Abstract
This article concerns surface roughness of PBO fibers. Atomic force microscopy is applied to measuring the surface roughness of the PBO AS, HM and HM+ fibers. Also linear thermal expansion was measured. The reason that the surface roughness is decreased as fiber modulus increases is discussed from the viewpoint of microscopic fiber surface structure. There is a discussion in that the smoothness of fiber surface has relation with fiber modulus, molecular orientation and crystallinity of the fibers. The coefficient of thermal expansion is also measured. The PBO HM+ fiber shows a lower value (-8.7 × 10-6 K-1) of coefficient of thermal expansion than that of the PBO HM.