Blend compatibility study by solid-state C-13 nuclear magnetic resonance

The application of proton spin-lattice relaxation time in the rotating fram e and carbon-13 cross-polarization/magic-angle spinning to investigate the compatibility of a polymeric blend formed by high-density polyethylene (HDP E) and a synthetic petroleum resin of low molecular weight showed that this system presents a range of compatibility varying up to 40% (w/w) of the pe troleum resin. The blends showed a shift of the NMR lines to short contact time-i.e., a rigid region. The 60/40 blend clearly displays the presence of domains of distinct mobility: one rigid (short contact time) and the other flexible (long contact time), indicating phase separation. Thus, besides t he crystalline phase of HDPE, the blends show two amorphous phases: one ric h in the polyolefin and the other rich in the low-molecular-weight componen t. (C) 2000 Elsevier Science Ltd. All rights reserved.