Jinliang Sun

Conductive aramid fiber with Ni-Cu composite coating prepared using the metalation swelling method

Conductive aramid fiber with nickel-copper composite coating is prepared by consecutive steps of metalation swelling, sensitization, activation, nickel electroless deposition, and copper electroless deposition, respectively. The metalation swelling of aramid fiber makes the follow-up sensitization and activation feasible. The as-prepared samples are characterized by SEM, TEM, XRD and XPS. After metalation swelling, the aramid fibers look like cotton fibers with numerous nano-scale pits of 50–300 nm in diameter. Pd metal as nuclei for Ni crystal growth with the size of 10±5 nm is originated from Pd2+, which can be reduced to Pd0 by Sn2+. The Ni-Cu composite coating of 1-µm thickness has polycrystalline structure. And the electrical resistance of conductive Ni-Cu aramid fiber is 0.035 Ω/cm. The synthesis mechanism of the conductive aramid fiber with Ni-Cu composite coating is given.

Influence of polyethylene glycol 6000 and potassium ferrocyanide on electroless copper plating at the nickel-modified surface of para-aramid fibers

Influence of polyethylene glycol 6000 (PEG6000) and potassium ferrocyanide (K4Fe(CN)6) on electroless copper plating at the nickel-modified surface of para-aramid fibers was investigated in the present work. The surface of para-aramid fibers was roughened using sodium hydride/dimethyl sulfoxide (NaH/DMSO) to guarantee successful electroless plating. Then, electroless copper plating at the nickel-modified surface of para-aramid fibers was adopted because nickel had catalytic activity during the electroless copper-plating process. Meanwhile, PEG6000 can regulate the growth rate of the crystalline grain to produce a morphology-controlled deposit and K4Fe(CN)6 is a brightener and leveling agent for deposit during electroless-plating process. Hence, both PEG6000 and K4Fe(CN)6 were selected as the additives together. On adding PEG6000 to the plating solution, the copper grains turned fine and sleek. Copper deposits became homogeneous, smooth, and compact, and the appearance of deposits changed from dark-brown to red-brown. On adding K4Fe(CN)6 into the plating solution with 4 mg/L PEG6000, the copper deposits became more compact and smoother, and the color of deposits changed from red-brown to bright copper. Correspondingly, the conductivity of deposits increased. In addition, the breaking strength of metal-deposited para-aramid fibers still remained at values up to 45 N.

Fabrication and properties of dope-dyed Poly(m-phenylene isophthalamide) fibers via wet spinning

Poly(m-phenylene isophthalamide) (PMIA) fibers play an irreplaceable role in the area of high-temperature resistance. It is usually difficult to dye PMIA fibers due to their rigid molecular structure and high crystallinity. In this study, the dope-dyed PMIA fibers with different amounts of pigment were fabricated by wet spinning. The properties of the pigment were analyzed, including size distribution and dispersive properties. The results showed that the pigment was easy to disperse in the fibers when the average diameter of the pigment was smaller than 500 nm. The color fastness of the colored PMIA fibers was tested, and their thermal properties and mechanical properties were also analyzed. The results of thermal gravity analysis (TGA) indicated that the colored PMIA fibers maintained good thermal performance. Compared to uncolored PMIA fibers, the colored PMIA fibers became lighter after exposing to simulated sunlight for 50 h. The breaking tenacity of fibers exceeded 2.0 cN/dtex, and the retentivity was above 80 % after being exposed to simulated sunlight for 50 h. These suggested the good mechanical performance of colored PMIA fibers. Dope-dyed PMIA fibers with good mechanical properties and thermal performance were successfully developed.