Determination of low-velocity impact properties of polyethylene matrix hybrid composite materials aged in saline environment

In this study, the low-velocity impact behavior of polyethylene (PE) matrix hybrid composites aged in a saline environment was investigated under simulated marine conditions containing 3 wt.% NaCl. Basalt, glass, and carbon fibers were used as reinforcements individually and in hybrid configurations within the PE matrix to fabricate composite plates, which were aged for 0, 1, 2, 3, and 5 months. Following the aging process, axial tensile, three-point bending, and low-velocity impact tests were performed according to ASTM standards. The results revealed a noticeable decline in flexural strength across all composites with increased aging duration. Carbon fiber-reinforced PE composites exhibited the highest resistance to environmental degradation, maintaining a flexural strength of approximately 10 MPa at the end of the 5th month, down from around 17 MPa at the initial state. Glass fiber-reinforced PE composites showed a significant reduction in flexural strength, dropping from about 47 MPa initially to around 17 MPa after 5 months due to moisture absorption and weak interfacial bonding, corresponding to a reduction of over 60%. Basalt fiber-reinforced PE composites demonstrated an initial flexural strength of 28 MPa, which decreased to around 10 MPa by the 5th month, indicating intermediate environmental durability. In low-velocity impact tests, glass-carbon-basalt hybrid composites exhibited an energy absorption of approximately 30 J at the 1st month, which decreased to around 22 J by the 5th month, reflecting a reduction of 27%. The study concluded that hybrid composites provide improved initial mechanical strength, control deformation under aging, delay crack propagation, and enhance energy absorption capacity by combining the advantages of different fiber types. The findings demonstrate that PE matrix hybrid composites are promising candidates for marine and outdoor applications requiring impact resistance under corrosive conditions.