Three-phase sandwich composite materials are used in shipbuilding, offshore structures, and wind power, and this document outlines the manufacturing process for these materials.

Abstract

The invention relates to vacuum bag technology applied to the fabrication of two-phase and three-phase composite materials, as well as two-phase and three-phase sandwich composites. According to several schemes, the invention proposes a three-phase sandwich composite material produced by vacuum bag technology, in which the material consists of a rigid, porous polyvinyl chloride (PVC) core, preferably with a nominal density between H80 and H250, arranged between three-phase composite layers, preferably two layers. Each three-phase composite layer consists of glass fiber (GF), polyester resin, methyl ethyl ketone peroxide (MEPOXE) curing catalyst, and graphene nanoparticles in appropriate amounts as described in the description.The invention also proposes a process for producing composite materials, preferably the aforementioned three-phase sandwich composite material, using vacuum bag technology, in which nanographene is dispersed into polyester resin, a curing catalyst is added, the resin mixture is impregnated onto the glass fiber reinforcement layers, a PVC core is placed between the three-phase composite skin layers, and the curing process is carried out using vacuum bag technology with a vacuum pressure of -0.06 to -0.08 MPa (-600 mbar to -800 mbar) under ambient conditions of room temperature (25 ± 5)oC and humidity of 65 ± 20%. Tests show that three-phase sandwich composite panels achieve a flexural elastic modulus ≥ 14 GPa, a maximum bending force ≥ 2.4 kN, and a maximum load deflection ≤ 10 mm, demonstrating an improvement in stiffness of > 30% and flexural strength of ≥ 50% compared to two-phase materials manufactured by hand casting. They can be applied in shipbuilding, offshore structures, and wind power.