Fabrication,Modification And Performance Research Of Hollow Glass Fiber Reinforced Plastic

Glass fiber reinforced composite materials is one of the most commonly used materials in the field of radomes.Recently,high-performance,low-density,wide-frequency band,and high-permeability materials become the developing trend of radome materials.This puts forward new requirements for the composites with comprehensive performance.Hollow glass fiber composites are expected to be a new generation of radome composites with better performance because of their lower density,higher specific strength/modulus and lower dielectric loss.However,there are few research reports on hollow glass fiber and its composites.In this paper,to investigate the application prospects of hollow glass fiber composite in radome field,the properties of hollow glass fiber itself and the fabrication,modification and performance of hollow glass fiber reinforced plastic are researched.In this paper,commercial hollow glass fiber with the hollowness of 16%,and the internal/external diameter of 4?m/10?m has been choosen as reinforcing material.The monofilament strength and the multifilament strength of the hollow glass fiber were tested.The results show that the tensile strength of the monofilament is in accordance with the Weibull strength distribution model.Compared with the solid glass fiber with outer diameter of 16?m,the monofilament strength and the multifilament strength of the hollow glass fiber is not dominant.The hollow glass fiber and solid glass fiber prepreg were prepared by wet winding process,and the unidirectional glass fiber composite material was fabricated by molding process,and its mechanical properties were tested and analyzed.The results show that the specific modulus and specific compressive strength of hollow glass fiber unidirectional plate are higher than that of solid glass fiber unidirectional plate.Hollow glass fiber and solid glass fiber composite laminates were prepared by vacu?m infusion process,and their mechanical properties were analyzed and evaluated.The results show that the mechanical properties of hollow glass fiber composite(HGFRP)are lower than that of solid glass fiber composite(SGFRP).The interface of HGFRP was found to be weak by scanning electron microscopy(SEM).Therefore,the hollow glass fiber was modified by heat treatment,coupling agent treatment,chemical reagent treatment and combined treatment.It was found that the optimal heat treatment condition of hollow glass fiber was 400~oC/1h,and the best modification method was treatment with coupling agent solution.The tensile,bending and shear property of HGFRP was analyzed.And the results show that the interface strength of the modified composites is improved obviously and the mechanical properties are greatly improved.The tensile strength increases from 165.94MPa to 231.798MPa,which is increased by39.69%.Bending strength increased from 282.63MPa to 328.42MPa,increased by16.20%.Shear strength increased from 38.13MPa to 48.08MPa,increased by 26.09%.The dielectric properties of HGFRP and SGFRP were analyzed by waveguide method.The dielectric properties of glass fiber composites were characterized by dielectric constant?and dielectric loss tan?.The results show that the?of HGFRP were significantly lower than that of SGFRP in both X and Ku frequency bands.In addition,the dielectric loss tan?of HGFRP that are modified by different methods have apparent decrease than of unmodified,indicating that modified HGFRP can guarantee the basic mechanical properties and improve the dielectric properties of materials at the same time.Therefore,HGFRP have more advantages in radome field compared with SGFRP.