Oriented Crystallization of Polycarbonate by Vapor Grown Carbon Fiber and its Application

Abstract

ABSTRACT:It is known that polycarbonate (PC) is categorized as amorphous polymer and pure PC crystallizes extremely slowly. However, we have recently found that the crystallization of PC was substantially accelerated around 200 C in the presence of vapor grown carbon fiber (VGCF), having ultra thick multi-walled carbon nanotube (MWCNT) structure. To examine the accelerated crystallization by VGCF, the effect of pre-graphitized VGCF, carbon black, and mesophase pitch based carbon fiber (CF) on the crystallization was evaluated. In addition, polarized optical microscope observation was performed by using PC including magnetically oriented VGCF. It was suggested that the surface of ordered graphite structure from VGCF or CF induced the oriented crystallization of PC along the axial direction of VGCF or CF. To utilize the accelerated oriented crystallization of PC by CF, PC sheet having oriented crystallized surface PC layer was made by annealing the stacked structure of PC sheet and oriented CF sheet at 200 C.The PC sheet, whose surface was crystallized along CF axial direction, was successfully produced, showing retardation property by polarized optical microscope.

Crystallization of R-BAPB type polyimide modified by carbon nano-particles

“…These included VGCF and CB type particles. A significant nucleating power of VGCF had been expected in view of the observations in [14,18,19] that even amorphous polycarbonate crystallized at a substantially accelerated rate in the presence of the ordered graphite surface of VGCF and pitch-based graphite fibers, respectively, to form orientated [18] and transcrystalline [19] arrays. Similarly, in this work we have modified the PI by 3 vol% of VGCF.…”

Thermal/Electrical Properties and Texture of Carbon Black PC Polymer Composites near the Electrical Percolation Threshold

“…Such free spaces could be the result of a very limited phase separation process coming from the formation of crystallized PC. The PC crystallization, which is usually a remarkably slow process, may be accelerated at the high process temperature and through the presence of CB, as also observed in the presence of carbon fillers (CB, vapor grown carbon fibers, carbon nanotubes, carbon fibers) [2,42]. Finally, the relatively high pressure of the extrusion in conjunction with the high shear stress of the injection molding process could stimulate, to some extent, the formation of a very small degree of crystallinity that under normal process conditions is nearly completely amorphous [43,44].…”

Magnetic Processing of Diamagnetic Materials

“…If such a nucleating agent is aligned by a magnetic field, it is possible to align the crystal of polymers [65]. Uniaxial alignment obtained under magnetic fields is also effective as a means to investigate the epitaxy between nucleating agents and polymers because other effects, such as shear, which orients the molecular chain, are negligibly small under magnetic alignment [66,67].…”