Long-range effects of carbon fiber on crystallization of semicrystalline thermoplastics

Non-isothermal crystallization of carbon fiber reinforced polyetheretherketone composites was studied with differential scanning calorimetry and Fourier transform infrared spectroscopy. Composite prepregs prepared by a solution pre-impregnation method with the matrix of different molecular weights were employed in the present work as the main model materials. Analyses of the different dependencies of non-isothermal crystallization on melt residual time in these systems revealed that carbon fibers had long-range effects on bulk crystallization of matrix polymer, which is rooted in the fact that the fibers tend to promote strain-induced nucleation in polymer. Comparison of the crystallization behavior of prepregs with that of the composite laminates indicated the importance of wetting and absorption to the effects of fiber on matrix crystallization, coinciding with the mechanism that short-range interaction formed the boundary to the flow under thermal stress. (C) 1999 Elsevier Science Ltd. All rights reserved.