Anping Huang

Accordion-like graphene by a facile and green synthesis method reinforcing polyolefin nanocomposites

Herein, accordion-like graphene with a large specific surface area, efficient reduction degree and designed functional groups was successfully synthesized via thermal expansion exfoliation of alkylated graphite oxide at relatively low temperature (below 170 °C) without any auxiliary equipment. This functional graphene (M-LTRGO) displayed an improved compatibility and interfacial interaction with polyolefin matrix. The graphene-reinforced polyolefin (including polypropylene and polyethylene) nanocomposites exhibited better mechanical strength and thermal stability than the neat and parallel graphene-reinforced polyolefin nanocomposites. The tensile breaking strength of random polypropylene (PPR) and linear low-density polyethylene (LLDPE) increased by 42.77% and 58.59%, respectively, after their incorporation at a loading amount of 0.5 wt%. Into M-LTRGO that is much more stronger than other graphene counterparts obtained via double screw melting compounding. This method provides a new route for the large-scale and green production of functional graphene, endowing the nanocomposites with various functional properties and enhanced mechanical performance, and may have great potential applications in structural engineering plastic and biomedical, soft protection, special packaging, and biotechnological areas.

Preparation of Ultrahigh Molecular Weight Polyethylene/Graphene Nanocomposite In situ Polymerization via Spherical and Sandwich Structure Graphene/Sio 2 Support

Reduced graphene oxide/SiO2 (RGO/SiO2) serving as a novel spherical support for Ziegler-Natta (Z-N) catalyst is reported. The surface and interior of the support has a porous architecture formed by RGO/SiO2 sandwich structure. The sandwich structure is like a brick wall coated with a graphene layer of concreted as skeleton which could withstand external pressures and endow the structure with higher support stabilities. After loading the Z-N catalyst, the active components anchor on the surface and internal pores of the supports. When the ethylene molecules meet the active centers, the molecular chains grow from the surface and internal catalytic sites in a regular and well-organized way. And the process of the nascent molecular chains filled in the sandwich structure polymerization could ensure the graphene disperse uniformly in the polymer matrix. Compared with traditional methods, the porous spherical graphene support of this strategy has far more advantages and could maintain an intrinsic graphene performance in the nanocomposites.