Basalt Fibres/Polystyrene Interfacial Adhesion Through Modification of Basalt Fibres by Block Copolymers

The novel macromolecular copolymers of polystyrene-b-poly(2-hydroxyethyl acrylate) (PS-PHEA) and polystyrene-b-poly(2-hydroxyethyl acrylate)-b-poly(ã-methacryloxypropyltrimethoxysilane) (PS-PHEA-PMPS) were synthesized as macromolecular coupling agents via atom transfer radical polymerization (ATRP). The synthetic products were characterized by gel permeation chromatography (GPC) and Fourier transform infrared spectroscopy (FTIR). The polystyrene (PS) block was selected to entangle with homopolymer matrix and form strong interactions with the matrix due to its compatibility potential with the resins. The poly(2-hydroxyethyl acrylate) (PHEA) block is acted as a flexible interlayer and supports some active groups to react with fibres and introduce functional groups. The block poly(gama-methacryl- oxypropyltrimethoxysilane) (PMPS) provides silicon hydroxyl to react with fibres. Basalt fibres (BF) were modified by a commercial silane coupling agent and macromolecular coupling agents, respectively, to improve the poor interfacial compatibility between the fibres and polystyrene. The FTIR confirmed the grafting of the coupling agent on the fibre. The interaction property of fibres and polystyrene was analyzed by the micro- droplet test. The interfacial shear strength (IFSS) values verified that the interaction between the fibre and polystyrene modified with the macromolecular coupling agent was much stronger than that with a normal silane as coupling agent. The di-block copolymer modified composites showed the best improvement in interfacial adhesion. The fibres were treated with 5% PS-b-PHEA solution and reacted at 120°C for 24 h which were considered as an optimal condition for the BF/PS system. The fracture surfaces of the composites before and after treatment were also observed using scanning electron microscopy (SEM). The results proved that the di-block PS-b-PHEA can be used as a good coupling agent for the fibre and polymer composites.