Facile Strategy of Improving Interfacial Strength of Silicone Resin Composites Through Self-Polymerized Polydopamine Followed via the Sol-Gel Growing of Silica Nanoparticles onto Carbon Fiber.

Yawen Zheng,Xiaoyun Wang,Guangshun Wu

doi:10.3390/polym11101639

Abstract

In the present research, to enhance interfacial wettability and adhesion between carbon fibers (CFs) and matrix resin, hydrophilic silica nanoparticles (SiO2) were utilized to graft the surface of CFs. Polydopamine (PDA) as a “bio-glue” was architecturally built between SiO2 and CFs to obtain a strong adhesion strength and homogenous SiO2 distribution onto the surface of CFs. The facile modification strategy was designed by self-polymerization of dopamine followed by the hydrolysis of tetraethoxysilane (TEOS) onto carbon fibers. Surface microstructures and interfacial properties of CFs, before and after modification, were systematically investigated. The tight and homogeneous coverage of SiO2 layers onto the CF surface, with the assistance of a PDA layer by self-polymerization of dopamine, significantly enhanced fiber surface roughness and wettability, resulting in an obvious improvement of mechanical interlocking and interfacial interactions between CFs and matrix resin. The interlaminar shear strength (ILSS) and the interfacial shear strength (IFSS) of CF/PDA/SiO2 reinforced composites exhibited 57.28% and 41.84% enhancements compared with those of untreated composites. In addition, impact strength and the hydrothermal aging resistance of the resulting composites showed great improvements after modification. The possible reinforcing mechanisms during the modification process have been discussed. This novel strategy of developed SiO2-modified CFs has interesting potential for interfacial improvements for advanced polymer composites.

Highlights

Carbon fiber (CF) reinforced polymer composites with strong strength, light weight, and environmental stability have been widely used as structural materials in aerospace, automotive, and defense industries [1,2,3,4,5]
The mechanical properties of composites mainly depend on the interface between fibers and the matrix [8,9], and interfacial properties are strongly dependent on time, temperature, and fiber orientation
We reported a mild and effective method to construct a multifunctional SiO2 layer on a fiber surface with the aid of a PDA coating to simultaneously improve interfacial strength and environmental stability of composites

Summary

Introduction

Carbon fiber (CF) reinforced polymer composites with strong strength, light weight, and environmental stability have been widely used as structural materials in aerospace, automotive, and defense industries [1,2,3,4,5]. The lack of polar groups and the smooth graphitic fiber surface result in a poor-quality interface between CFs and matrix resin [6,7], limiting wide-ranging application of the composites. Zhandarov et al [10] reported a valuable strategy for estimating local fiber/matrix interfacial strength parameters from micro-bond test data. Almeida Jr. et al [11] studied the effects of fiber orientation on interlaminar and in-plane shear properties of glass fiber/epoxy composites using four different shear test methods; they investigated the interfacial and creep characteristics of carbon fiber-reinforced epoxy laminates with different fiber orientations [12]. There are several mechanisms for fiber-matrix bonding, like chemical bonding, mechanical interlocking, physical adsorption, and Polymers 2019, 11, 1639; doi:10.3390/polym11101639 www.mdpi.com/journal/polymers

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