Abstract
Free induction decay (FID) signals of macroscopic magnetization M(t) obtained by pulsed NMR have much information on the physical properties of polymeric materials. In our previous studies,the magnetic relaxation spectra of the polymeric materials were determined by the numerical differentiation on the FID signals. In this paper,combined FID signals were calculated using the proton ratio in the SIS/SI/tackifier pressure-sensitive-adhesives (PSAs), based on the FID signal of the each component in the PSAs. The difference between the combined relaxation spectrum calculated from the combined FID signal and the measured relaxation spectrum of the actual PSAs gave the difference spectrum. The difference spectra quantified the interaction among components,such as the effect of the amount of the SI diblock and the tackifiers on the relaxation behaviors. The magnetic relaxation spectrum describes the relaxation behaviors of the protons,i.e., the mobility of the main chain and the side chain of polymers. Therefore,the difference spectrum of SIS/SI/tackifier system suggests the miscibility of the tackifier to the polyisoprene (PI) phase in the SIS/SI. The difference spectra given by the pulsed NMR are an effective method to lead the design of elastomer/tackifier PSAs.
