Low viscosity and high toughness epoxy resin modified by in situ radical polymerization method for improving mechanical properties of carbon fiber reinforced plastics

Abstract

In situ radical polymerization method, which is a method for toughening thermosetting resins by modifier polymers radically generated in the curing system of the resins, was applied to epoxy resin for the matrix of carbon fiber reinforced plastic (CFRP) to achieve both high fracture toughness of the cured resin and low viscosity of the resin composition. Benzyl methacrylate (BzMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) were selected as the modifier monomers, and the resulting cured epoxy resin having co-continuous phase separation with the polymerized modifier at a nanometer level showed 2.1 times higher fracture toughness (K IC) than the unmodified cured resin. The modified epoxy resin system was then successfully applied to the fabrication of CFRP by resin transfer molding (RTM) due to its low viscosity in the uncured state. The resultant CFRP system showed 30% increase of the interlaminar fracture toughness (G IC) from the unmodified system.

Preparation, Properties and Mechanisms of Carbon Fiber/Polymer Composites for Thermal Management Applications

“…Adding a certain amount of the modifier to the polymer matrix could reduce the viscosity of the polymer matrix to improve the impregnation efficiency, which is favorable to improve the mechanical properties and thermal conductivity of the composite material. Jun et al [ 65 ] selected polyethylene glycol methyl methacrylate (PEGMEMA) and benzyl methacrylate (BZMA) as modifier monomers to add to the diglycidyl ether of bisphenol-A (DGEBA) resin. When the contents of PEGMEMA and BZMA modifiers were 16.7 and 3.3 wt%, respectively, the fracture toughness of the CF composite material reached its highest value, which indicates that with the addition of the modifier, the binding performance of CF and polymer matrix is enhanced.…”

Insights into the synergistic mechanism of reactive aliphatic soft chains and nano‐silica on toughening epoxy resins with improved mechanical properties and low viscosity

“…However, low viscosity of the epoxy curing mixture is another key factor that directly determining the processing ability of fiber-reinforced epoxy composites, especially for automotive manufacturing methods such as resin transfer molding (RTM), injection molding, and infusion molding. 63 Usually the mixed viscosity should be lower than 1 PaÁs at room temperature for RTM process. 64 The mixed viscosity (before curing) of Pure EP and EP C:Si-m:n (m + n = 4) systems were shown in Figure 7.…”

Temperature effects on structural integrity of fiber‐reinforced polymer matrix composites: A review

“…The development of polymer matrix composites has always been focused on the goals of improving properties, enhancing functions, reducing costs, and facilitating production. In polymer matrix composites, the properties of composites are determined by the matrices . Moreover, resin characteristics not only directly affect the properties of composites but also affect the processing performance.…”