PVPh/PMA

Fig. 10.16. (A) 2D H—HETCOR pulse sequence and (B) 2D HETCOR spectrum for PMA/PVPh = 1/1 cast from methyl ethyl ketone. The interpolymer cross-peak between the carbonyl carbon of PMA (b) and the hydroxyl protons of PVPh (a) is appreciable. (Reprinted with permission from Ref. [26]. 1994 John Wiley, New York.)...

Mirau and White applied the HETCOR pulse sequence to PMA/PVPh, PMMA/PVPh and PC/polycaprolactone (PCL) blends [26, 124]. Figure 10.16(b) shows the HETCOR spectrum for PMA/PVPh = 1/1 cast from methyl ethyl ketone. The combined use of WIM-24 and MAS allows CP for H and C spins in close proximity, therefore, most of the cross-peaks appear between directly bonded C— H pairs. Interestingly, a cross-peak was observed for the nonprotonated carbonyl carbon of PMA. The spectrum shows... 

The original HETCOR experiment has been modified to incorporate the spin-diffusion period after the evolution period to examine the miscibility of PC and an aromatic dianine [125]. Li et al. [126] used the modified HETCOR pulse sequence to study d5-PS/PPO, d3-PS/PPO and d3-PS/d5-PS blends. The cross-peak intensities increase with increasing the spin-diffusion period, and the distance between interacting components was determined. Instead of inserting the spin-diffusion period, Takegoshi and Hikichi [127] used the conventional CP sequence for a mixing sequence to study an interpolymer interaction of PMA/PVPh. They found that with a CP contact time of 0.2 ms, no appreciable interpolymer cross-peaks appear, but with a CP time of 1 ms, the interpolymer cross-peak between the aromatic protons of PVPh and the carbonyl carbon of PMA appears. 

Poly(4-vinyl phenol) with PVAc, EVAc, PCL, PPL, PMA, PEA, PBA, The amount of free and bonded C=0 vibrations were determined fort the PVPh/hydrogen bonding polymer blends, using a curve fitting procedure Coleman et al., 1989... 

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