Enhanced Tensile Strength of Titanium/Polycarbonate Joint Connected by Electron Beam Activated Cross-Weave Carbon Fiber Cloth Insert

Abstract

A new titanium (Ti)/polycarbonate (PC) joint [Ti/EBCF/PC] internally connected by homogeneous low potential electron beam irradiation (HLEBI) activated cross-weave carbon ber (6 μm in diameter) cloth insert taking advantage of broad CF surface area had been developed. Applying HLEBI dose in the range of 0.043 to 0.43 MGy to the bare CF half-length prior to dipping in the thermoplastic PC molten resin enhanced ultimate tensile strength (σ b) of Ti/EBCF/PC over that without HLEBI [Ti/CF/PC]. The 0.30 MGy dose appeared to be near the optimum resulting in σ b of 20.7 MPa, an increase of 3.0, 3.9 and 21.1 times higher than that of Ti/CF/PC, with glue only [Ti/Glue/PC], and with spontaneous adhesion without glue [Ti/PC], at 7.00, 5.30, and 0.98 MPa, respectively. Moreover, regardless of HLEBI treatment, introduction of the CF insert into the joint prevented abrupt brittle fracture compared to the Ti/PC joint. The corrected ultimate tensile strength (c σ b) de ned as that of the 60 vol% CF-containing PC cross section portion calculated by rule of mixtures was also raised by the 0.30 MGy HLEBI to c σ b = 195 MPa (Ti/EBCF/CFRPC); 6.89 and 31.7 times higher than that of Ti/CF/CFRPC and Ti/PC at 28.3 MPa and 6.16 MPa, respectively. The HLEBI probably enhanced the ability to adhere the CFs to dif cult to adhere thermoplastic PC to generate the tremendously large friction force, with the aim of raising the safety level of lightweight material with high resistance to fracture for airplanes and automobiles.

A new strengthening process of thermoplastic polypropylene reinforced by interlayered activated sizing film-free carbon fiber treated by electron beam irradiation under oxygen-rich nitrogen gas prior to assembly and hot-press

“…The bare SFF-CF chopped strand mats were homogeneously irradiated on both sides by an electron-curtain processor (Type CB175/15/180L, Energy Science Inc., Woburn, MA, Iwasaki Electric Group Co., Ltd., Tokyo) prior to composite fabrication of PP matrix CFRTP. [1][2][3][4][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] The CF was homogeneously irradiated by the linear electron beam gun with low energy through a titanium thin film window attached to a vacuum chamber of 240 mm diameter. A tungsten filament in a vacuum was used to generate the electron beam at a low energy (acceleration potential, V: kV), of 170 kV and irradiating current density (I, A/m 2 ) of 0.089 A/m 2 .…”

“…where r, P, L, w, t, e, and d are bending stress (MPa), load (N), distance between supporting points (40 mm), sample width, sample thickness, bending strain, and amount of deflection (mm), respectively. 4 Evaluating the accumulative probability of strength (P f ) is a convenient method of quantitatively analyzing experimental values and in industry, is often employed in statistical quality control (QC). P f is expressed by the following equation which is a generalized form of the median-rank method.…”

“…Since its production cycle is short enough to advance cost reduction, its GFRTP (glass fiber reinforced thermoplastic polymer 1,2 ) can be generally applied to automobiles. On the other hand, the strength decreases from using thermoset epoxy to TPs of PP, acrylonitrilebutadiene-styrene (ABS), 3 or polycarbonate (PC) 4 due to easy carbon fiber pullout has been a concern to increase the typically weak adhesion between CF and TP polymers.…”

“…19 EBI has received much attention as a useful tool to directly activate sized CFs prior to assembly and fabrication. 23,24 In metal-polymer joints when used as connecting insert, 0.30 MGy EBI-activated CF increased tensile strength of a Ti-Polycarbonate [Ti/EBI-CF/PC] joint about 3 times higher 4 ; and Ti-Acrylonitrile styrene [Ti/EBI-CF/ABS] joint 2 times higher 3 than that of untreated.…”

A New Process of Thermoplastic Polypropylene Reinforced by Interlayered Activated Carbon Fiber Treated by Electron Beam Irradiation under Nitrogen Gas Atmosphere with Oxygen Prior to Assembly and Hot-Press

“…Up to now, EBI in typical N 2 atmosphere has been used to create stronger adhesion of CF to TPs 1,23) with EBI acting to clean the CF surfaces while activating CFs increasing intermolecular bonding with CF hexagonal structure ³ electrons. However, to increase adhesion further, we employ the novel process of coupling the EBI activation with creating polar groups on the CF surface to proliferate covalent bonds as shown in Fig.…”