Original Article Enhanced interfacial adhesion of UHMWPE fibers by alkali treatment and its behavior to PI resins Gang Tang 1,2 , Xiong Hu 1 , Tianhao Tang 1 , Christophe Claramunt 1 and Chengliang Liu 2 Abstract The effect of alkali treatment on the UHMWPE fiber and interface of its composites was evaluated by atomic force microscopy, X-ray photoelectron spectroscopy, single-fiber tensile strength analysis, and dynamic contact angle analysis. The objective of this work is to improve the interlaminar shear strength of the composites by mixing the PI resin and modifying the UHMWPE fibers. Surface analysis showed that after treatment, the surface roughness and the wetting ability of UHMWPE fiber were increased. Results indicated that the alkali treatment plays a more important role in improving the surface property and interfacial adhesion of UHMWPE fibers’ composites. Keywords Alkali treatment, PI, UHMWPE fiber, mechanical properties, AFM Introduction The mechanical performance of advanced composites depends to a large extent on whether the mechanical stresses can be efficiently transferred from the matrix to the reinforcing fibers. 1,2 It is established that the interfacial properties of composites are mainly determined by the reactivity and compatibility between the matrix composition and the surface properties of reinforcing fiber. 3–6 UHMWPE fiber and its composites have been widely used in a variety of areas, such as the aerospace industry, automobile applications, and sporting goods for its high 1 Logistics Engineering College, Shanghai Maritime University, Shanghai, China 2 School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, China Corresponding author: Chengliang Liu, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. Email: lishibindv@163.com Journal of Thermoplastic Composite Materials 1–10 ª The Author(s) 2017 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0892705717743296 journals.sagepub.com/home/jtc