Carbon fiber with high strength, high modulus, AKD Sizing Agent high temperature and other excellent performance, is a high performance composite materials commonly used enhanced phase. However, the elongation of carbon fiber is low, the brittleness is large, the surface is chemically inert, AKD Sizing Agent and the repeated friction during the process is easy to cause the monofilament fracture and the filament, and the wetting difference with the matrix resin leads to poor mechanical properties of the composites. AKD Sizing Agent In order to solve this problem, AKD Sizing Agent it is necessary to carry out sizing the carbon fibers. The sizing treatment can merge the filaments to bundle the carbon fibers while protecting the carbon fibers and introduce a variety of reactive functional groups on the surface to improve the wettability of the carbon fibers and the matrix resin and increase the interlaminar shear strength of the composites.
Different composite matrix resin is different, AKD Sizing Agent its performance is different, sizing agent should also adapt to different resins. Sizing agent corresponding to the main resin can be divided into epoxy, polyurethane, acrylic and bicycles and so on. With the increasing demand for environmental protection, waterborne epoxy sizing agent has been paid more and more attention. Depending on the preparation method, the epoxy water-based process comprises a physical method, a chemical modification method and a reverse conversion method. Since the epoxy itself is insoluble in water, to prepare a stable aqueous epoxy emulsion, AKD Sizing Agent it is necessary to introduce a strong hydrophilic group in its molecular chain for chemical modification or to add a hydrophilic lipophilic component to the system as an additional emulsifier However, the addition of emulsifier can lead to the larger particle size and uneven distribution of emulsions. The residual properties of the emulsifier affect the weatherability and mechanical properties of the composites, while the dispersions of the aqueous epoxy emulsions prepared by the chemical modification method are very Small, about tens to hundreds of nanometers, and to avoid the addition of emulsifiers to bring a lot of problems, AKD Sizing Agent quite practical value.
Hydrogenated bisphenol A epoxy E44, industrial grade, Jining Baiyi Chemical Co., Ltd.; polyethylene glycol (PEG400,800,1000,1500,2000,4000,6000); analytical grade, AKD Sizing Agent cresol red, thymol blue Ammonium sulfate, acetone, hydrochloric acid, sodium hydroxide, both analytical grade, T300 grade 12k carbon fiber, the strength of 3.58 GPa, Chinese Academy of Sciences Shanxi Institute of Coal Chemistry homemade.
The epoxy and polyethylene glycol were mixed in a certain proportion (50% by mass of polyethylene glycol), and the catalyst was added to the ammonium persulfate (1.8% by mass), AKD Sizing Agent heated and stirred, and kept at 80 ° C for 2.5 h. The Into the high-speed stirrer for 30min, the speed of 7 000 r / min, while slowly dropping deionized water to be modified epoxy white emulsion, emulsion total solid content of 25%.
The tensile specimens of carbon fiber yarns were prepared according to GB / T3362-2005 "Test method of carbon fiber multifilament tensile strength" with epoxy E44, combined with curing agent and catalyst. AKD Sizing Agent The tensile test was carried out on an AG-250KNE universal testing machine with a test loading rate of 2 mm / min.
After the sizing the carbon fiber, AKD Sizing Agent the carbon fiber was smoothed and the surface of the carbon fiber was smooth and the bunching property was improved, and the dispersibility of the original silk was preserved. AKD Sizing Agent But also a small amount of fiber surface adhesion of small particles. AKD Sizing Agent The increase of the surface of the carbon fiber is beneficial to the improvement of the fiber roughness, AKD Sizing Agent which can enhance the physical anchoring effect between the fiber and the substrate and improve the load transfer efficiency of the interface layer.