Raman study of ethylene-propylene copolymers and polyethylene-polypropylene reactor blends

Raman Structural Study of Copolymers of Propylene with Ethylene and High Olefins

“…[14] However, deformation vibrations of CH 2 groups can be also observed at the same frequency in the spectra of organic molecules containing polymethylene chains. [15,16] Thus, in the spectra of the copolymers under our study at this frequency one can observe superposition of the lines, corresponding to the vibrations of both CH 2 and CH 3 groups.…”

Cover Picture: Formation of T‐Shaped versus Charge‐Transfer Molecular Adducts in the Reactions Between Bis(thiocarbonyl) Donors and Br2 and I2 Chem. Asian J. 3/2013)

“…The line at 1460 cm −1 which is observed in all our spectra corresponds to the deformation vibration of CH 3 groups of PP macromolecules 14. However, deformation vibrations of CH 2 groups can be also observed at the same frequency in the spectra of organic molecules containing polymethylene chains 15, 16. Thus, in the spectra of the copolymers under our study at this frequency one can observe superposition of the lines, corresponding to the vibrations of both CH 2 and CH 3 groups.…”

Raman Spectroscopy Study of Structurally Uniform Hydrogenated Oligomers of α-Olefins

“…Figure 10 depicts non-polarized Raman spectra of the hydrogenated 1-hexene and 1-octene oligomers and the linear alkanes C 6 H 14 , C 8 H 18 , C 12 H 26 , and C 16 H 34 in the region 2750–3150 cm −1 . By using the results of the previous work on linear alkanes [ 24 ], we assigned the bands ν s (CH 2 ) t at 2850 cm −1 and ν s (CH 2 ) g at 2874 cm −1 in the non-polarized oligomer spectra to the symmetric stretching vibrations of CH 2 units in trans and gauche conformers, respectively ( Figure 10 ). The band ν as (CH 3 ) at 2960 cm −1 is related to the asymmetric stretching vibrations of CH 3 units [ 31 , 32 ].…”

“…In addition, we display in Figure 11 the polarized Raman spectra of the linear alkanes C 6 H 14 , C 8 H 18 , C 12 H 26 , and C 16 H 34 for comparison. According to our previous Raman studies on linear alkanes (with n = 5–17) [ 24 ], the most prominent bands in the polarized Raman spectra, which are recorded at the crossed orientation of the exciting and scattered radiations, belong to the asymmetric stretching vibrations of CH 2 and CH 3 units. By comparing the polarized Raman spectra of the oligomers and alkanes, we assigned the bands ν as (CH 2 ) at ~2890 cm −1 and ν as (CH 3 ) at ~2960 cm −1 in the spectra of the oligomers to the asymmetric stretching vibrations of CH 2 and CH 3 units, respectively ( Figure 11 ).…”

“…Interesting experimental observation concerning the polarized Raman spectra of linear alkanes in the region 2800–3200 cm −1 was reported by Shemouratov et al [ 24 ], who showed that an intensity ratio of Raman bands, which are assigned to the asymmetric stretching vibrations of CH 2 and CH 3 units, monotonically grows with the increasing n of linear alkanes. These spectra were recorded at the crossed orientations of the exciting and scattered radiations.…”