Melt polymerized aramid/polycaprolactam copolymer and its fiber

Abstract

A melt polymerization method was introduced to synthesize a series of aramid/polycaprolactam copolymers (APA). In this strategy, a modified aramid (MA) containing para-and meta-disubstituted benzene rings was dissolved in molten caprolactam (CPL) and then copolymerized with CPL to obtain APA. In contrast to neat polycaprolactam (PA6), the glass transition temperature (T g ) and crystallization temperature (T c ) of APA were maximally raised by 9 • C and 135 • C, respectively. The crystal form of APA was similar to that of PA6 and only one α-form existed in the crystallization region of the copolymer. However, the completeness of the crystal grains was disrupted by the aramid component and the apparent viscosities (η a ) of APA were obviously higher than for PA6, which indicated that the aromatic segments in the APA backbone restricted the mobility of the PA6 chains. In addition, APA was easily melt-spun into continuous fiber, and the tensile strength of the fiber was significantly increased by 140.97% with introduction of 5 wt% MA compared with neat PA6 fiber.

Synthesis of heterocyclic aramid nanofibers and high performance nanopaper

“…Copolymerization has been proved to be an effective strategy to adjust the properties of PPTA. [22][23][24][25][26] Herein, we introduce the heterocyclic monomer 2-(4-aminophenyl)-5-aminobenzimidazole (APBZ) as a third monomer to participate in PPTA polymerization and expect to obtain modified copolymerized nanofibers. Heterocyclic aramid fiber is famous for its better strength and tenacity than PPTA fiber.…”