In Figure 3, the spectra in www.selleckchem.com/products/FTY720.html the region 1300�C750/cm collected on some of the samples analyzed in this work are reported. In particular, in the left plot of Figure 3 the spectra of two samples solidified at two cooling rates (the lowest, 0.3K/s, and the fastest, 110K/s) are compared. For i-PP, several absorption bands of the crystalline and amorphous fraction have been identified [17], and the commonly adopted ones are highlighted in Figure 3. The most defined and isolated one is at 841/cm due to CH2 rocking and CH axial bending. Another band partially overlapping the first one is the band at 998/cm, due to CH3 equatorial rocking, C�CCH3 stretching, CH, bending and CH2 twisting. All the mentioned bands are sensitive to the order of long helicoidal chains, and then they measure the contribution to order of �� phase as well as of �� phase and of mesomorphic structures.

Thus crystallinity degree as measured by IR is an average crystallinity degree: it is not possible to discriminate between contribution of different phases. In plot (a) of Figure 3 it can be noticed that the peaks corresponding to the amorphous phase are slightly more pronounced, and conversely the peaks corresponding to the crystalline phase are slightly less pronounced, for the sample solidified at the highest cooling rate. The effect is more evident on zooming in a narrower region, as done in inset of the plot (a) of Figure 3. This indicates that, as expected, crystallinity slightly decreases on increasing cooling rate.

The effect of recycling steps is analyzed in plot (b) of Figure 3, where samples undergoing different recycling steps and solidified at the fastest applied cooling rate (of the order of 100K/s) are compared. The spectra look quite similar with some differences for the shoulder at 1158/cm (assigned to the amorphous phase [18]) which is more pronounced for the sample which underwent 10 steps of recycling and for the peak at 888/cm which increases on increasing the recycling steps. This latter peak Carfilzomib is attributed to the external vinylidene groups, which are formed by disproportionation between free radicals formed by rupture of the polymer backbone and are an index of thermal oxidation [19]. The increase of the peak at 888/cm is a clear indication of thermal degradation of the material on increasing the recycling steps.Figure 3FTIR spectra collected on some of the samples analyzed in this work. In plot (a) spectra of virgin samples solidified at two cooling rates; in plot (b) spectra of samples undergone different recycling steps and solidified at the fastest applied cooling …For a quantitative determination of the crystallinity degree, the FTIR absorbance spectra were analyzed applying Lambert and Beer’s law to selected peaks [20].