STRUCTURE OF CARBON-FILMS DERIVED FROM POLYCARBODIIMIDE

The structure of carbon films derived from polycarbodiimide (PCDI) has been investigated in relation to carbonization temperature by using w ide- and small-angle X-ray scatterings. Various parameters characteriz ing the microvoids in an anisotropic arrangement are deduced from the analysis of the small-angle X-ray scattering. The carbon layer planes of the crystallites tend to orient parallel to the film surface with t he growth of the crystallites. It has been found from the comparison o f the microvoid parameters determined on different X-ray optical geome tries that the microvoids in the carbon films do not show preferential orientation even in a carbon him having a relatively high preferentia l orientation of crystallites. The density of the carbon films decreas es at a faster rate with the growth of crystallites. A characteristic nature of carbon films from PCDI is that the development of crystallit es is low in comparison with the development of microvoids. Various st ructural parameters for carbon fibers from different origins are shown for comparison. Copyright (C) 1996 Elsevier Science Ltd Key