Hiroki Murase

Morphological study on poly-p-phenylenebenzobisoxazole (PBO) fiber

Morphological survey on new PBO fiber (Zylon®) was conducted by X-ray and transmission electron microscopic studies. Crystal size, orientation of the crystal, fibrils, microvoids, and fine structure were discussed. It was found that the molecule in the fiber showed high orientation (more than 0.99 in Hermanns orientation function for heat-treated fiber) and relatively small crystal sizes in the longitudinal (160 A) and the transverse (110 A) directions. Crystal modulus estimated by extrapolation to perfect orientation on the plot of the fiber modulus as a function of fiber orientation (Northolts method) shows discrepancy from the crystal modulus directly obtained by X-ray scattering. This discrepancy means that the Northolts model is insufficient to describe the Youngs modulus of PBO fiber. Microvoids elongated to the fiber direction were examined by small-angle X-ray scattering and transmission electron microscopic methods. The diameter of the microvoids was 20 A to 30 A and the fiber had a very thin microvoids-free layer (0.2 μm). Preferential orientation of the a-axis of crystal in the fiber was also confirmed. Summarizing these results, a structure model of the PBO fiber was proposed.

History of Super Fibers: Adventures in Quest of the Strongest Fiber

The high-strength and high-modulus fibers have been widely spread into many industrial applications since the last quarter of the twentieth century. Key technologies leading to the industrial success of the fibers are the molecular designs of rigid polymers giving rise to a spontaneous molecular organization and the gel spinning of flexible polymers. The continuous efforts of a great number of researchers in this field over 40 years are summarized in this chapter.

Controlled Orientation and Morphology of High Modulus and High Strength Fibers.

高分子の配向.配列制御技術の近年のもっとも大きな実りのひとつは.液晶紡糸.ゲル紡糸といった高強度.高弾性率繊維の製造技術である.これらの繊維化技術のキーテクノロジーは流動.伸長場による配向制御であり.本稿では.こうした外場中での高分子の構造形成に関する最近の話題を概説した.