Enhancing interfacial interactions of cocontinuous poly(lactic acid)/polyethylene blends using vinylsilane grafted carbon nanotubes as generic reactive compatibilizers

Abstract

Vinylsilane grafted carbon nanotubes (VCNTs) can act as reactive compatibilizers for cocontinuous poly(lactic acid)/high-density polyethylene (PLA/HDPE) blends, with the aid of organic peroxides initiated radical reactions. The reactively compatibilized PLA/HDPE/VCNTs blend nanocomposites exhibit strong interfacial interactions, as can be reflected by the remarkably increased storage modulus at low frequencies. Due to strong interfacial interactions, the VCNTs act as highly efficient nucleating agents for the PLA component. With 2.0 wt% of VCNTs, the crystallinity of PLA component reaches a value of 33.8% after melt cooling, and thus cold crystallization can no longer be observed upon heating. Thanks to the high crystallinity of the PLA component, the reactively compatibilized blend nanocomposite with 2.0 wt% of VCNTs shows a much higher elastic modulus than those of pristine PLA/HDPE blends and uncompatibilized blend nanocomposites in the temperature range of 60 to 80°C. Moreover, the reactively compatibilized blend nanocomposites exhibit an obvious increase trend in tensile strength with increasing the content of VCNTs, due to stronger interfacial interactions. This work provides a generic strategy for compatibilizing and reinforcing immiscible polymer blend nanocomposites using reactive carbon nanotubes.

Keywords

• polymer composites
• rheology
• interfacial interactions
• thermal properties