Polymer films molecular assignment

Calculations. The spectrum of a typical high cis-1,4 polymer sample is shown before and after irradiation in Figure 1 and that of a trans-1,4 polymer film in Figure 2. The significant infrared bands are listed in Table II for all of the polybutadienes, with the assignments to the various modes of molecular oscillation as developed by Binder (2). The bands used to estimate quantitative changes in the olefin groups were those at 740 cm."1 for the cis isomer, 967 cm."1 for the trans isomer, and 910 cm."1... 

Loss tangent (tan 5) of dynamic viscoelasticity of a polymer directly reflects the mobility of polymer molecular diains. Figure 3 shows the temperature dependence of the tan S for the PS film prepared for the plasma treatment. The tan S began to increase to 70°C and had peaked at 100°C. The peak was assigned to a> relaxation, wluch allows the motion of the polymer segment in the tnilk and corresponded to the Tg determined by thermal analysis. Thus the critical temperature appeared as the temperature at which the motion of the polymer segments in the bulk began to be allowed. 

Semicrystalline polymers, such as polyethylene [45-47] and polypropylene [5, 48], may also be studied by using the 2D IR technique. By taking advantage of the enhanced spectral resolution of 2D IR, overlapped IR bands assigned to the coexisting crystalline and amorphous phases of semicrystalline polymers can be easily differentiated. Sueh differentiation has become especially useful, for example, in the study of blends of high-density polyethylene and low-density polyethylene [47], Here it was found that blends of polyethylenes are mixed at the molecular scale only in the amorphous phase, while each component crystallizes separately. In this section, an example of a 2D IR analysis applied to a film of linear low-density polyethylene is discussed [46]. 

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