71 and 4.01 ppm Selleckchem Luminespib were the characteristic resonances of the coterminous two methylene protons of -CH2CH2- in DEA unit, and
the signals at 1.05 and 2.59 ppm belonged respectively to the end methyl and methylene protons of -CH2CH3 in DEA unit. The degree of polymerization of PCL (x), PDEA (y) and PPEGMA (z) and the molecular weights (M n,NMR) were calculated from the integration ratio values of signal (g) to (a) (I g/I a), signal (n) to (g) (I n/I g), and signal (r) to (g) (I r/I g), respectively, as summarized in Table 1. Figure 2 1 H NMR spectra of (PCL) 2 -Br 2 (A) and (PCL) 2 (PDEA- b -PPEGMA) 2 (B) in CDCl 3 . Table 1 GPC and 1 H NMR data of (PCL) 2 (PDEA- b -PPEGMA) 2 polymers Entry Samplea M n, GPC b M w/M n b M n,
NMR c M n, RealIR d 1 (PCL24)2(PDEA16-b-PPEGMA19)2 14,888 1.28 29,617 28,200 2 (PCL24)2(PDEA37-b-PPEGMA15)2 12,692 1.19 33,977 34,300 3 (PCL38)2(PDEA26-b-PPEGMA11)2 18,302 1.19 29,530 28,524 4 (PCL38)2(PDEA17-b-PPEGMA9)2 13,586 1.35 24,480 24,614 5 (PCL32)2(PDEA25-b-PPEGMA22)2 19,389 1.41 37,766 38,114 6 (PCL32)2(PDEA20-b-PPEGMA19)2 18,707 1.37 32,907 32,120 aThe subscripts find more of PCL, PDEA and PPEGMA were the DP of PCL (x), PDEA (y) and PPEGMA (z) calculated from 1H NMR spectrum; bmeasured by GPC in THF; ccalculated by the equations M n, NMR = (114 × x +185 × y + 475 × z ) × 2 + 434; dcalculated by monomer conversion from the ReactIR. Figure 3 showed that the reaction process could be easily in situ monitored by ReactIR iC10 via detecting the change of absorbance at 938 cm−1 (=CH2 wags of the DEA and PEGMA) [36, 37]. It
could be seen that the absorbance at 938 cm−1 decreased as the polymerization of DEA proceeded. Since the absorbance of DEA almost kept constant at 5 h, the second monomer PEGMA was added to continue the polymerization for another 20 h until the absorbance remained unchanged again in Figure 3A. From the change of absorbance at 938 cm−1 in situ monitored by react infrared spectroscopy, we could calculate the conversions of DEA and PEGMA Montelukast Sodium during the ARGET ATRP presented in Figure 3B. And thus the molecular weights (M n, ReactIR) of the (PCL)2(PDEA-b-PPEGMA)2 could be calculated from the conversions of DEA and PEGMA, which was seldom reported before. The M n, ReactIR listed in Table 1 were in good agreement with the M n,NMR, suggesting that (PCL)2(PDEA-b-PPEGMA)2 with different PCL/PDEA/PPEGMA contents were well-defined. The semilogarithmic plots of ln([M]o/[M]) vs. time from Figure 3C showed linear time dependency for both DEA and PEGMA during their polymerization, indicating that a good control of the polymerization process was achieved in the current work. Figure 3 In situ monitored by ReactIR iC10. The absorbance at 938 cm−1 (=CH2 wags) (A) monomer conversion versus time curves (B) and kinetic plots (C) for continuous ARGET ATRP of DEA and PEGMA.