A study of diffusional behavior of polymer having semiflexible main-chain with long n-alkyl side-chains as associated with structural behavior of the side-chains

Structural and dynamic characterizations of poly(n-octadecyl methacrylate)(PODMA) have been made at -8.2 and 13.6 degrees C below the melting temperature (T-m) of the n-octadecyl side-chain crystallite and at temperatures from 25.8 to 65 degrees C above the T-m of the n-octadecyl side-chain crystallite by C-13 CP-MAS NMR, and have been made at temperatures from 30 to 80 degrees C by C-13 DD-MAS NMR, respectively. Also, the H-1 T(2)s of the n-octadecyl side-chain have been measured as a function of temperature in the temperature range from 20 to 80 degrees C by H-1 spin-echo H-1 NMR, and its dynamic behavior has been studied. Further, diffusional behavior of PODMA chains in the molten state at temperatures above the T-m of the n-octadecyl side-chain crystallite has been elucidated through determination of the diffusion coefficients (Ds) by means of pulsed field-gradient stimulated-echo (PFGStE) H-1 NMR method. The existence of the two kinds of the D-slow component with the order of 10(-11)-10(-10) cm(2) s(-1) as the major component and the D-fast, component with the order of 10(-7) cm(2) s(-1) as the minor component in diffusion process of PODMA chains in the molten state has been shown and further their diffusion behaviors have been discussed. (C) 2010 Elsevier B.V. All rights reserved.