Grafting Halloysite Nanotubes with Amino or Carboxyl Groups onto Carbon Fiber Surface for Excellent Interfacial Properties of Silicone Resin Composites.

Xiandong Zhang,Guangshun Wu

doi:10.3390/polym10101171

Abstract

The quality of interphase in carbon fibers (CFs) composites makes a key contribution to overall performance of composites. Here, we achieved for the first time the chemical grafting of halloysite nanotubes (HNTs) with amino or carboxyl groups onto the CFs surface aiming to increase composites interfacial strength. HNTs were grafted using 3-aminopropyltriethoxysilane (APS) followed by succinic anhydride treatment, and HNTs with amino groups (HNT–NH2) or carboxyl groups (HNT–COOH) were separately introduced into the interphase of composites. Functional groups of HNTs and fiber surface structures were characterized, which confirmed the modification success. The wettability between the modified CFs and resin have been enhanced obviously based on the improved fiber polarity and enhanced surface roughness by the introduced two functionalized HNTs with the uniform distributions onto fiber surface. Moreover, interfacial properties and anti-hydrothermal aging behaviors of modified methylphenylsilicone resin (MPSR) composites were improved significantly, especially for HNT–COOH grafting. In addition, the interfacial reinforcement mechanisms for untreated and modified CF composites are discussed and compared.

Highlights

Carbon fibers (CFs) have become one of the ideal reinforcements for matrix resin composites because of their strong specific strength, outstanding chemical resistance and superior environmental stability [1,2,3]
For halloysite nanotubes (HNTs)–COOH, a significant band corresponding to the vibrations of carboxylic acids and secondary amides has been observed, and the peak is broad, while the peak intensity is fairly weak owing to few carboxylic acid and secondary amide groups and the existing hydrogen bonding interactions
The above Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) results confirm that APS and succinic anhydride have been successfully grafted onto HNTs surface

Summary

Introduction

Carbon fibers (CFs) have become one of the ideal reinforcements for matrix resin composites because of their strong specific strength, outstanding chemical resistance and superior environmental stability [1,2,3]. Various surface treatment methods have been proposed for changing the CFs surface from chemical inert to active with the aim to improve the quality of interface [8,9,10,11,12]. Many researchers have made considerable efforts to graft the surface of CFs with various active nanoparticles to change interfacial microstructure and properties of composites [13,14,15,16].

Methods

Results

Conclusion