Thermostimulative Shape Memory Effect of Linear Low-Density Polyethylene/Polypropylene (LLDPE/PP) Blends Compatibilized by Crosslinked LLDPE/PP Blend (LLDPE-PP)

A novel linear low-density polyethylene (LLDPE)/polypropylene (PP) thermostimulative shape memory blends were prepared by melt blending with moderate crosslinked LLDPE/PP blend (LLDPE-PP) as compatibilizer. In this shape memory polymer (SMP) blends, dispersed PP acted as fixed phase whereas continuous LLDPE phase acted as reversible or switch phase. LLDPE-PP improved the compatibility of LLDPE/PP blends as shown in scanning electron microscopic photos. Dynamic mechanical analysis test showed that the melt strengths of the blends were enhanced with increasing LLDPE-PP content. A shape memory mechanism for this type of SMP system was then concluded. It was found that when the blend ratio of LLDPE/PP/LLDPE-PP was 87/13/6, the blend exhibited the best shape memory effect at stretch ratio of 80%, stretch rate of 25 mm/min, and recovery temperature of 135 degrees C. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 2512-2519, 2011