Sensitivity PMMA, spectral

Figure 4. Spectral sensitivity data of PMMA and sensitized PMMA obtained by the equipment shown in Figure 3 (A) PMMA (B) PMMA -f- p-teit-butyl benzoic acid (C) PMMA + 2,4-di-tert-butylphenol (D) PMMA + 2,4,6-tri-teit-butyl-...

Figure 9. Spectral sensitivities of PMMA and sensitized PMMA ( ) PMMA (tH) PMMA + p-tert-bvtyl benzoic acid (A) PMMA -)- 2,4-di-tert-butylphenol (Q) PMMA -)- 2,4,6-tri-tert-butylphenol...

Tacticity determination of vinyl polymer by 1H NMR spectroscopy was first achieved for PMMA by Nishioka169 and Bovey.170 13C NMR chemical shifts of carbons in PMMA show higher sensitivities to longer stereosequences.163 171 173 The carbonyl carbons in many polymethacrylates exhibit a splitting pattern similar to that in PMMA. However, a recent report on 13C NMR spectra of polymers of various chlorophenyl methacrylates indicates that the number and positions of the chloro substituent strongly affect the spectral patterns, and the carbonyl carbon signal of poly(2,4,6-trichlorophenyl methacrylate) does not show a splitting due to tacticity.174... 

For thin layers of PMMA on the surface of crystal KRS-5, it was established that at changing depths of radiation penetration, the spectra vary in regard to the intensity of some bands. Complex changes in spectra and the intensity of conformation-sensitive bands are observed at the distances of 1.5-2 pm from the surface. The analysis of spectral data allows us to understand that in the surface layer a narrowing of conformational set of macromolecules takes place and a more regular arrangement of some chain fragments arises. The solid surface... 

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