Improving Interlayer Adhesion of Poly(p-phenylene terephthalamide) (PPTA)/Ultra-high-molecular-weight Polyethylene (UHMWPE) Laminates Prepared by Plasma Treatment and Hot Pressing Technique.

Long Zhu,Simona Percec,Fei Ren,Dmitriy A Dikin

doi:10.3390/polym13162600

Abstract

Poly(p-phenylene terephthalamide) (PPTA) is a high-performance polymer that has been utilized in a range of applications. Although PPTA fibers are widely used in various composite materials, laminar structures consisting of PPTA and ultra-high-molecular-weight polyethylene (UHMWPE), are less reported. The difficulty in making such composite structures is in part due to the weakness of the interface formed between these two polymers. In this study, a layered structure was produced from PPTA fabrics and UHMWPE films via hot pressing. To improve the interlayer adhesion, oxygen plasma was used to treat the PPTA and the UHMWPE surfaces prior to lamination. It has been found that while plasma treatment on the UHMWPE surface brought about a moderate increase in interlayer adhesion (up to 14%), significant enhancement was achieved on the samples fabricated with plasma treated PPTA (up to 91%). It has been assumed that both surface roughening and the introduction of functional groups contributed to this improvement.

Highlights

Poly(p-phenylene terephthalamide) (PPTA) is a high-performance polymer with high toughness, high tensile strength, and chemical stability at high temperatures
Laminate samples were fabricated from PPTA fabrics and Ultra-high molecular weight polyethylene (UHMWPE) films by hot pressing method
Oxygen plasma treatment was utilized to enhance the interlamellar adhesion between PPTA fabrics and UHMWPE film

Summary

Introduction

Poly(p-phenylene terephthalamide) (PPTA) is a high-performance polymer with high toughness, high tensile strength, and chemical stability at high temperatures. Hofste et al used chromic acid to chemically oxidize the UHMWPE powder before mixing it with the PPTA fiber [19] They found that the wear resistance and other mechanical properties were improved due to stronger fiber/matrix adhesion. Su et al studied the effect of oxygen plasma treatment on Kevlar® fibers and Kevlar® fiber/bismaleimide composites They found that the oxygen–plasma treatment could change the chemistry and the morphology of the surface, which in turn improved the water resistance, dielectric properties, and interlaminar shear strength (40% higher than that of the untreated) [42]. The epoxy glue (JB weld epoxy) was purchased from JB Weld Company (Sulfur Springs, TX, USA)

Oxygen Plasma Treatment

Characterization of PPTA Fabrics and UHMWPE

Morphologies of PPTA Fabric and UHMWPE Film

Adhesion Properties

Failure Analysis

Conclusions