Abstract: Unsaturated polyester-based composites reinforced with ramie fiber and glass fiber was prepared by Vacuum Assisted Resin Infusion (VARI) process. Different kinds of hybrid composites were studied. It was found that the sandwich structure which glass fiber as shell and ramie fiber as core (GRUP) has better mechanical properties than the sandwich structure which ramie fiber as shell and glass fiber as core (RGUP) in the same hybrid ratio. And, the mechanical properties of the interplay hybrid composite (IPUP) are between the two kinds of composites. Different hybrid ratios under the same sandwich structure were studied. It was found that the content of ramie fiber and the mechanical properties are negatively related. The relationship between the content of ramie fiber and the tensile strength as well as the tensile modulus follows a linear function, while the flexural strength and modulus are complied a cubic curve with the content of ramie fiber.

Key words: hybrid composites, unsaturated polyester, ramie fiber, mechanical property