Rapid Vacuum Infusion and Curing of Epoxy Composites with a Rubber-Cushioned Mold Design

et al. 2020

Vacuum-Assisted Resin Infusion (VARI) and Resin Transfer Molding (RTM) techniques are the most common techniques for the manufacturing of polymeric composite laminates. The VARI technique has a lot of advantages such as low cost, free voids laminates and the ability to produce complex shapes. However, it has some drawbacks such as poor surface finish and temperature instabilities. On the contrary, the RTM technique can withstand high temperature, producing a good surface finish and complex shape laminates. However, it has a high tooling cost and poor quality laminates due to void contents. In this study, a new technique integrated both VARI and RTM techniques is developed to minimize their drawbacks. This technique involves using a semitransparent composite plate instead of a vacuum bag in the VARI technique. This semitransparent plate takes the inverse shape of the composite laminate similar to the RTM tooling. However, this plate has a low cost compared with RTM tooling and allows monitoring of the resin flow during the infusion process. To validate the integrated technique, the mechanical properties of composite laminates are compared with that produced by hand layup technique (HLT). Moreover, the influence of incorporation of 0.25 wt. % and 0.5 wt. % of titanium dioxide (TiO2) nanoparticle into woven and chopped fiber/epoxy composite laminates was demonstrated. The results indicated that the laminates fabricated by the integrated VARI method showed higher mechanical properties than those produced by the hand-layup technique. Moreover, glass fiber/epoxy filled with 0.25 wt. % of TiO2 nanoparticles gives high mechanical properties.

Section: Smentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Integrated vacuum assisted resin infusion and resin transfer molding technique for manufacturing of nano-filled glass fiber reinforced epoxy composite

Agwa

et al. 2020

“…The neat and nanofilled composite laminates were produced by the vacuum resin infusion process. This process consists of three stages: pre-infusion, infusion, and post-infusion [32,33]. Wax was applied to the mold in the pre-infusion stage subsequently, the mold was left to dry.…”

Section: Experimental Workmentioning

confidence: 99%

Hardness, wear behavior and processing time of diluent and non-diluent nanocomposite laminates manufactured by vacuum infusion technique

Agwa

et al. 2020

The manufacturing of nanocomposites using the Vacuum Resin Infusion (VRI) technique can be considered a challenging task. The reason for this challenge is the high viscosity of the nanofilled resin. For large composite laminates, the nanofilled resin may be cured before complete mold filling, and thus can be considered as a waste of money. In this study, different weight fractions of TiO2 nanoparticles (0.25 wt. % and 0.5 wt. %) were added to epoxy resin. Also, different weight fractions of ethanol (0.5 wt. % and 1 wt. %) were added to both unfilled and nanofilled epoxy. The processing time, hardness, and wear behavior of the composite laminates were investigated. It was found that the addition of TiO2 nanoparticles improved the hardness and wear behavior of composite laminates but the processing time was high. Also, results showed that adding a small amount of ethanol (0.5 wt. %) and 0.25 wt. % of TiO2 nanoparticles to epoxy reinforced with chopped/woven glass fiber not only reduced the processing time but also improved the hardness and wear resistance as compared to neat composite laminates. Moreover, adding 0.5 wt. % of ethanol and 0.25 wt. % of TiO2 nanoparticles to woven E-glass/epoxy (WN0.25E0.5) gives hardness and wear resistance close to that obtained with woven E-glass/epoxy filled with 0.5 wt. % of TiO2 nanoparticles (WN0.5). It is economical to manufacture WN0.25E0.5 rather than WN0.5 as the cost and processing time of WN0.25E0.5 is lower than WN0.5.

“…The VRI process consists of three stages: pre-infusion, infusion, and post-infusion [43]. In the pre-infusion stage, the wax was applied to the surface of the mold, then the mold was left to dry.…”

Section: Experimental Workmentioning

confidence: 99%

Effect of ethanol on the mold filling-time and mechanical properties of woven glass fiber reinforced epoxy filled with TiO₂nanoparticles

Megahed

et al. 2020

Vacuum resin infusion (VRI) is a promising technique for manufacturing complicated structural laminates. This high viscosity of nanofilled resin increases the filling time and leads to an incomplete mold filling. The mold filling time can be reduced either by making the fiber dimensions smaller than the mold (gaps around the fibers) or by adding ethanol to nanofilled epoxy. However, ethanol addition influences the mechanical properties of composite laminates. In this study, different amounts of ethanol (0.5 wt. % and 1 wt. %) were used as a diluent to both neat epoxy and epoxy filled with (0.25 wt. %) of titanium dioxide (TiO2) nanoparticles. From results, it was found that ethanol addition saves the time for neat and nanofilled epoxy by 47.1% and 24.1%, respectively. It was found that adding 0.5 wt. % of ethanol to 0.25wt. % of TiO2 nanoparticles (GT0.25E0.5) enhances the tensile and flexural strength by 30.8% and 55.9%, respectively compared with neat specimens. Furthermore, the tensile and flexural moduli increased by 62% and 72.3%, respectively. Furthermore, the mold filling time was investigated experimentally and validated numerically using ANSYS FLUENT software. The mold filling time prediction using ANSYS FLUENT can be used to avoid resin gelation before the incomplete mold filling and thus can be considered a cost-effective methodology. The results showed that the gaps around the fibers reduce the time by 178% without affecting the mechanical properties.