Electrostantic Assembled Glass Fiber/Multiwall Carbon Nanotubes Hybrids Reinforced Polymer Composites

Glass fiber reinforced polymer composites (GFRP) have high strength, chemical resistance, recyclable properties etc., which are widely used in aerospace, automotive, electrical and electronic industries. With the further development of GF-reinforced polymer composites, the needs for specific properties are increasing and GFRP can't meet the demand. Combined glass fiber with carbon nanotubes to construct innovative reinforcement is of great significance on further enhancement and functionality of glass fiber.In this research, multi-wall carbon nanotubes (MWCNTs) network was adsorbed on the surface of GF by the electrostatic attraction between opposite charges, we succeeded in yielding the hierarchical structure reinforcement (GF-MWCNTs). The composites with GF-MWCNTs are prepared by melt compounding and compression molding. The surface of GF-MWCNTs and fractured surface of GF reinforced composites were observed by the scanning electron microscopy. The effect of the synthesizing conditions of GF-MWCNTs on the interfacial adhesion between the glass fiber and the matrix, the mechanical, electrical conductivity was investigated.1. GF-MWCNTs hierarchical structures were created by electrostatic adsorption method. The influence of different kinds of MWCNTs, pH value, and the MWCNTs concentration on the morphology of GF-MWCNTs was studied. As a result, at pH= 3 and CmwcNTs= 2g/L, the longer and flexible MWCNTs was benefit for adsorption on the surface of the GF and forming a uniform and dense coating.The tensile strength of GF-MWCNTs reinforced composite increased 13%～15% compared to the based composite with GF, which resulted from the interface enhancement effect due to the presence of the MWCNTs. Meanwhile, the DMA (Dynamic Thermomechanical Analysis) results showed that the glass transition temperature of GF-MWCNTs reinforced PA6 composite increased from 63℃to 66℃.The results showed that with 1wt% CNTs, the volume resistivity of GF-MWCNTs reinforced composite was lower than that of the pure GF reinforced composite by four orders of magnitude, which reaches 4.9 x 109Ω·cm and is an ideal anti-static material.2. A continuous immersion tank was designed. By controlling the drawing process LGF-MWCNTs reinforcements were continuously produced through the immersion tank filled with MWCNTs suspension. The PA66 composites reinforced with LGF-MWCNTs and MWCNTs masterbatch were prepared by melt compounding on twin-extruder. The results showed that the surface of LGF was uniformly covered with MWCNTs within a short time. The incorporation of LGF-MWCNTs into PA66/CNTs (1 wt%) composite resulted in an improvement of the electrical conductivity by five orders of magnitude.3. The multilayered structures on the surfaces of the GFC, which consist of well-dispersed MWCNTs, are based on sequential adsorption of nanometer-thick monolayers of negatively charged MWCNTs and positively charged Poly(diallyldimethylammonium chloride) (PDDA) by electrostatic layer-by-layer (LBL) assembly method. The resulting [GFC/PDDA-MWCNTs]n reinforcements were infiltrated with epoxy resin by compression molding. The presence of MWCNTs at the interface between fiber and epoxy effectively improved the interfacial adhesion and resulted in an improvement of the interlaminar shear strength by 18%～37%. Meanwhile, the surface resistance of Epoxy/[GFC/PDDA-MWCNTs]n composites dropped to～105Ω, which enhanced the electrical conductivity of the composite greatly.