Strengthening Process by Electron Beam to Carbon Fiber for Impact Strength Enhancement of Interlayered Thermoplastic-Polypropylene Carbon Fiber Composite

Abstract

Strong adhesion between recyclable thermoplastic (TP) polymer and carbon fiber (CF) has always been highly sought after. Therefore, for an interlayered CF reinforced TP polypropylene (CFRTPP) composite composed of 3 sized CF plies, alternating between 4 PP sheets, designated [PP]4[CF]3, a process of activating CF plies directly on both sides with homogeneous low energy electron beam irradiation (EBI) under N2 gas, prior to lamination assembly and hot press of 4.0 MPa at 493 K for 3 min was carried out. Experimental results showed EBI dose of 43.2, 129, or 216 kGy significantly raised Charpy impact values, auc at all fracture probabilities, Pf. The 129 kGy dose appeared to be at or near optimum increasing auc 103%, 83%, and 65% at low-, median-, and high-Pf = 0.07, 0.50, and 0.93; while raising statistically lowest impact value, as at Pf = 0 calculated by 3-dimensional Weibull equation about 110%, indicating increased safety and reliability. It is assumed dangling bonds generated by the EBI rapidly form covalent bonds CF:C:O:C:PP and CF:C:C:PP at the interface, along with cross-linking in the PP near the CF. This is by charge transfer from CF to PP.

A New Strengthening Process for Carbon-Fiber-Reinforced Thermoplastic Polyphenylene Sulfide (CFRTP-PPS) Interlayered Composite by Electron Beam Irradiation to PPS Prior to Lamination Assembly and Hot Press

“…Figure 3 shows a schematic of the electron curtain processor. HLEBI setup and parameters are described in detail in [ 38 ].…”

“…Applying HLEBI to sample surfaces has been shown to improve fracture toughness of several CF and glass fiber (GF) FRPs [ 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. Moreover, HLEBI has been utilized to directly activate CF [ 24 , 36 , 37 , 38 , 39 , 40 , 41 ] and GF [ 42 ] to increase mechanical properties of FRP. HLEBI is reported to strengthen glasses [ 43 , 44 ] and BMCs [ 33 ] by generating dangling bonds at low bond dissociation energy (BDE) sites with repulsive force between electrons, creating internal compressive forces.…”

Increasing Bending Strength of Polycarbonate Reinforced by Carbon Fiber Irradiated by Electron Beam

“…During treatment, temperature was controlled so not to exceed 323 K. Given the reported CF density of 1760 kgm −3 , the penetration depth, D th , was 123 µm into both sides of each 230 µm thick CF ply, penetrating throughout the ply's thickness [42]. A detailed description and parameters of the HLEBI treatments employed can be found in [43].…”