Nonstop Monomer-to-Aramid Nanofiber Synthesis with Remarkable Reinforcement Ability

• DOI: 10.1021/acs.macromol.8b02391
• Publication Date: 2019-01-17T20:57:53Z
• Authors: Jun Mo Koo; Hojun Kim; Minkyung Lee; Seul-A Park; Hyeonyeol Jeon; Sung-Ho Shin; Seon-Mi Kim; Hyun Gil Cha; Jonggeon Jegal; Byeong-Su Kim; Bong Gill Choi; Sung Yeon Hwang; Dongyeop X. Oh; Jeyoung Park
• Keywords: 02 engineering and technology; 0210 nano-technology

Aramid nanofibers (ANFs), typically produced by exfoliating aramid microfibers (Kevlar) in alkaline media, exhibit excellent mechanical properties and have therefore attracted increased attention as nanoscale building blocks. However, the preparation of aramid microfibers involves laborious and hazardous processes, which limits the industrial-scale use of ANFs. This work describes a facile and direct monomer-to-ANF synthesis via an as-synthesized intermediate low-molecular-weight poly(p-phenylene terephthalamide) (PPTA) without requiring the environmentally destructive acids and high-order shearing processes. Under the employed conditions, PPTA immediately dissociates and self-assembles into ANFs within a time period of 15 h, which is much shorter than the time of 180 h (not including the Kevlar preparation time) required for the Kevlar-to-ANF conversion. Interestingly, the fabricated ANFs exhibit nanoscale dimensions and thermoplastic polyurethane (TPU) reinforcing effects similar to those of Kevlar-deri...