|
Because of its unique structure of carbon nanotubes and transmission characteristics, and has excellent mechanical, electrical, thermal, optical and electromagnetic and other special properties, is used as the polymer matrix material of special enhancements researchers already received widespread public attention. Nanocomposites can greatly enhance the performance of the polymer material, making it more widely. However, carbon nanotubes in the polymer matrix tangles reunion serious and dispersion and interfacial adhesion is poor, which severely restricted the field of carbon nanotubes in the polymer matrix applications. Thermosetting epoxy resin is a common, widely used in industry. Reinforced epoxy with carbon nanotubes, carbon nanotubes can be prepared by high-performance / epoxy composite materials, so that the broader application of epoxy resin. In order to solve the carbon nanotube / epoxy composite fundamental problems existing in the process, thereby producing high-performance composite materials, the content of this research work is divided into three parts, mainly from the carbon nanotubes in an epoxy resin matrix dispersion and interfacial bonding perspective to study epoxy composites with carbon nanotubes Preparation and characterization, through the composite microstructure, thermal properties, electrical properties and mechanical properties characterization, analysis of the modified carbon nanotubes in the ring The mechanism of epoxy resin. In the first part of the research, the main surface of the carbon nanotube surface modification hydroxylation. After purification of carbon nanotubes in dilute nitric acid, with mixed acid, strong alkali, concentrated sulfuric acid / hydrogen peroxide and Fenton reagent reagent mixture of carbon nanotubes, the introduction of hydroxyl groups on its surface, and through glycidoxypropyltrimethoxy silane coupling agent (KH560) modified . Using SEM, FTIR, TGA and other methods were characterized. The results showed that the purified carbon nanotubes on the surface of amorphous carbon and other impurities are removed and the catalyst, the use of a relatively mild reaction conditions, dilute nitric acid purification effect of the damage on the surface of carbon nanotubes is small, and not introduced carboxyl and hydroxyl groups; four methods, Fenton reagent is a carbon nanotube surface hydroxylation is the best way; by Fenton reagent treatment, the introduction of a large number of carbon nanotubes on the surface hydroxyl groups, and further with a coupling agent (KH560 ) on its surface modified epoxy group introduced; silane modified Fenton reagent treated carbon nanotubes dispersed in acetone and the best stability and surface loss rate 8.11%; raw carbon nanotubes and other reagents change the surface of carbon nanotubes without introducing hydroxyl groups and further with a silane coupling agent (KH560) modified dispersion and stability in acetone and carbon nanotube surface does not improve weight loss rate is very low. In the second part of the research, the main study, four coupling agent modified hydroxylated carbon nanotubes and epoxy composites. In order to improve the dispersibility of carbon nanotubes, and to obtain different interface characteristics, respectively, a silane coupling agent KH550, KH560, KH570 NDZ201 titanate coupling agent, and the hydroxylated surface modified carbon nanotubes, using (ultrasonic speed stirring) dispersion - Exhaust - casting - curing different types of carbon nanotubes prepared / epoxy composite effects of different coupling agents modified CNTs composite microstructure, thermal properties, electrical properties and mechanical properties. The experimental results show that when the carbon nanotubes and a silane coupling agent KH560 mass ratio of 1:1, the silane coupling agent KH560 treated carbon nanotubes / epoxy composite thermal properties, electrical properties and mechanical properties of the best and the mainly KH560 silane coupling agent surface-modified carbon nanotubes of carbon nanotubes having an epoxy group in the epoxy resin to improve the dispersibility and interfacial properties; when the carbon content is 0.25%, the composite material The impact strength, flexural strength, flexural modulus and fracture toughness of the pure epoxy increased by 108%, 32.8%, 8.7% and 20%; comparison, the other coupling agent nanocarbon tube / epoxy composites are poor. In the third part of the research, the main study polyfunctional glycidyl acrylate derivatives (GMA) graft polymerization walled Carbon Nanotubes and epoxy composites. Studied three different grafting rate GMA modified carbon nanotubes in an epoxy resin matrix composite material dispersion and its glass transition temperature (Tg), electrical properties, mechanical properties, and also studied the GMA changed and other methods of carbon nanotubes modified when changing the content of the EP nanotube composite electrical properties and mechanical properties. The results showed that, GMA and the mass ratio of 15:1 CNTs treated CNTs highest graft ratio, in acetone dispersion stability and best; GMA coupling agent KH570 modified CNTs Modified than the glass transition temperature of the EP (Tg) increased more significantly, the grafting rate of 30.61% of the GMA modified CNTs that works best; graft rate of 5.12% of GMA modified CNTs / EP composite conductivity best; GMA modified CNTs / EP The dielectric properties of composite materials has changed greatly over EP and the more primitive system of CNTs corresponding dielectric constant and dielectric loss are ten times lower; GMA modified CNTs composite toughening effect on the obvious, GMA and when the mass ratio of 15:1 CNTs treated CNTs / EP composite best mechanical properties, impact strength, flexural strength, flexural modulus and fracture toughness of the various pure EP increased by 90%, 30%, 10 % and 20%.
|