Combined effect of montmorillonite Cloisite 30B and graphene nanoplatelets on high-density polyethylene matrix under high strain rate dynamic compression

Laminated polymer composites are widely used in ballistic barriers where polyethylene can be applied. The mechanical properties of polymers can be improved with the addition of nanofillers. Therefore, this work evaluates the effect of the combination of montmorillonite Cloisite 30B (OMt) and graphene (Gr) on the dynamics compression properties obtained from a split-Hopkinson pressure bar (SHPB) test for nanostructured maleinized high-density polyethylene (HDPE). The nanofillers are incorporated into the polymeric matrix in its molten state, and their dispersion is evaluated through x-ray diffraction and transmission electron microscopy analyses. Thermal analysis, including differential scanning calorimetry and thermogravimetric analysis are performed. Additionally, the viscoelastic behavior of the materials is studied from the results of storage and loss modulus obtained by dynamic-mechanical analysis. Under the SHPB test conditions, it is possible to evaluate the material stress-strain curve, identifying its yield point, compressive strength, and deformations to calculate the elastic stiffness and toughness of the material. The nanocomposite with 3% OMt and 0.75% Gr (wt.%) shows the highest average compressive strength and toughness values. Furthermore, this sample shows similar T-peak temperature, improved crystallinity index, storage, and loss modulus, with similar glass transition temperature compared to the HDPE sample.