初のナノ核生成直接観察と高分子bulk融液からの均一核生成(<特集>ソフトマテリアルと核形成)

First Direct Observation of Nano-nucleation and Homogeneous Nucleation from the Bulky Melt of Polymer(<Special Topic>Nucleation in Soft-materials)

Okada Kiyoka N.

Hikosaka Masamichi

日本結晶成長学会誌

X線小角散乱法により,技術的問題から80年近く困難であったナノ核生成の直接観察に世界で初めて成功した.ナノ核のサイズ分布f(N,t)を定量的に示し,ナノ核生成の実体を明らかにした.さらに,質量分布関数Q(N,t)を導入して,確率過程における新しい核生成の基礎方程式を提案した.これにより,古典的核生成理論によって提案された核生成の速度論的基礎方程式において,質量保存則を満たさないという重大な問題点を解決した.高分子バルク過冷却融液を,ある臨界の伸長歪み速度以上で結晶化させると,不均一核生成が均一核生成に変わり,形態がマクロな球晶構造からナノメートルサイズのナノ配向結晶体(nano-oriented crystals,NOC)に一変した.NOCは比強度(重量当たりの引っ張り強度)が鋼鉄の数倍で高透明性,高耐熱性を示す"超高性能高分子材料"であることが分かった.

We succeeded in observing nano-nucleation by means of small angle X-ray scattering for the first time, which had been impossible to observe for about 80 years due to technical problems. We obtained size distribution f (N, t) of nano-nucleus and clarified the real-image of nano-nucleation. We also introduced "mass distribution function Q (N, t)" and proposed a new basic equation of the mass conservation law. This solved the serious problem in classical nucleation theory, where so called "fundamental kinetic equation" does not satisfy the mass conservation law. Polymer nucleation is the process of disentanglement and chain sliding diffusion along the chain axis due to the topological nature of chain-like polymers. We showed that nucleation and morphology changed under large elongational strain field: they discontinuously changed from heterogeneous to homogeneous ones and from spherulite to "nano-oriented crystals (NOC)", respectively, when the elongational strain rate increased larger than a critical elongational strain rate. Physical properties of the NOC were significantly improved.

Physics [ 420 ]

jpn

日本結晶成長学会

日本結晶成長学会

本文データは学協会の許諾に基づきCiNiiから複製したものである

[ISSN] 0385-6275

[NCID] AN00188386

[NAID] 110007593833 isVersionOf