The effects of chemical grafting 1,6-hexanediol diglycidyl ether on the interfacial adhesion between continuous basalt fibers and epoxy resin as well as the tensile strength of composites

Abstract

The poor interfacial adhesion between continuous basalt fibers (CBFs) and epoxy resin (EP) is enhanced via chemical grafting aliphatic chains on CBFs surface. 3-aminopropyltriethoxysilane (KH550) play a role of bridge to link 1,6-hexanediol diglycidyl ether (HDE) chains and CBFs surface. Subsequently, CBFs-g-KH550-g-HDE/EP composites are fabricated from laminating process. The existence of HDE chains on CBFs surface not only improve the mutual infiltration between CBFs-g-KH550-g-HDE and EP matrix to reduce the structural defects at interface, but also enhance the interfacial adhesion to promote the effective load transfer between CBFs-g-KH550-g-HDE and EP matrix. Based on these factors, the tensile strength of composite is significantly improved. The reinforcing effect of CBFs-g-KH550-g-HDE is also related with its surface roughness. When sufficient aliphatic chains covered the entire surface of CBFs with a homogeneous thickness (smooth surface), the tensile strength of composite increased by 56 % compared with the neat CBFs/EP counterpart. When limited or excessive molecules are decorated on CBFs surface, the rough surface become structural defects to weaken the reinforcing effects of fibers.