Reducing the cost of composite material production is significant for expanding its usage and application in many ways, such as in the fields of aerospace, aviation, ocean industry and so on. To do this, it is important to minimize the production process of the material and to decrease the amount of scraps or any unnecessary particles. The Vacuum Assisted Resin Transfer Molding (VARTM) process, which is known for having many advantages, has become recognized as one of the most low-cost manufacturing model. VARTM process can be divided into three main steps: performing, resin filling and hardening steps. The most important step among all these three steps is the Resin Filling stage, a process when Resin is impregnated into the mat. Mostly, Resin Filling stage is greatly affected by the level of permeability, a characteristic of stiffener due to pneumatic resistant nature in the process. Other factors such as viscosity, technological vacuuming, or even stiffening process itself could also influence the production as well. During Resin Filling stage, Resin tends to spread out in the center first because of capillary phenomenon. In this research, the researchers examined the mechanical property and the pneumatic nature of Resin by dividing the pneumatic movement of the Resin into sections. Based on this result, the researchers found the correlations between the capillary phenomenon and Resin impregnation, and analyzed the movement mechanism in Resin filling stage.
The wide range of applications for composite materials ensures an almost inevitable contact with liquids and vapors, either organic or aqueous, which can affect both the immediate and the long-term performance of the material. The mechanisms of water absorption, the plasticizing effect of absorbed moisture and the lowering of the glass-rubber transition temperature are well known processes which have been widely studied in polymeric materials. To a lesser extent, water absorption has also been studied in composite materials and it has been shown that, in general, the mechanisms of moisture penetration are much more complex than in the case of the unreinforced matrix. Water absorption has been shown to lead to a general reduction in the mechanical properties of composites and this has been attributed, in part, to degradation of the fiber-matrix interfacial bond.