Decorated MCM-41/polyethylene hybrids: Crystalline details and viscoelastic behavior

Polyethylene-based nanocomposites have been prepared by in-situ polymerization of ethylene with mesostructured MCM-41. Different approaches are used to improve interfacial adhesion between components, high density polyethylene (HDPE) matrix and MCM-41. These consist either of the incorporation of UA in the polymer chains by copolymerization in a very small content or of the modification of MCM-41 surface with the system based on undecenoic acid, UA/triisobutylaluminum, TIBA, before polymerization. The materials attained exhibit minimal changes in the crystallinity resulting from first melting process although a slight increase of long spacing at room temperature is seen as MCM-41 is incorporated in the hybrids. Moreover, a confinement effect is noticed and, thus, a delay in the crystallization process of the macrochains within pores and channels is detected. These novel self-reinforced nanocomposites show higher stiffness than other similar hybrids with poorer interfacial adhesion. Accordingly, they exhibit an enhancement in their mechanical performance without changing the final processing temperature since Tm is the same for all of the specimens.