The Structure And Properties Of Resin Matrix Composites With High Strength And Light Weight

One of the most important questions for advanced composites, such as aerospace, deep sea buoyancy and wind power generation materials was keeping their light weight and increasing the strength. Hollow glass beads (HGB) with series of excellent properties, such as low density, high strength and good dispersion in resins could be one of effective solutions. In this work, HGB with density less than 1g/cm3 and controllable compression strength were obtained via a self-designed vertical high-temperature molding furnace. Furthermore, soluble rare earth compound possessing double effects ofβ-crystals nucleation and surface modification were adopted to treat the surface of the HGB via a deposition method, and the interfacial compatibility and mechanical properties of polypropylene/hollow glass beads (PP/HGB) composites were improved. In addition, aimed at solving the problem of carbon nanotubes (CNTs) difficultly dispersing in resins, HGB were used as carriers, and CNTs were firstly grafted on the surface of the HGB to be“CNTs beads”and followed mixing with epoxy resin (EP). The experimental results showed that this carrier method could obviously improve the dispersion of the CNTs in EP as well as the properties of the composites.The HGB possessing uniform texture, controllable density with the scope of 0.18～0.78g/cm3 and the maximum compression strength of 85.7MPa were obtained via the sol-gel/furnace method. The hollow structure and morphology of the HGB could be controlled by the weight fraction of foaming agents, firing temperature and time. Furthermore, the density, particle size, wall thickness and resistance to static pressure strength of HGB could be controlled by the size of dry gel powder. In addition, another method for preparing HGB, hollow silica spheres with microporous and mesoporous in the shell were efficiently synthesized by using tetraethoxysilane as the silica resouce, octylamine as the vesicle template, and dilute hydrochloric acid or potassium/sodium salts as the catalyst. The size of the beads with high specific surface area could be controlled by the additive amount of Tween 20 and the intensity of ultrosonic wave. Furthermore, the organic materials were removed and the beads was densified to be HGB when the hollow silica spheres were fired in the vertical high-temperature molding furnace.The experimental results also showed that the complex viscosity (η*), storage (G’) and loss (G’’) modulus of the composites were improved when the HGB were mixed with the PP. Moreover, the interfacial compatibility between the HGB and the PP, tensile and notch impact strength of the PP/HGB composites were improved when the HGB were modified by cerous or yttrium. The optimum weight concentration were 1.2wt% and 0.5wt%, respectively. Furthermore, The formation ofβ-crystals was facilitated by these rare earth compound, the crystal particle size was decreased and homogenized, and the crystallization temperature, enthalpy and crystallinity of the composites were also increased.In N, N-Dimethyl formamide solvent, adopting the carrier method to graft the CNTs on the surface of the HGB had obvious advantages to improve the mechanical and the electrical properties of EP/HGB composites. The amount of the CNTs on the surface of the HGB could be controlled by several parameters such as reaction temperature, time and the weight ratio of the HGB and the CNTs. Then, the structure and the properties of EP/HGB/CNTs ternary composites could be controlled, and the composites with light weight, high strength and better electrical conductivity could be obtained.