.2 illustrates the infrared spectrum of poly(methyl methacrylate) (PMMA). The structure of PMMA is -[-CH2-C(CH3)(COOCH3)-] -. The infrared spectrum of PMMA results from the group frequencies of the C-C and C-H groups of the backbone chain, the C-C, C=0 and C-0 units of the ester group and the C-H units of the methyl substituent. The infrared assignments for this spectrum are listed in Table 6.1. 

Figure 6.2 Infrared spectrum of poly(methyl methacrylate). From Stuart, B., Modern Infrared Spectroscopy, ACOL Series, Wiley, Chichester, UK, 1996. University of Greenwich, and reproduced by permission of the University of Greenwich.

A major objective of the current research programme is to extend the treatment of polymerization kinetics based on direct measurements of monomer and radical concentrations to crosslinking systems. Conventional methods for measurement of monomer concentrations are not suitable, as they require soluble polymer. We have been able to apply our procedure for utilizing the near-infrared spectrum of the C=C bond in methyl methacrylate to systems containing ethylene glycol dimethacrylate (EGDMA) [14]. 

The infrared analysis was performed on dried potassium bromide pellets containing 0.5 mg sample in 200 mg potassium bromide. An infrared spectrum of a methyl methacrylate - glycolymethyacrylate copolymer is shown in Figure 3.7. The peaks at the wave numbers 11.02 and 5.82 jim are the most suitable ones for analysis of epoxy and carbonyl groups, respectively. Using the base line density method, the values of the absorbances at 11.02 and 5.82 xm have been determined in triplicate. The average values of the absorbances, their ratio and the glycidylmethylacrylate mole fraction determined chemically are presented in Table 3.10. 

Thus the Raman spectrum helps to identify the polarized 840 cm methyl crotonate, which is the only band between 900 and 725 cm as an in plane vibration (probably in-phase C—C—O—C stretch) and confirms the 815 cm assignment in acrylates, methacrylates, acrylic acid, and acrylamide as CH2 twist with the carbonyl wag out-of-plane band at 700-640 cm in these compounds. All the above depolarized bands have C type contours in the infrared spectra of the gas phase, verifying their out-of-plane character. 

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