Effect of Highly Fibrillated High‐Density Polyethylene Fibers on the Physical and Mechanical Properties of Bisphenol‐A Epoxy Matrix

ABSTRACT

This study systematically investigates the effect of highly fibrillated high‐density polyethylene (HDPE) fibers on a Bisphenol‐A epoxy matrix. These fillers were added in varying dosages of 0.25%, 0.5%, 0.75% and 1% by weight to the Bisphenol‐A epoxy matrix, and the results were compared, wherever possible, to the data for non‐fibrillated HDPE‐reinforced systems. The results exhibited clear concentration‐dependent trends, with matrix viscosity increasing with an increase in the concentration of HDPE fibers. The highest Shore‐D hardness (86) and lap‐shear strength (9 MPa) were both exhibited at 0.75 wt.% of fiber loading, whereas the longest pot life (162 min) was achieved with 0.25 wt.% fiber. Overall, the fibrillated HDPE fibers demonstrated superior reinforcement efficiency compared to their non‐fibrillated counterparts, except for the hydrophobicity. Fourier‐transform infrared spectroscopy (FTIR) confirmed successful incorporation of the fibers into the epoxy matrix. Thermal properties investigated by TGA and DSC revealed improved thermal stability with increasing fiber contents. The contact angle measurements of the composites suggest that their excellent water resistance is due to the hydrophobic properties of HDPE fibers. Additionally, a morphological study conducted using scanning electron microscopy (SEM) confirmed these trends. Furthermore, a morphological study using SEM confirmed the observed trends and revealed interfacial adhesion, reinforcement sites, and fiber agglomeration sites within the epoxy matrix at various concentrations.